Datron 4000A getting at test points?? - Page 1
Forum section: electronics / repair

author: essele
author_rank: Frequent Contributor
timestamp: March 11, 2019, 09:01:35 am
content: Hi,I've managed to get my hands on a Datron 4000A with a FAIL 7 error, which indicates a problem with the 50V supply. There are a couple of burnt looking resistors on the board, so I'm going to replace them anyway but I'd like to be able to test more thoroughly (btw the +/-15V supplies appear to be ok as I know that's the fault at least one other person had.)My question is really about how to make use of the test points ... this board in particular takes its 15V supplies from the motherboard connector, therefore you can't properly test it if it's not plugged into the motherboard, and then you just can't get at the test points???I managed to test the PSU board using test clips but it was a complete faff and there's just not enough space on the 50V board.I'm probably being completely dense, but how has everyone else seemingly managed to test this?Cheers,Lee.

author: coromonadalix
author_rank: Super Contributor
timestamp: March 11, 2019, 09:21:43 am
content: you could solder some small wires onto the pcb to the tests points ? while being sure they touch nothing when the 4000 is powered ? or connectors extenders ??

author: Johnny10
author_rank: Frequent Contributor
timestamp: March 11, 2019, 11:42:25 am
content: I have worked on my 4000A quite a bit and board extenders would be fantastic !!!But I did as coromonadalix suggested, attach some wires to the test points and carefully reinsert the board.I sometimes had 8 or more wires extending above the PCB boards, works in a pinch.I had the same problem as you with Fail 7.The 15V supply is critical.After replacing all tantalums on power supply board and -15V Voltage regulator(MC7915CT), problem solved.Also make sure that power supply board is seated properly. Had a problem with that also.xdevs has the power supply schematic on his site.

author: essele
author_rank: Frequent Contributor
timestamp: March 11, 2019, 09:57:28 pm
content: Thanks for the comments .. I've made a little more progress, but it now seems like I'm going to need to resort to soldering test wires on.Basically one of the thermistors on the positive heatsink assembly was faulty, and was actually leaking from the metal tab, so I was seeing -15v correctly on J1-2, but +28v on J1-1. I've unsoldered the thermistor and put a 190k resistor in it's place and all seems more normal (now matches the negative heatsink thermistor!)Does anyone know what a TS4-85 is? I know it's an NTC, but I can't seem to find any references anywhere??I'm still seeing a FAULT 7, and just looking at the connector voltages I can see that the +50V rail is perfect, but the -50V is only -42V, so lots to check, but at least I've narrowed it down to the negative rail.Cheers,Lee.

author: Johnny10
author_rank: Frequent Contributor
timestamp: March 11, 2019, 10:27:44 pm
content: I find NTC Thermistor 85 degree Manufactured by Microtherm TS485

author: essele
author_rank: Frequent Contributor
timestamp: March 11, 2019, 10:56:57 pm
content: Thanks Johhny10 but where are you finding that? Even with all of that detail I still can’t find anything???Further progress though ... TP11 was also low, so I started to suspect either the op amp or the reference. Applying a small constant current voltage to the reference showed that the positive one was a good 2.45V, but the negative one was only 2.1V, but out of circuit it was fine! So I’m now fairly convinced that C17 (1uF tantalum) is the culprit... I’ve run out of time now, so hopefully I can get this sorted tomorrow.I’m slightly worried about the previous issue as there was 28V on a motherboard signal which was supposed to be 0V or -15V.Cheers,Lee.

author: Johnny10
author_rank: Frequent Contributor
timestamp: March 11, 2019, 11:49:13 pm
content: I have various resource material collected from my own repairs.I have three Datron 4000 units: 2 working 1 for parts.

author: essele
author_rank: Frequent Contributor
timestamp: March 12, 2019, 09:02:12 am
content: Thanks.Interestingly I've not managed to find any data or references at all to the TS4 range. I have found the TS3 range, but unfortunately they are no longer manufactured (post 2016) due to source materials and production line equipment challenges.The interesting this about these is they have a highly specific transition region at the rated temperature, so I'm really not sure what to do about a replacement.To quote the datasheet...Within this transition region the devices typically exhibit a negative temperature coefficient ranging from 40% per °C to 200% per °C. Below the transition region they exhibit a linear “thermistor” characteristic of -2 to -4%/°C.The only thing I can find at the moment is the 75 degree version, so I've ordered one anyway, hopefully it won't be an issue.EDIT: Actually it may work with a simple normally open thermal switch ... I'll have a look around.Cheers,Lee.

author: coromonadalix
author_rank: Super Contributor
timestamp: March 12, 2019, 11:00:40 am
content: Is there any complete schematics out there ? this is a collection of found items on the web.found this : ko4bb has them toohttp://www.mediafire.com/file/d4lrsde7zv0cyry/Datron4000A.rar27mb

author: essele
author_rank: Frequent Contributor
timestamp: March 12, 2019, 11:19:56 pm
content: I’ve been using the schematics here:https://xdevs.com/doc/Datron/4000A/Datron_4000_Fail_7.pdfSome more progress ... I was completely wrong about the cap, I’ve actually tracked the issue to the negative 50v current limit. I’ve disconnected one leg of D27 so the current limit isn’t active and it all works fine (well almost!) ... so something in that current limit section isn’t right. Everything tests ok, so I think I’m going to have to go back to test wires again. (I am assuming there isn’t actually a large current flow, I should probably check, but nothing seems overly warm.)The voltage and resistance ranges all seem to work ok and are reasonably well calibrated. The 1A current range doesn’t work, but the others are fine. I need to do some work on the front panel keys as they are a bit hit and miss.Good progress for this evening!

author: Johnny10
author_rank: Frequent Contributor
timestamp: March 12, 2019, 11:34:27 pm
content: A couple of points to remember:The calibrator has built in routines that shut the output down making it difficult to discover certain problems.I replaced the same IC on the front keyboard PC on all my units. M4 Dual Binary 1 of 4 Decoder MC14555BCP . It is handy that they are all socketed.On all units, connecting to GPIB allowed me to access remotely all functions of the Calibrator without using keypads.After replacing all tantalum capacitors I had no further errors.

author: essele
author_rank: Frequent Contributor
timestamp: March 13, 2019, 11:18:33 am
content: Thanks -- would be good to know about the keyboard IC. Some of the keys work, but some don't, some definitely need a clean as you can get them to work through different pressures.Do you remember what voltage your 15V rails were? ... mine are +/-14.6V which I was a little concerned about, but they are within 7915 specs. I've ordered all the tantalums for the 15V supply anyway so will replace them when they arrive. I don't think this is the issue though as the 15V rails don't play a part in the over current control, and everything is fine when that bit is disconnected.I'll also change the ones in the overcurrent limit, but they all test ok, so I don't really think it's them. I've also ordered all the transistors and I suspect they are most likely at fault -- if I understand the schematic correctly then some leakage could cause this to happen. I'm also a bit worried that this is a power-on transient issue that causes the over-current circuit to latch on -- more sophisticated tested needed!You don't happen to have a schematic for the current section do you? I get a few mA on the 1A range, it does change with setting, so hopefully something simple. The other current ranges are fine.Cheers,Lee.

author: Johnny10
author_rank: Frequent Contributor
timestamp: March 13, 2019, 12:54:13 pm
content: I chased problems around different boards for hours.It was not until I changed all tants that the errors stopped.I also had a problem with leaving unit sit for a few months in between uses, turn it on and blow a few more tants. AArgh!Voltages on 480455 DC PCB Assy+ 14.90- 14.90What board do you need more info on?This may be helpful

author: Johnny10
author_rank: Frequent Contributor
timestamp: March 13, 2019, 03:58:46 pm
content: 91

author: essele
author_rank: Frequent Contributor
timestamp: March 14, 2019, 08:46:53 am
content: Thanks Johnny10, they are all really useful -- I'll get to that once I've figured out this -50V issue.The final batch of tants should arrive today, so hopefully I can get them all replaced this evening.I didn't have a lot of time yesterday but I did check the voltage drop across the current sense resistor, and there does seem to be a power on spike well into the limit area on the -50V side, the +50V side spikes but is half the magnitude. But I only measured this with my multimeter (fast and graphing) as I didn't have time to satisfy myself about attaching my scope without isolation (and my isolated probe is x200, so not really the most use in this case.)If I'm understanding the schematic there is a 47u tantalum in series with 150R that looks like it should slow the reaction of the current limit by a few ms presumably to stop it triggering on short transients and the turn-on spike. So I think it leaves me with four scenarios...1. This is all tantalum voodoo and they just need replacing (which I will do anyway.)2. The current limit is working fine, and the turn-on spike is indeed much bigger than it should be - so something else is wrong.3. The current limit is triggering too quickly (most likely the cap or associated transistor.)4. The current limit has a fault and is on all the time anyway.If recapping doesn't work, then I'm going to try shorting out the current sense resistor to see if the current limit is being triggered this spike or not ... so that will prove or disprove number 4. Hopefully it proves it as I have all the parts to replace everything in that section now!

author: essele
author_rank: Frequent Contributor
timestamp: March 14, 2019, 09:23:34 pm
content: Aaarrrggghhhh!I'm pleased to say the +/-50V rails are now working and my FAIL 7 error is gone, but I'm not particularly pleased with how long it took and how stupid I am!So I shorted the current sense resistor and yet the problem still persisted, so that was good, it meant the issue was squarely with the current limit circuitry and not anything to do with turn-on spikes etc.So I replaced the two tantalums, no change. Replaced the three transistors (one at a time), no change. I replaced the 1N4148's, no change, I removed and re-tested the two zeners, they seemed fine. I retested all the resistors, they were fine. I swapped the ceramic cap.So I'd changed or tested every single component and it still wasn't bloody working!Because I'd removed two of the heatsink assemblies I had a bit more room, I could start putting test clips on various components, and I eventually found that the 5.2v zener anode, which should have been at -75V (ish) was at -35V ... how can that be? It's directly connected to the darlington and I can probe that on the connector and it's -75V??Anyway, it turns out that it's not directly connected to the darlington, because a small bit of the copper track had come away, so I've just spent hours (and a fair few quid on components) to solve a bloody track defect.Sigh. Lesson learnt.Before and after pictures attached for embarrassment. I've also included a picture of my multimeter with 1v output set, this was only a few minutes after power-up (ignore the historical stats) ;-)Now to move on to the 1A current range problem ... although I'm going to save that for tomorrow and crack open a beer instead.Thanks for your help Johnny10.

author: coromonadalix
author_rank: Super Contributor
timestamp: March 14, 2019, 09:26:39 pm
content: nice finding for the pcb trace, but i would have gone from thru hole to thru hole, i think the pcb trace may fail again ...

author: Johnny10
author_rank: Frequent Contributor
timestamp: March 14, 2019, 09:39:40 pm
content: I did the same thing with a HP3457A, checked and changed a number of parts and still didn't work... then flexed the board and it worked???Split in a trace . AArgh !Good Find.

author: essele
author_rank: Frequent Contributor
timestamp: March 14, 2019, 10:51:21 pm
content: Hi coramonadalix - yes I did think that myself, and then got overcome with the joy of fixing it quickly. I was also considering putting some epoxy on it, but you’re probably right and I should do it properly.Johnny10 - do you have the other half of the schematic and board layout for the I/Ohms board? I couldn’t help but have a quick look, the 0R1 is fine, so I think it’s either the relay or the relay control signals.Also ... is there a way to change from 2 wire to 4 wire resistance? I notice that calibration can be set for each, and I’m assuming it should display accuracy for each, but I can’t find a way to switch?? (1k 4-wire is a bit off, but everything else is great [or my meter is off!!])

author: Johnny10
author_rank: Frequent Contributor
timestamp: March 14, 2019, 11:20:15 pm
content: What happened to going for a beer?Are you getting OL error on Current?I believe pressing OHMS key and SENSE key puts it in 4 wire mode.

author: essele
author_rank: Frequent Contributor
timestamp: March 15, 2019, 08:07:31 am
content: Don't worry ... the beer was consumed!I'm not getting OL, I'm getting a much smaller output than expected, it's actually just over 50 times smaller than it should be (1A gives me 19.926mA, 100mA give me 1.994mA) so I have a strong suspicion that it's using the 5R shunt rather than the 0.1R shunt.I'm slightly confused because that would imply that RL1 isn't switching properly (which I can believe), but also RL3 would need to be closed when it's supposed to be open, and I'm fairly sure it's ok when using the other ranges, so may well be relay driving problems.Is there another schematic covering the relay drivers and logic?I also just managed to get the 2-wire/4-wire switching as you suggested ... it seems to switch every relay in the box in sequence rapidly several times when you change the setting. Is that normal, probably lasts best part of a second, sounds horrible? I'll record it this evening.

author: Johnny10
author_rank: Frequent Contributor
timestamp: March 15, 2019, 12:54:10 pm
content: Switching to Sense makes the repeated clicking sound on my unit also.

author: essele
author_rank: Frequent Contributor
timestamp: March 15, 2019, 06:57:56 pm
content: Hmmm .. I took the board out again and soldered some test wires onto the relay coils so I could see if they were being driven (for RL1) and when I put it back it was working fine!Desoldered the wires, and it stopped working!Soldered them back on, and the left hand relay coil wasn't being driven, traced the tracks and they went to the sub-pcb, so I've just reseated it and it all seems to be working fine (if not slightly low in current reading, 100mA on the 1A range is reading 99.966mA ... which is below the 99.970mA min, but it hasn't warmed up yet, so hopefully this will recover.)So I'm hoping it was a badly seated board, but it could well be another dodgy track or a dry joint ... I will test for a while now.2w and 4w both read spot on so I think everything is functioning now ... just need to look at these dodgy buttons.Thanks for all your help again.

author: Johnny10
author_rank: Frequent Contributor
timestamp: March 15, 2019, 07:21:05 pm
content: As I said before I had problems with boards fully seating.My own error.Great all is up and working!Are you going for calibration?Another member suggested I buy an 8 1/2 digit calibrated DMM instead.Got to save the pennies for that one.Behind the keys pic.Carefully pry off the key top and underneath there is simply a spring.Key snaps on and off to this.

author: essele
author_rank: Frequent Contributor
timestamp: March 15, 2019, 08:31:45 pm
content: I was thinking about seeing if I can find somewhere to get it calibrated without having to remortgage, I do have a 34470A that's about 9 months old and still in factory calibration, it's "only" 7.5 digits, and actually 7 months on, I probably would have bought a Keithley rather than the Keysight, but it is showing me that this 4000A is doing ok, but is maybe very slightly off .. although what do you trust more?But them I'm also running it with the top off at the moment, so I probably have some more test to do before I decide what to do.Thanks for the keys pic ... that's tomorrows job.

author: Johnny10
author_rank: Frequent Contributor
timestamp: March 15, 2019, 08:40:15 pm
content: The description for the 4000 says it can calibrate 8 1/2 digit DMMs but I don't know if anyone on this site would agree.Have you run the Self Test from the front keys?Press Test than hit Safety Reset, that starts the Self Test.Looking for the successful PASS on left display.

author: essele
author_rank: Frequent Contributor
timestamp: March 16, 2019, 07:48:59 am
content: Ok, I’ve managed to sort out the first four keys, getting the caps off followed by contact cleaner and then contact lube seems to do the trick. Will work through the rest today.I’ve noticed one of the keys has a broken attachment (the tiny plastic bar at the side that the cap clicks on to), it was stuck in the key cap rather than on the main switch. I’ll have a go at glueing it but don’t hold out a lot of hope.Does anyone know of a source for these buttons? They seem to be NSF controls K type half buttons, I’m fairly sure the part number is 623300-010-000-010, and Farnell in Singapore seemed to sell them at some point, but now Farnell (at least UK) only seems to have other variants.On the self test, I’m pretty sure I managed to do that yesterday by mistake and it passed, but will try it again today ... it didn’t take very long, just two or three seconds??EDIT: All keys now working fine ... strangely the broken one clicked back in and seems to be fine ... would still be nice to have a source for spares though.

author: essele
author_rank: Frequent Contributor
timestamp: March 16, 2019, 11:18:40 am
content: Just looking at the accuracy, now with the top cover back on...On the 1V range, set at 100mV, it's supposed to be between 99.9983mV and 100.0017mV.On the 100mV range on my 34470 I was getting roughly 99.9989mV once it warmed up, within just about 1uV ... so that's pretty good. But actually when you look at the spec of the 34470 in 100mV it's 40+35ppm, even for 24 hours it's 30+30 ... so that's 6uV ... so this 4000A is right on the money, at least given the limitations of how I'm measuring it!Switching to the 34470 1V range, the spec is better at 20+4 for a year, so that's 6uV for the 100mV input ... on that range I'm reading a rock solid 0.0999994V, so 0.6uV .. happy with that!At 1V output on the 1V range, it's supposed to be between 0.9999915V and 1.0000085V (8.5ppm) ... I'm reading 0.9999889V which is low, but again the meter is only good to 24ppm at these settings, so this is all within spec.10V is 5ppm on the 4000A, 18ppm on the meter, and I'm reading 9.999917V, so about 8.5ppm out ... all good.100V is 9.5ppm on the 4000A, 44ppm on the meter, I'm reading 100.00063V, so about 6.5ppm out ... good.1000V is scary, and 10ppm on 4000A, 44ppm on the meter, I'm getting 1000.0073, so 7.5ppm out ... good.The lower ranges seem to be digit accurate!100mA is giving me 100.00215mA, within 4000A's 50ppm.10mA is giving me 10.000368mA, within 4000A's 50ppm (close ... but then the meter is 700ppm on this range!)1mA is giving me 0.9999868mA, again within the 50ppm.100uA is giving me 100.00205uA, again within the 50ppm.Now the historical problem child...1A is giving me 0.999918, but seems to take a while to settle ... dropped from 0.999945 over about 5 mins, although this is again within spec (125ppm) and the meter is 900ppm!2w - 1R is good ... should be 1.380 (1.311 - 1.449) ... I'm getting 1.3812 ... how good is that!2w - 10R is also good ... should be 10.369 (10.317 - 10.421) ... I'm getting 10.3739 ... excellent!In fact all the 2w resistance ranges are excellent, with the 1M and 10M being slightly high, but still within the 4000A tolerance.4w - 1R, 10R and 100R all really quite high. The seem to have a 0.014 ohm offset ... something strange going on with my meter here I think, when I set the 4000A to zero I get that offset on the meter, when I null it goes to zero, then re-applying the resistance it's low ... I'm going to blame the meter on this one, and I'm not sure what null of 4w really does.4w - 1k is within 4ppm.4w - 10k is slightly high about 10ppm above the max, but the meter is 45ppm.4w - 100k is similarly high.4w - 1M is good.within 20ppm on a 40ppm tolerance.4w - 10M is good, but jumps around a bit, probably not the best test setupSo all in all, I think that's all bloody great ... not sure I'll rush to get it calibrated, although I have asked for a couple of quotes. As suggested, might be better of with an 8.5 digit meter instead ;-)

author: Johnny10
author_rank: Frequent Contributor
timestamp: March 16, 2019, 12:24:48 pm
content: Never found a Datron 4000A user manualI believe you can look over the Datron 4708 user manual for diagrams to setup device test wiring.AlsoThe 4708 Current/Ohms board is very similar to 4000.

author: coromonadalix
author_rank: Super Contributor
timestamp: March 16, 2019, 06:10:59 pm
content: Great Happy for you and your Datron 4000A, would be nice if some one could post and host a complete manual ...A slight word of warning, be carefull with contact cleaners, if they are petroleum based or sillicon based, some plastics doesn't like thatNow go Fin a 3458 loll hush hush loll a future volt nut lollI dont see them lately under 2,5K $$$ hish

author: branadic
author_rank: Super Contributor
timestamp: March 18, 2019, 09:52:22 pm
content: Please stay tuned, my Datron 4000A including the user manual with schematics is on its way. Once received I will scan them and post them here.-branadic-

author: essele
author_rank: Frequent Contributor
timestamp: March 18, 2019, 10:22:57 pm
content: Hi branadic,Excellent - I think there will quite a lot of interest in the manual and schematics.Enjoy the 4000A ... it’s a stunning bit of kit!

author: branadic
author_rank: Super Contributor
timestamp: March 20, 2019, 12:56:41 pm
content: My Datron 4000A received today and it looks like it got damaged during transport, so this could turn out to be a repair thing as well. Looks like the left VFD is cracked, for what I can currently see.I'm out for a business trip for the rest of the week, so I have no time to tear the calibrator apart nor the time to fire it up.However, the user's handbook, part lists and drawings addendum as well as the calibration and servicing handbook were included. So the scans are coming soon.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: March 22, 2019, 07:31:07 pm
content: QuoteI was able to diassemble the front of my Datron 4000A today and found two broken gas discharge displaysDatron Part. No.: 800017, Describtion: 8 1/2 digit display with legend, Manufacturer: DaleIf someone has an old front pcb, replacement displays or a hint to someone who can help, please contact me. Thank you very much.-branadic-

author: coromonadalix
author_rank: Super Contributor
timestamp: March 22, 2019, 08:27:30 pm
content: oh damn thats hard to see beaten this way ..did you have it insuredthey are used in the 1062 too8.5 Digit DisplayDatron P/N: 800017Dale P/N: PD-09D064-1Catalog P/N: PD009D06401G02End of life displays in 2012https://www.mouser.com/PCN/Vishay_PCN_DR_001_2012_Rev_0.pdf

author: Johnny10
author_rank: Frequent Contributor
timestamp: March 22, 2019, 10:46:09 pm
content: Have seen a couple of units with that same broken displays.I wonder if it could also happen from picking it up from front and it pushing against your body?They are really heavy.

author: branadic
author_rank: Super Contributor
timestamp: March 23, 2019, 09:22:35 am
content: Looks like there are only three options:1. use it without the front pcb over GPIB interface and make the front a blank black panel2. buy serveral "for parts only" units to get spare parts which is pretty hard from a german point of view as most units are in the US and shipping and customs are rather high3. develope a complete new front pcb based on5.5" OLED DisplayorRET025664DGPP3N0 Display OledI like the idea that there is a member out there having some of them and is willing to sell two of them.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: March 23, 2019, 11:12:13 am
content: I also need at least 3 black switches, that are broken. So if someone is willing to sell them, please contact me.-branadic-

author: essele
author_rank: Frequent Contributor
timestamp: March 23, 2019, 11:15:08 am
content: Hi branadic,I’ve dropped a note to the manufacturer to see if there is any way we can get some supplies of the buttons, I think it would be useful to have a few spares.I’ll let you know when/if they reply.

author: coromonadalix
author_rank: Super Contributor
timestamp: March 23, 2019, 11:33:59 am
content: Quote from: branadic on March 23, 2019, 09:22:35 amthe 4th idea would be to have a new vfd, cloned from the originals ......

author: branadic
author_rank: Super Contributor
timestamp: March 23, 2019, 12:02:10 pm
content: QuoteWould you please elaborate on how to manage that?-branadic-

author: coromonadalix
author_rank: Super Contributor
timestamp: March 23, 2019, 03:46:54 pm
content: Dave did give some hints about designing your own lcd, You have some threads here and thereThis display was sold by Vishay up to year 2012, you'll have to do some digging on the vfd insides, and use the datron schematics you can find, do the pins mapping etc ... but in the end you have to find a place who will build a prototype and check it once it is buildAnd try to have some volume Quoting, say for 100 pieces ??If not, do an mod hack lcd to leds / oleds displays, like many meters we saw hereQ: how far will you go to save your Datron, 2 vfd's to change, that's a lot ??Will you put it aside and try to find another one for parts ?? and it may be a case of bad design consideratons, IE: if the front panel receive some pressure, the vfd's may break again ?? lots of $$$Or try to make it work as mentioned, thru the gpib port ??On another thread, i managed to scoop 2x vfd's for my 34401a at 30$ a piece at Aliexpress, one Ebay seller has it now at 35$ usd, it works very well in my case, a brand new vfd and display + pcb is 200$ usd at Keysight, and they will be obsolete in maybe a year or two ...

author: branadic
author_rank: Super Contributor
timestamp: March 23, 2019, 04:18:40 pm
content: Well, getting made a LCD is a different story compared to getting made a VFD or gas discharge display.Also modifying a unit to fit an available VFD likeD0116SY-20-1601FBisn't easy and even more complex if you can't measure on a working unit to translate it to the proper characters.I would be in if there was some effort for a group buy for getting made some custom gas discharge displays as a replacement, but have no experience in getting them made or designed.-branadic-

author: coromonadalix
author_rank: Super Contributor
timestamp: March 23, 2019, 05:39:57 pm
content: I dont understand why so many companies are still going for vfd's ....... that's another debateI would be curious to know how much is the fluke 8845, 8846 vfd'sIf the Chineesium ones work for my 34401, since the specs of the originals have been copiedMaybe a kickstarter campain would workthere's Datrons out there who need this display ??I do hope you find antoher 4000 with good vfd's

author: branadic
author_rank: Super Contributor
timestamp: March 24, 2019, 11:53:18 am
content: QuoteWell, that would only make sense if it is completely broken except the front pcb.I contacted Noritake Europa for custom displays, but they can't help either as all tools have been destroyed and they have no chance to reproduce themStill I have a few other irons in the fire, so hope dies last (... but it dies.)-branadic-

author: coromonadalix
author_rank: Super Contributor
timestamp: March 24, 2019, 01:25:59 pm
content: thks for the schematicsMy maybe stupid guessThe vfd's are common anodes if i see correctly, why not convert this circuitry into led ones ?? at my job we have very small low profile smt ledI'm sure it could be fitted on a custom pcd who would be less thicker than the vfd's ?? and add a classic red led diffuser on it ??The -175 vdc line could me changed to a more powerful 5 volts, the small markings on A1 A10 and A11 needs to be adressed, somekind of a mask ?---------------------Maybe Qu1ck member here could help / give some hints to convert this into a oled display ?? decode the matrix and push it into a controller like he did for a 34401a vfd to oled projectOr do a crazy adventure like redesignng a new front pcb panel ??Even something like an 2x40 or 4x40 lcd ?? you have some arduino code to do big caracters/ fonts on the two display lines, i played with this code to test 2x40 lcd in the pastor even a glcd 256x64 display ... the list goes onskies are the limit loll

author: branadic
author_rank: Super Contributor
timestamp: March 24, 2019, 03:47:33 pm
content: QuoteWell, that seems to be the only way without touching the unit to much, an LED display that replaces the gas discharge tube. I already started to reverse engineer the display tracks (picture of the front with an overlay of a picture of the back slighly transparent). It will be a bigger task to draw something similar in Eagle.-branadic-

author: coromonadalix
author_rank: Super Contributor
timestamp: March 24, 2019, 06:58:04 pm
content: You could do a sngle board to cover the 2 vfd's who will go over the buzzer and keep everything straight in one shot ??

author: branadic
author_rank: Super Contributor
timestamp: March 24, 2019, 07:25:58 pm
content: The display is 32mm x 173mm in size and if this should ever work there would be plenty of units (meters and calibrators) that could benefit from a direct display replacement.So I like the approach of replacing only the gas discharge display with some custom LED board with character cover inverse printed on a diffuse foil.-branadic-

author: coromonadalix
author_rank: Super Contributor
timestamp: March 24, 2019, 09:43:45 pm
content: Niiice it could fit the 4000 series and a 1062 if i recall, maybe others with the same vfd

author: branadic
author_rank: Super Contributor
timestamp: March 25, 2019, 11:20:41 am
content: Since we have all the information (see pdf above) about the display it should be straight forward to design a LED based display. All it takes are a few 1206/200V series resistors, the LEDs and a pcb layout. In the end the display will draw less current compared to the 64mA per segment of the original gas discharge display. No modification on the front panel required.Relating to the pdf above (page 3) we have a +5V rail, with a 1k series resistor going to the anode, a series resistor of value 1k8, 2k7, 4k7 for the brightness of the segments going to -175V. This is 180V/2k8 = 64,3mA worst case.The voltage across the individual segment is rather low.So all it takes is a series resistor capable of handling the high voltage (1206, 200V should be capable to do the job, close to the anode pin) and a LED, e.g. a red LED with a voltage of 2.1V. Using a maximum of 15mA for the brightest segment this gives 12k overall series resistor . So it will take a bit of try and error to find the perfect value to make all segments look equal in brightness.-branadic-

author: Johnny10
author_rank: Frequent Contributor
timestamp: March 25, 2019, 01:23:31 pm
content: I remember a youtube video about these displays from a while back not sure if it would apply to Datron 4000 ?

author: branadic
author_rank: Super Contributor
timestamp: March 25, 2019, 02:23:11 pm
content: I know this video and solution, but:1. feedbackloop himself was not happy with the result2. it's not a direct display replacement, so individual decoding for every type of instrument is necessary-branadic-

author: 3roomlab
author_rank: Frequent Contributor
timestamp: March 25, 2019, 06:02:23 pm
content: Quote from: branadic on March 25, 2019, 11:20:41 amhmmm not sure what is the drive currentreference from MAX6921-MAX6931.pdf, if the existing circuit drives around max 1.5mAthere is a limited number of leds that could do it.from digikey list, SML-P11x gives around 2mcd at 1mA16-219AUTD/S3151/TR8 gives around 40mcd 1.25mAnot sure how much mcd is a good readout? a 100?an alternate idea to the repair video using a mixture of matrix for symbols + 7 segment on indirect drivefeasible?

author: branadic
author_rank: Super Contributor
timestamp: March 25, 2019, 07:09:59 pm
content: I see no problem here, in worst case there is a current of ~64mA peak flowing through the gas discharge display, thus ~15mA by a LED is much smaller.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: March 25, 2019, 09:05:14 pm
content: Quote from: essele on March 23, 2019, 11:15:08 amI got answer today from NSF Controls Ltd, the "NSF K12 / HALF KEY. BLACK" has the part number 623300010000010. There is a minimum order quantity of 50 off for this part. The cost per switch is £5.83 each and there is a lead time of approx 6 weeks. So maybe we can organize a group buy? Anyone interested in?-branadic-

author: maginnovision
author_rank: Super Contributor
timestamp: March 25, 2019, 10:26:39 pm
content: I could go for 10.

author: essele
author_rank: Frequent Contributor
timestamp: March 26, 2019, 01:35:48 am
content: Yes, I got exactly the same response from NSF, I'm also happy to go for 10.I expect that price will be +VAT so you'll probably need to add 20% ... not sure how they'll handle exports. I'm happy to sort from the UK if it makes sense.

author: branadic
author_rank: Super Contributor
timestamp: March 26, 2019, 06:52:55 am
content: I'm also in with 10 and I would take a few more to make that order happen, otherwise the broken switches are unusable.Since NSF is located in UK it would make sense if you could order and ship them? Otherwise I will do that and since they have a lead time of 6 weeks I don't want to wait to long with ordering them.-branadic-

author: maginnovision
author_rank: Super Contributor
timestamp: March 26, 2019, 07:13:44 am
content: Unfortunately my unit decided to throw fail 6(and 5, and 2) codes. Opened the thing up and the battery was on the bottom of the unit, not attached to the PCB with the negative lead disconnected. I re-attached it but obviously no change. I don't plan on getting rid of it but I have time to wait on switches. I would be willing to take more than 10 as well if needed to get some. Guess I have no reasons not to replace all the caps before I get it calibrated.

author: BNElecEng
author_rank: Regular Contributor
timestamp: March 26, 2019, 07:35:54 am
content: Put me down for 10 switches as well.

author: essele
author_rank: Frequent Contributor
timestamp: March 26, 2019, 08:30:16 am
content: Ok, sounds like we have enough to place a switch order ... I’ll just confirm the VAT situation and then we can get an order placed.

author: branadic
author_rank: Super Contributor
timestamp: March 26, 2019, 08:47:51 am
content: Quote from: essele on March 26, 2019, 08:30:16 amWonderful.Quote from: maginnovision on March 26, 2019, 07:13:44 amNeed to dig into the manual and find the describtion for the errors...-branadic-

author: essele
author_rank: Frequent Contributor
timestamp: March 26, 2019, 10:58:47 am
content: OK, so I've confirmed pricing and delivery with NSF and I'm happy to order 50 of these switches and get them delivered to me in the UK, I can then ship out batches of 10 to those that are interested.So the price is £5.83 per switch, plus delivery is £15 per box, and all of that has VAT added (20%)So the total cost for me to get them delivered is £367.80, that makes them £7.36 per switch (plus delivery to your location.)They are definitely not low cost switches!I'm happy to place the order now, and we can sort out money when they actually arrive, but please don't all disappear as I'm not sure I'll survive a discussion with my wife about how I spent nearly £400 on a box of 1980's switches!Interested parties:-- maginnovision x10-- branadic x10-- BNElecEng x10-- myself x10So there's another 10 up for grabs, but I'm still ok to place the order now, we can work out how we deal with these later, we may just need to take another couple each if nobody else wants them.Please shout quickly if you are no longer interested, otherwise I'll try to get the order placed later today/tomorrow.

author: branadic
author_rank: Super Contributor
timestamp: March 26, 2019, 11:08:14 am
content: Quote from: essele on March 26, 2019, 10:58:47 amPerfectAs I said before, if necessary I would take 20 of them to make this order possible. Paypal works fine for me and if that helps I can prepay today, so you don't get any problems with your wife-branadic-

author: maginnovision
author_rank: Super Contributor
timestamp: March 26, 2019, 03:12:21 pm
content: I'm good with that and PayPal works for me. Just let me know when and where to send payment.Quote from: branadic on March 26, 2019, 08:47:51 amI know 6 is Cal. 2 and 5 show up with certain actions so I'm pretty sure they're related. The thing worked perfectly when I first plugged it in but once I put it where it goes, all errors and battery wasn't where it should be. If the seller refuses to give me a discount or anything it'll suck but since it lost Cal I already changed the key, and cleaned up the filter mess. Cleaned the front up and some dust. New filter on the way, I'll order caps as soon as I count them all out. I'm not so sure about the really big ones though.

author: Johnny10
author_rank: Frequent Contributor
timestamp: March 26, 2019, 04:54:26 pm
content: That would be a bummer if you lost Cal Data when the battery fell out.

author: maginnovision
author_rank: Super Contributor
timestamp: March 26, 2019, 05:19:35 pm
content: Quote from: Johnny10 on March 26, 2019, 04:54:26 pmI definitely did, and it is a bummer. The battery hit the bottom of the case and the resistor on the negative lead went with it opening the circuit. The seller did agree to a partial refund though(50%). The good news is I can do all repairs and preventative maintenance without worrying about messing it up now. I have one more avenue I can take to hopefully cut the Cal cost significantly but one thing at a time.I went ahead and reset calibrations properly so I can get an output. Now I can use it as long as I use the Prema to dial it in until I Cal it. This is 100.00000V according to the Prema. Edit: added 10V image. Master ref may need trimming.

author: branadic
author_rank: Super Contributor
timestamp: March 26, 2019, 07:02:20 pm
content: Good to know it's alive.I'm making progress on the LED display, but it will take a while to finish the design.-branadic-

author: maginnovision
author_rank: Super Contributor
timestamp: March 26, 2019, 07:20:41 pm
content: Quote from: branadic on March 26, 2019, 07:02:20 pmYeah, I wasn't too worried and now getting it for so much less I don't feel bad. Once I get some Cal quotes I'll see about trying to get that for little to nothing.That display mockup looks pretty good. It'll have to be bright to use with the front panel filters though. I do wish I could get old units cheaper but for Datron 1062 around here even not working they go for 100+ bucks. Big gamble for displays. Sellers across country want an extra 100 too for shipping.

author: branadic
author_rank: Super Contributor
timestamp: March 26, 2019, 10:08:19 pm
content: QuoteThere is the option to use two LEDs for the number segment, but I will start with only one LED for each segment first.Design almost done. If this works this replacement could save a lot of meters and calibrators from an end in the dumpster.-branadic-

author: maginnovision
author_rank: Super Contributor
timestamp: March 26, 2019, 10:32:17 pm
content: Quote from: branadic on March 26, 2019, 10:08:19 pmJust need a blackout filter with symbols printed. That and two LEDs per num segment and it'd be perfect.

author: pelule
author_rank: Frequent Contributor
timestamp: March 26, 2019, 11:45:33 pm
content: I am searchin a solution for my 2nd Datron 1281 value display (V1).Out of my tests with white OLEDs (good viewing angle) and other graphical display I got the same conclusion as above - bad brightness.A typical VFD has ~350 cd. A graphical display ~80 to 150.So I have thought about a LED solution also.Best would be high brightness green LED's with a luminanz of ~500mcd @ 20mA.As higher luminanz as better to have the chance of multiplxing.As the LEDs will be such bright just blackout filter on the top will be not sufficiant. The LED's will shine to the near segments also, this will distrub the reading especially in darkness. So my thought was to use a 3d printer to print a masking case. In addition this should help to need/use only one LED per segment./PeLuLe

author: maginnovision
author_rank: Super Contributor
timestamp: March 27, 2019, 12:17:31 am
content: Quote from: pelule on March 26, 2019, 11:45:33 pmYea, to keep current draw low I was thinking lower brightness but more direct hence the blackout. A sort of masking box could work but might be very complicated with so many segments so close. Although even a lower brightness display would be preferable to a dead display. There are so many examples of displays which are dim and little more than a "few leds" trying to display readable data. Once he's able to try a display he'll have a better idea of what more should be done. I've got a wurth led design kit here I was going to see what might work best. There is probably going to be some compromise between readability, brightness, and uniformity in comparison to the original displays.

author: pelule
author_rank: Frequent Contributor
timestamp: March 27, 2019, 05:53:07 am
content: That's engineering. Working with the available to get the best compromize./PeLuLe

author: essele
author_rank: Frequent Contributor
timestamp: March 27, 2019, 06:04:27 am
content: Ok, switch order is placed and paid for.If you drop me a PM with your email address we can stay in touch via email.BTW -- loving the LED work, very keen to see how this turns out.

author: branadic
author_rank: Super Contributor
timestamp: March 27, 2019, 06:56:40 am
content: QuoteThat was exactly what I was thinking of and using one of those sausage printers (FDM) with black filament should work. However, I will need a mask with the symbol print on top of that.I guess I will draw an additional second board with 2 LEDs per segment. There are currently 95 LEDs per board plus one series resistor per LED, so quite a lot. If you can pervent to double their amount that would be great.-branadic-

author: coromonadalix
author_rank: Super Contributor
timestamp: March 27, 2019, 08:20:30 am
content: I think the best led colors would be green, blue (cyan) and amberTo respect the "old" vintage look i would personally go with amber, i think they would be more visible than red

author: branadic
author_rank: Super Contributor
timestamp: March 27, 2019, 02:54:22 pm
content: I think green is a very bad idea, since the front panel foil is greenish/brownish, thus the light will be filtered out. I would go for red or orange.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: March 27, 2019, 06:12:55 pm
content: Is someone able to help converting a png file into dxf? (Size 165mm x 24mm)-branadic-

author: maginnovision
author_rank: Super Contributor
timestamp: March 27, 2019, 06:57:47 pm
content: Quote from: branadic on March 27, 2019, 06:12:55 pmI should be able to but it'll be some time before I'm at my PC. AutoCAD on my phone doesn't work well enough.Let me know if this works. I used a png to dxf tool, then modified the DXF's. It's actually a rar archive I just renamed it to get it to upload. In b-w the characters are all solid hatched, w-b the background is solid hatched.

author: branadic
author_rank: Super Contributor
timestamp: March 28, 2019, 07:40:58 pm
content: Thanks, but I can't get it extruded to a 3d object (e.g. to make it a 3d step file).-branadic-

author: maginnovision
author_rank: Super Contributor
timestamp: March 29, 2019, 01:14:39 am
content: Quote from: branadic on March 28, 2019, 07:40:58 pmGot it, let me see. I wasn't thinking about why, just what.

author: maginnovision
author_rank: Super Contributor
timestamp: March 29, 2019, 02:40:02 am
content: Ok, try these. One is a single surface, one is a full mesh.https://1drv.ms/u/s!AkskRQtlvkhViLAyUVQN8CyD4ZWw3Q

author: branadic
author_rank: Super Contributor
timestamp: March 29, 2019, 12:02:22 pm
content: Thanks, but the dxf files appear to be empty? Can't import a single line and also online dxf viewer don't show anything-branadic-

author: maginnovision
author_rank: Super Contributor
timestamp: March 29, 2019, 03:37:26 pm
content: Ok I'll check it asap. Which tool are you using to import so I can test it? This is what I'm seeing in autocad, and sharecad.org shows me the same thing so I think it's easiest to know what tool especially with the time difference.https://autode.sk/2FE6iAk

author: branadic
author_rank: Super Contributor
timestamp: March 29, 2019, 07:07:14 pm
content: I use Freecad and want to make a 24mm x 165mm x 1mm thick plate. A STEP-File would also help a lot. I could then add the rest by boolean operation to make a complete cover out of it.-branadic-

author: maginnovision
author_rank: Super Contributor
timestamp: March 29, 2019, 08:02:40 pm
content: Ok, there is no direct transfer of the DWG(I use dwg and save it to dxf) to step but in a couple hours I can do that. The DWG right now is the correct dimensions. Then I'll also try to get freecad and try to make that work right. Maybe it's not happy with the format for some reason.

author: branadic
author_rank: Super Contributor
timestamp: March 29, 2019, 09:55:04 pm
content: I've finished the version with 2 LEDs per segment. After a final check I will order the boards on sunday at Elecrow with black solder stop mask. I need at least two boards, but if someone wants to jump on the train please send me a private message with your mail address and the required quantity of boards you need. I accept paypal.-branadic-

author: maginnovision
author_rank: Super Contributor
timestamp: March 29, 2019, 10:43:15 pm
content: Ok here is the step, do you want a freecad file too?

author: guenthert
author_rank: Frequent Contributor
timestamp: March 29, 2019, 11:24:47 pm
content: I don't mean to derail this thread or curb your enthusiasm, but have you verified (access via GPIB, I suppose) that the calibrator is otherwise in good (or okay-ish) condition? I mean, if it drifts badly and can't be economically repaired, then the display is the least of your worries and replacing it would be moot, wouldn't it?

author: maginnovision
author_rank: Super Contributor
timestamp: March 29, 2019, 11:39:18 pm
content: Quote from: guenthert on March 29, 2019, 11:24:47 pmI believe it was sold as working. However an included weston cell damaged the displays. It's really not a huge cost anyway for him to do this and others can benefit since there are many datron products using these displays.

author: branadic
author_rank: Super Contributor
timestamp: March 30, 2019, 09:37:23 am
content: Yes, the calibrator was sold as working and was working, but unfortunately the seller added something to the package by good will. The package top was marked with arrows + text, but shipping companies tend to ignore such markings and the package must have been flipped during transport. Thus, the add on was putting force to the front and that damaged the displays by inattention of the shipping company.So I have no doubt the unit is fully working after the display has been replaced.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: March 30, 2019, 09:52:25 pm
content: Quote from: maginnovision on March 29, 2019, 10:43:15 pmThanks, that STEP file is working for me.-branadic-

author: maginnovision
author_rank: Super Contributor
timestamp: March 30, 2019, 10:31:06 pm
content: Quote from: branadic on March 30, 2019, 09:52:25 pmOk great, luckily Fusion 360 can natively manage DWG and STEP.

author: branadic
author_rank: Super Contributor
timestamp: March 31, 2019, 10:15:29 am
content: PCB order has been placed, now it takes a few days for them to arrive. Interesting to note that only one member wanted boards. So obviuously I overestimated the need for a replacement. However, I ordered a quantity of 10 boards, so if you change your opinion feel free to contact me.-branadic-

author: coromonadalix
author_rank: Super Contributor
timestamp: March 31, 2019, 12:17:21 pm
content: Maybe its to want to see it work before you buy ?? it would be my case ... i want to believe it will work and help many members, the display are getting harder to find, and the used / or defectives units will rise over time.Do you have a bom list ?? or an average price of the display once the leds are put on it ?thks

author: branadic
author_rank: Super Contributor
timestamp: March 31, 2019, 12:33:24 pm
content: It's simply 192x LEDs 0603 (red or orange, while orange should work best as I found the front panel filter passes orange when shining with a white LED lamp trough it) and 95x resistors 1206 per display. The resistor values need to be determined for best brightness. So where is the risk that this solution won't work?The price for resistors plus LEDs can be calculated by everyone himself depending on his source for components.-branadic-

author: MaxFrister
author_rank: Regular Contributor
timestamp: March 31, 2019, 04:30:20 pm
content: It is interesting to note that the display has two square dots that are not in the diagram in the 1081 manual. Do any of these instruments use them?

author: branadic
author_rank: Super Contributor
timestamp: March 31, 2019, 04:48:53 pm
content: They are in the schematics of Datron 4000A named as LKA + ALKA and RKA + ARKA.-branadic-

author: pelule
author_rank: Frequent Contributor
timestamp: March 31, 2019, 05:43:20 pm
content: What power consumption do you exspect?192x LEDs (two per segment) = 96 LEDs current, assuming an avrage of ~10 mA == up to ~1A peekDo I misdunderstand the circuit?/PeLuLe

author: coromonadalix
author_rank: Super Contributor
timestamp: March 31, 2019, 05:58:24 pm
content: The test would be with all 1888888 segments, but it is multiplexed, i dont know at witch frequencyI dont think it will go up at / to 250-500 ma ??

author: feedback.loop
author_rank: Frequent Contributor
timestamp: March 31, 2019, 10:48:02 pm
content: I am quite curious how this will turn out. For my replacement project I tried graphics displays because in my view making intricate mechanical parts is the hardest part. This LED-based design needs some sort of a front panel with symbols, which needs some precision mechanical work. I am not sure I understand how exactly are you going to produce that. Is it a 3D-printed part? Soldering so many LEDs and resistors is also tedious, but manageable.

author: branadic
author_rank: Super Contributor
timestamp: April 01, 2019, 09:16:25 am
content: Yes, it's a 3D-printed part using FDM for a first try. Already placed the order for that.Soldering the LEDs and resistors is just a diligent but routine piece of work, nothing fancy. Some minor modifications on the front panel seem to be necessary, by now it looks like some resistors needs to be changed in value to fully turn on/off the LEDs.The LEDs are multiplexed, so the average current is small.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: April 05, 2019, 03:20:12 pm
content: Scanned (400dpi) and uploaded "Users Handbook" and "Part Lists and Drawings Addendum" for Datron 4000/4000A tohttp://www.ko4bb.comBoth should be available for download briefly. Still need to scan "Calibration and Servicing Handbook", coming soon.KO4BB Recent UploadsEdit: Also uploaded all my documents for Prema 5017 SC and Burster devices...-branadic-

author: maginnovision
author_rank: Super Contributor
timestamp: April 05, 2019, 06:49:07 pm
content: Quote from: branadic on April 05, 2019, 03:20:12 pmI thanked your post but that's great and I'm really thankful you've taken your time to do this. In addition to the replacement display that I'm looking forward to seeing.

author: branadic
author_rank: Super Contributor
timestamp: April 06, 2019, 04:00:26 pm
content: Added also Calibration and Servicing Handbook to ko4bb. It looks like it takes longer as expected. In case you need the documents immediately please contact me and I send you a we transfer link for download.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: April 09, 2019, 07:44:22 am
content: The files are now available for download:http://www.ko4bb.com/getsimple/index.php?id=manuals&dir=06_Misc_Test_Equipment/Datron/Datron_D4000A-branadic-

author: branadic
author_rank: Super Contributor
timestamp: April 10, 2019, 09:32:28 am
content: Update:Display boards are on their way. I have worked out different modifications necessary to make the board working as a replacement, parts such as transistors and resistors that needs to be replaced on the front panel board have been ordered. The display covers have been printed and I will get them soon as well.I expect to make a first assembly within the next 1 - 2 weeks.-branadic-

author: maginnovision
author_rank: Super Contributor
timestamp: April 12, 2019, 07:14:20 am
content: Well I was able to calibrate my unit today. All DCV is good, current is good except 100uA is 100.0200uA and 10mA is 10.01000mA. Ohms is good EXCEPT 1 Ohm because it's about .0012 ohms out of range. After running for 12 hours though it doesn't seem to have any issue and it's pretty stable. In the 100uV range it was pretty tough to dial in the 10's of nV though, mostly due to noise so I had to use 20s integration time. A second 7.5 or 8.5 digit meter would have been nice to double check with but since I don't have another that's calibrated at least I won't be able to tell it's off.

author: essele
author_rank: Frequent Contributor
timestamp: April 12, 2019, 07:32:01 am
content: Hi maginnovision,That's great news ... I would be a little suspicious of those current numbers though, they seem a little too round.I had an issue that RL1 wasn't properly switching (into one of it's latching states) and I think it then left the 5-ohm path still in place, so I ended up with nearly 10mA in the 1mA range, and about 20mA in the 1A range. I could see the lack of signal on one of the relay coils.Whilst soldering various test wires this went away and everything was fine, but a few days ago it came back ... I spent some time yesterday debugging again and found that I was seeing only very short < 500uS pulses on that particular line (the 1A range out of M6) ... I soldered some test wires to the three input lines of M6 and everything is great again ... my guess at this point was that one of those three lines was a bad connection. (I had previously changed all the socketed logic as well, but that made no difference) -- I guess time will tell.The fact that you are seeing such round numbers would make me suspect you are seeing something similar ... an extra resistor left in the path (or paralleled) ... have a look at page 111 and 112 in the Parts List and Addendum doc (this was more accurate than the other manual for me as I had the "constant current relay driver sub-board". It's probably worth checking that all the relays (specifically RL1,2,3,4,5,6) are behaving as expected.Lee.

author: maginnovision
author_rank: Super Contributor
timestamp: April 12, 2019, 07:52:30 am
content: Quote from: essele on April 12, 2019, 07:32:01 amThose are the values I calibrated. Since the values were too far out for it to save I calibrated them with those offsets and attached a sticky note to the top case. I will check it all later but for now it's been about 6 hours to do the calibration and I'm ready to not hear the fan anymore, haha. Thanks for the tips though, I'll definitely check it.

author: branadic
author_rank: Super Contributor
timestamp: April 16, 2019, 08:11:28 pm
content: Received a first 3D printed part for the cover as well as the boards today. After 3h manual solder job here is the result, a first board is assembled. Next step: check the board on a 180V power supply. If this works as expected I will perform the modifications on my front panel pcb and check if this works too. If that's the case I can finallize the cover.-branadic-

author: maginnovision
author_rank: Super Contributor
timestamp: April 16, 2019, 09:50:00 pm
content: Looks pretty good. Looking forward to seeing it lit up.

author: coromonadalix
author_rank: Super Contributor
timestamp: April 16, 2019, 10:00:07 pm
content: +1 incredible job, i hope it gives a good result for you

author: wolfy007
author_rank: Frequent Contributor
timestamp: April 17, 2019, 01:15:58 am
content: Looks fantastic! Are you going to paint the white masking black?

author: branadic
author_rank: Super Contributor
timestamp: April 17, 2019, 05:57:30 pm
content: This white printed part is for evaluation only. I'm working on a more simple and reproducable solution.Tested the display board today on a 128V source and it works as expected by now, I can address each segment through a 10k resistor on A1 - A11 and a 100R resistor on segment 'a' to segment 'i'.These are the resistors that needs to be replaced on the front panel pcb (10k instead of original 1k and 100R instead of original 1k8/2k7/4k7 depending on the size of the segment), while the 100k as well as the 330k, that are connected to a -70V rail from a BZX75 zener, need to be removed.The original transistors 2N5401 need to be replaced by 2N6520 and the 2N5550 by 2N6517 for higher collector-emitter-voltage.However, the board needs a small redesign as the LEDs for the units are not on the proper place compared to the printed mask. Seems like there is some issue within Eagle with vector fonds. Also I need to change some footprints, since I was planing 1206 resistors before but use BAV303 instead that come in a MicroMelf package.Furthermore I'm thinking about deleting the two squares as they are of no value. They are not controlled but directly connected to the supply rails, which looks like they provide some basic load to the rails? Could find some pictures where they are slightly visible.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: April 18, 2019, 08:34:17 pm
content: Redesigned the boards and ordered them today. It will take about 2 weeks to have them here.I also came across a solution for the cover. It turned out that original films with silver layer for pcb exposure are still available as a service for a small budget (DIN A4 for 18€ incl. shipping, enough space for 8 displays). So I've ordered one DIN A4 print. This makes the spacer between pcb and cover more simple so that it can be fabricated using FDM printers and a black filament.The only drawback is that I have to wait again for everything to arrive.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: April 19, 2019, 08:24:13 am
content: Nothing at least that I want, as I like to have the segments crystal clear. Shining through a pcb will decrease intensity and blur everything.Will use the free days on easter to modify the front panel pcb as described above and to install the display prototype for a second sanity check (power up the board in it's final application).-branadic-

author: maginnovision
author_rank: Super Contributor
timestamp: April 19, 2019, 09:12:34 am
content: I like that idea with the film and a simpler spacer. The other one had a lot of small fine details that would be tough to print reliably. If you do have a chance to test it please take a picture!

author: branadic
author_rank: Super Contributor
timestamp: April 19, 2019, 03:55:54 pm
content: Front pcb modifications done. As described above, some resistors were replaced with new value (blue resistors) or removed and some of the transistors replaced as well. Board was already cleaned, so next step is to solder in LED display board and test it.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: April 19, 2019, 09:10:44 pm
content: And what do you know? It's working. Winner, winner, chicken dinnerOkay, for some reason one digit is a bit dim, need to check why, but the gas discharge display replacement is working. No magic smoke escaped. I'm very happy with that. Here is a first impression. So I'm on the right track and can go on this way.-branadic-

author: maginnovision
author_rank: Super Contributor
timestamp: April 19, 2019, 09:51:43 pm
content: That looks good. I think the 2 LEDs per segment was good. Once you have a filter and mask it'll look really good. The "thumbnails" look close to a real display.

author: coromonadalix
author_rank: Super Contributor
timestamp: April 20, 2019, 02:20:01 am
content: woah congrats, maybe a resistor(s) value to tweak for the dimmer display, but wowYou may have some future buiseness loll sell some kits ??

author: essele
author_rank: Frequent Contributor
timestamp: April 20, 2019, 06:56:26 am
content: Wow - impressive work!Would a solder stencil be another low cost option for your ‘film’? I’m not sure how easy they are to cut, and they would presumably need to be sprayed black, but might be worth looking into.

author: branadic
author_rank: Super Contributor
timestamp: April 20, 2019, 07:04:31 am
content: Thanks for the congrats. No, a solder stencil won't work as the circles in "d", "B" and "%" as well as the triangle in the "A" would be missing. Thus I think the film glued to a spacer with adhesive spray is the best and economical way to make the mask. It is light-thight and reflects all details.I don't think the dim digit is because of resistor values as it moves depending on the settings. Need to dig into that.So now I need to wait for the new boards to arrive as well as the film and the switches.By the way, this is exactly what I was looking for:https://www.toppress-siebdruck.de/de/leistungen/diffusorfolien.html-branadic-

author: maginnovision
author_rank: Super Contributor
timestamp: April 20, 2019, 04:17:14 pm
content: Quote from: branadic on April 20, 2019, 07:04:31 amYou're not kidding, that is literally what you needed. With that the spacer will be much more reliable allowing you to just have holes for the small designators. They even have your pcb on the home page, haha. Hopefully that dim digit issue isn't a huge time sink.

author: branadic
author_rank: Super Contributor
timestamp: April 21, 2019, 10:31:43 am
content: Can someone with Datron 4000A please post a picture how the binding posts are mounted to the front panel? I have a unit with the binding posts one the back, simply putting them to the front doesn't work as the holes in the front panel are to big. Is there an additional board the binding posts are mounted to? I pretty much appreciate any support as I like to have the binding posts on the front of the unit. Thank you very much.-branadic-

author: Johnny10
author_rank: Frequent Contributor
timestamp: April 21, 2019, 11:58:29 am
content: Simply mounted to front panel.

author: branadic
author_rank: Super Contributor
timestamp: April 21, 2019, 12:21:03 pm
content: That doesn't work for me. The holes in my front panel (Datron 4000A) are 0,7 inches in diameter, while the plastic washers of the binding posts are only 0,6 inches. The drill holes on the picture you uploaded are much smaller. So at some point the may have changed the front binding post mounting like having an extra pcb, since the holes in my unit are original, visible by the nickel coating also on the walls of the holes and there is a Datron sticker above the front terminal holes saying "Rear Output".-branadic-

author: essele
author_rank: Frequent Contributor
timestamp: April 21, 2019, 12:32:13 pm
content: My 4000A is exactly the same as the picture, mounted directly onto the front panel.I've actually got a rear terminal 4200 hopefully arriving on Tuesday (glutton for punishment), so I can see what holes are beneath the panel once it arrives.

author: Johnny10
author_rank: Frequent Contributor
timestamp: April 21, 2019, 12:39:54 pm
content: Page 38 of Service manual shows a shoulder on the plastic part of post.

author: branadic
author_rank: Super Contributor
timestamp: April 21, 2019, 01:19:29 pm
content: See the difference?-branadic-

author: Johnny10
author_rank: Frequent Contributor
timestamp: April 21, 2019, 03:13:29 pm
content: You know I have always wondered what the 4 screw inserts were for on the mainframe of the Datron.Just behind the input posts.Those holes are sized to go around input jacks.The 4 screw holes are for mounting a board.With input jacks attached.I imagine in a similar way to Datron 1062 DMM input posts.

author: Johnny10
author_rank: Frequent Contributor
timestamp: April 21, 2019, 03:37:51 pm
content: Your type Terminal Board can be found in the Datron 4708 Service ManualLayout Drawing Number 480640-1.2 Sheet 1 Datron Instr. 1989Comes up as Page 428 on my PDF Viewer

author: maginnovision
author_rank: Super Contributor
timestamp: April 21, 2019, 03:56:21 pm
content: From my 4000.

author: maginnovision
author_rank: Super Contributor
timestamp: April 21, 2019, 03:58:19 pm
content: Two more of the input board.

author: Johnny10
author_rank: Frequent Contributor
timestamp: April 21, 2019, 04:11:06 pm
content: Gonna be a lot of sore backs tonight from hefting around the Datron 4000 units !

author: branadic
author_rank: Super Contributor
timestamp: April 21, 2019, 04:29:37 pm
content: Thanks, that's what I was expecting to see. So I simly need to use a FR4 board with the proper drills and a steel sheet with the proper drills and painted black to make a poor man's front panel mounting. The wires on my unit are soldered to the binding post, so no real need to reproduce the board.-branadic-

author: essele
author_rank: Frequent Contributor
timestamp: April 23, 2019, 07:53:47 pm
content: Just for completeness, this is the front panel of my new rear-terminal 4200 ... you can see the smaller holes, so hopefully this will be an easy rework.

author: essele
author_rank: Frequent Contributor
timestamp: April 25, 2019, 06:09:56 pm
content: Interestingly I've just opened up my original 4200 and it seems to have the cut-outs the same as yours branadic, with the terminals mounted on an internal board.It is actually a bit easier to work with since you can remove the front panel more easily ... although obviously makes the move from rear terminals to front terminals a bit tougher.

author: branadic
author_rank: Super Contributor
timestamp: April 25, 2019, 06:30:34 pm
content: Thanks, I will think about how to solve this, the simple way or the professional way (reproducing the board as shown on the pictures).BTW: Got mail this morning, the new display boards are on their way, so they should receive within the next two weeks. The repro film print should receive within the next days and I also had a phone call with toppress-siebdruck today and should get an offer for 10 prints tomorrow?The redesigned plastic covers are also in production, this time using FDM printer with white filament instead of DLP printer. So the calibrator will be in working condition for the metrology meeting in june, except that I won't get it adjusted.A propos adjusted, anyone out there with experience on this? As far as I know Mickle T. got his Datron 4000A calibrated to linearity <0.1ppm. I already contacted him and asked him to share his experience on that, but he seems to be offline on this board for quite some time-branadic-

author: maginnovision
author_rank: Super Contributor
timestamp: April 25, 2019, 06:42:52 pm
content: The calibration routines are not terribly complicated but you need another source and a null detector. I faked it by using a meter since the Prema has <20pA bias but a 335D should allow you to do most of everything. The linearity is just adjusting 10V FS vs 10V. I thought about getting one but I don't really want to spend the money for just this. I got a quote for 1K for Cal(w/adjust) but he needs to talk to the lab to make sure they're still capable as they haven't done one in years.

author: branadic
author_rank: Super Contributor
timestamp: April 25, 2019, 06:51:30 pm
content: So if I get you right I could use one of my LTZ1000 with 10V +/-0.1% and a calibrated meter such as 3458A or K2002 to adjust FS?-branadic-

author: maginnovision
author_rank: Super Contributor
timestamp: April 25, 2019, 07:00:19 pm
content: Just measure the voltage, you don't actually apply anything. They specify a lot of expensive gear but if you don't mind a small offset due to bias current I think it's ok.. You just set it to output voltages and enter in the actual value. Linearity says you should clear all memories though so need linearity, coarse gain then standard Cal of setting zero, trimming 10V ref then calibrate individual ranges. If I had access to those I would do Cal using both meters to get it as close as possible.

author: essele
author_rank: Frequent Contributor
timestamp: April 25, 2019, 08:25:38 pm
content: Nobody in the UK seems to want to reply to my messages about a 4000A or 4200 calibration.For the 4000A would it work to hire a calibrated 3458A for a week, which looks to be available for a few hundred quid, and do it with that?The 4200 seems like a more complicated beast.

author: maginnovision
author_rank: Super Contributor
timestamp: April 25, 2019, 09:13:25 pm
content: Quote from: essele on April 25, 2019, 08:25:38 pmI think a good meter will get you very close. Once my 1082 comes I'll check it against my ltz1000s and if they're pretty close I'll use it to see how far my 4000 is from it and compare to Prema. A fluke 335 dialed in by a good meter would really would be a good tool for this but I don't personally think it'd be worth it. The offset due to bias current should be stable.I had similar problem getting a response even to get a couple of datron 1062/72 calibrated. Most who responded said they didn't have the equipment.Tektronix and simco were the only ones to offer a quote without saying they couldn't do it.

author: branadic
author_rank: Super Contributor
timestamp: April 26, 2019, 07:14:26 pm
content: Received an offer for the printed light-scattering films today, the print is 15€ per display. The "real repro film" is only 18,50€ incl. shipping and includes prints for 8 displays. Mh... will wait to check their quality before I step forward to the more expensive but for sure higher quality solution.Also received two FDM printed frames today. Hopefully the pcbs arrive soon.By the way: I was interested in noise of the Datron 4000A so I measured low frequency noise today with output set to 10V.-branadic-

author: maginnovision
author_rank: Super Contributor
timestamp: April 27, 2019, 05:34:21 am
content: Looks pretty good. Was that after 4 hour warm up? I'm pretty excited to see how displays look. Did you ever figure out the dim digit issue?

author: branadic
author_rank: Super Contributor
timestamp: April 27, 2019, 08:02:55 am
content: No, not 4h only half an hour, but the picture doesn't change between turning the unit on and half an hour later.I'm also excited to see how the display turns out.The dim digit is most likley due to timing settings from the controller and presumably wanted for the gas discharge display. Depending on the range choosen the dim digit changes position, but it's not a problem of my display board. I will change the resistors to overall higher current through the LEDs to make it a big brighter, there is still enough reserve. In the pictures shown I used the DLP printed frame with a printed paper on top that is fixed with polyimid tape. Doesn't look to bad by now.By the way, I'm using Kingbright KPHM-1608SECK.-branadic-

author: doktor pyta
author_rank: Frequent Contributor
timestamp: April 27, 2019, 08:24:19 pm
content: Thanks branadic,You just proved that Your idea is not only feasible but nice looking!

author: branadic
author_rank: Super Contributor
timestamp: April 27, 2019, 09:13:48 pm
content: Dziękuję bardzo-branadic-

author: wolfy007
author_rank: Frequent Contributor
timestamp: April 29, 2019, 01:41:32 am
content: Does look pretty good doesnt it.Might have to look at this for my 4700 projects. I think one of them may have a dodgy display but havent started working on it yet to confirm the problem.

author: feedback.loop
author_rank: Frequent Contributor
timestamp: April 29, 2019, 05:13:16 am
content: The dim digit seems to be a real problem. Any ideas how to fix it?Also there seems to be some light leaking through the divider into the adjacent segments.

author: branadic
author_rank: Super Contributor
timestamp: April 29, 2019, 09:53:53 am
content: I don't think it's a real problem. As far as I can remember you wasn't lucky with your solution either and it needed a lot of changes. With my approach I wanted the unit to be as original as possible, with only minor changes to the hardware.So this solution is better then having no display at allI will wait for the new display boards to arrive and install both of them to see what's the actual situation on my calibrator. I then plan to increase the overall current through the LEDs by changing the resistors.The light leaking is due to the plastic frame made fabricated with DLP, the white material it's made of being slightly transparent for the light, the fact that none of the parts is glued together without space in between and that I'm currently using a printed paper on top, while I'm waiting for the repro film to arrive.Solution:It's possible to paint the DLP part black or to use a black FDM printed material to avoid light leackage. Furthermore I think with the repro film instead of a printed paper sheet things will improve as well. However, a black epoxy molding compound as the frame directly molded to the surface of the pcb would be best, but it doesn't make sense for such small quanities.And last but not least, glue everything tight together.-branadic-

author: coromonadalix
author_rank: Super Contributor
timestamp: April 29, 2019, 10:17:40 am
content: Quote from: branadic on April 29, 2019, 09:53:53 amyess indeed, better than nothing, great work

author: feedback.loop
author_rank: Frequent Contributor
timestamp: April 29, 2019, 05:54:33 pm
content: Quote from: branadic on April 29, 2019, 09:53:53 amYou seem to be a bit defensive. I did not mean to diminish your approach, and I did not mean to compare which one is better. Yes, my approach has problems. I do not like the result. Your approach is arguably better. But this dim digit, in my view, is a problem. It would be nice to come up with a solution if possible. Of course, any working display is better than no display.

author: branadic
author_rank: Super Contributor
timestamp: April 29, 2019, 06:36:14 pm
content: Please don't understand my response as an attack on you, I simply had in mind that the OLED displays where also quite dim, despite your big effort in reverse engineering the display protocol. I pretty much liked and followed your video with big interest. Sorry if you got my statement wrong.However, if it turns out that it's really due to (wanted) timing of the multiplexed segments I have no chance to bring them all up to the same brightness with this approach. I can only increase overall brightness. But since the more dim digit walks depending on the setting I currently see no solution. I wouldn't call it a problem but a drawback. Need to investigate on that when the new boards arrived and both have been installed.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: May 06, 2019, 06:11:59 pm
content: After waiting forever I today received new display boards as well as 3D printed black frames. Board now has mounting holes for the frame. Interestingly the resistor boards for investigation on NOMCA resistor networks for LTZ1000 circuit that have been ordered long before still haven't arrived.Time to solder some diodes.-branadic-

author: maginnovision
author_rank: Super Contributor
timestamp: May 06, 2019, 06:31:38 pm
content: Does that picture show the printed films as well at the top?

author: branadic
author_rank: Super Contributor
timestamp: May 06, 2019, 07:00:24 pm
content: Yes, glued onto a white frame. The black frame will look much better.-branadic-

author: maginnovision
author_rank: Super Contributor
timestamp: May 06, 2019, 08:40:05 pm
content: Looks really sharp. As for dim figure might be practical to use some small buffers or latches if it is a timing issue.

author: branadic
author_rank: Super Contributor
timestamp: May 11, 2019, 05:23:34 pm
content: Finallized two displays, that will be installed next week together with the buttons that should arrive.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: May 14, 2019, 11:56:30 am
content: Received my buttons/switches today. Many thanks. Seems like I have something to solder tonight.-branadic-

author: maginnovision
author_rank: Super Contributor
timestamp: May 24, 2019, 09:57:22 pm
content: Ever get one of the new displays installed? I received my new buttons a few days ago and now it's much nicer and easier to use without a flaky button.

author: branadic
author_rank: Super Contributor
timestamp: May 25, 2019, 07:57:23 am
content: Yes, buttons and both displays are installed, but I felt like there was no interest in any update here. The repro films are glued to the printed spacers and finally I glued a sheet of paper in between to get it diffuse. The Datron is up and running, but I had no time to further investigate on the dim digits and won't have the time before MM2019. I also need to test the difference between black and white spacer, but that's a story for after MM2019.-branadic-

author: maginnovision
author_rank: Super Contributor
timestamp: May 25, 2019, 08:42:26 am
content: Ah, ok. Well I'm very interested. Not only do I have the calibrator but I have many Datron meters: 1 x 1082, 1 x 1072, 3 x 1062 LS101, and 3 x 1062. I already put my perfect spare display in the 1082 and the original version of your replacement display would rival 1 or 2 of mine for clarity.

author: essele
author_rank: Frequent Contributor
timestamp: May 25, 2019, 10:39:09 am
content: I'm also interested to see how it's going ... I'm in the lucky position of having three calibrators all with working displays, but I'm in the market for a 1081 so it's always good to know if there are viable options for replacing broken displays.

author: branadic
author_rank: Super Contributor
timestamp: May 25, 2019, 11:09:05 am
content: As I said, both displays are working. If you guys are interested in, I have boards, printed spacer with attached repro film left. So if you want to test the boards yourself simply leave me a pn.-branadic-

author: feedback.loop
author_rank: Frequent Contributor
timestamp: May 26, 2019, 06:57:30 am
content: The dim digits seem to be a timing issue. Looking at the schematic I see that the inter-digit blanking strobe depends on the comma strobe. I noticed on your photos that digits with active comma (segment "i") are dim. Somehow it did not matter for the gas discharge display, but it does matter for the LED.By the way, notice the capacitors between the segment logic-level outputs and the transistor drivers. Effectively they differentiate and produce short pulses during transitions. I guess that was done to start the process in gas discharge displays. Perhaps they are not needed for to drive LEDs and can be removed (shorted)? However that can change the peak and average LED current, and might require changing some other parts like current limiting resistors and such. I am not sure this can help with the dim digits though.

author: branadic
author_rank: Super Contributor
timestamp: May 26, 2019, 07:57:25 am
content: Thanks for sharing your analysis and good to know that you come to the same conclusion, that was also my interpretation of how this works.-branadic-

author: maginnovision
author_rank: Super Contributor
timestamp: May 26, 2019, 09:18:26 am
content: By the way I will PM or email you about a display(or two) soon. Busy days though.

author: feedback.loop
author_rank: Frequent Contributor
timestamp: June 04, 2019, 05:41:45 am
content: Any pictures of the improved display? I would love to see how it turned out without the leakage to adjacent segments.Any ideas how to fix the issue with dim digits yet?Thanks.

author: branadic
author_rank: Super Contributor
timestamp: June 08, 2019, 08:41:15 pm
content: No new pictures by now. With the new spacer there is no more leackage to adjacent segments. However, I'm not happy with the dim digits and I have no idea how to fix them without changing to much of the original circuitry, but I have confidence that it is due to a timing issue and most likely wanted or was at least no problem for the original gas discharge display.-branadic-

author: feedback.loop
author_rank: Frequent Contributor
timestamp: April 21, 2020, 05:18:48 am
content: branadic, could you share your designs? As I understand, there are three parts: a PCB with LEDS, front window with transparent symbols and a plastic spacer-divider to stop light leakage between segments. Perhaps you have some drawings that can be submitted to some manufacturers to produce those things. Where did you order them? How much do they cost? Thank you.

author: tggzzz
author_rank: Super Contributor
timestamp: April 21, 2020, 08:14:37 am
content: Quote from: branadic on April 05, 2019, 03:20:12 pmI have a sick 490x: the "4903 DC Calibration Unit" starts to work, but gets jammed in a "busy" state.How similar/different is the 4903 likely to be to the 4000?If anybody has any manuals, I'd be very interested

author: branadic
author_rank: Super Contributor
timestamp: April 21, 2020, 07:05:49 pm
content: feedback.loopI still have kits available incl. board, components, spacer and cover. A single display kit is 42.68€ plus shipping, or 85.36€ plus shipping for two displays like in Datron4000 calibrator. Honestly I expected more people to need a replacement display.-branadic-

author: feedback.loop
author_rank: Frequent Contributor
timestamp: April 22, 2020, 05:12:41 am
content: Quote from: branadic on April 21, 2020, 07:05:49 pmA bit pricey. I really like your solution except that dim section problem, and I am thinking that, perhaps, I should try to combine your solution with mine. Perhaps you remember, I have my custom display board that replaces the original display board. It receives the data from the main CPU of my 1071 meter, and I have full flexibility to display the data any way I want. The TFT displays I picked turned out to be poor. So I might just drive this display of yours. This should work great. A bit more complicated and expensive than I would like this to be, but nothing is perfect.

author: branadic
author_rank: Super Contributor
timestamp: April 22, 2020, 09:16:47 pm
content: QuoteThis are the plain costs for the components, no profit for me-branadic-

author: LaserEng
author_rank: Regular Contributor
timestamp: April 23, 2020, 07:32:04 am
content: This display replacement looks great. I would be tempted to do away with the comma drive altogether to get the same brightness on the digits as the units seem totally usable without the comma's, I would do this either by removing C20 and C26 on the front panel or R35 and R45 on the digital PCB.Before reading the cct description I though maybe the commas where using up some of the display multiplexing time for doing the comma's only and thus leaving less time for the digit display but I was wrong and it just appears to be the extra loading of having the comma on that is reducing drive to the remaining segments. Maybe the comma drive signal could be used to switch in a circuit to provide extra current but it seems less hassle to do away with the comma's completely.Another though is maybe trying to reduce the current available for the comma LED's and see if the rest of the segments get brighter, I guess dimmer comma's would be more aesthetically pleasing than having dim digits.Less than a 100 euro's for 2 displays seems a bargain to me if you consider the price of used Datron gear, ok, maybe not for the lower end Datron DMM's but definitely for the 4XXX instruments. Seems well worth the price to keep these nice instruments from the landfill.

author: branadic
author_rank: Super Contributor
timestamp: April 23, 2020, 11:39:28 am
content: It is a bargain, not to mention the time and efford I spent to get it working.Haven't though about the comma yet, but it makes sense, even though separating thousends by a comma is uncommon in Germany.-branadic-

author: guenthert
author_rank: Frequent Contributor
timestamp: April 23, 2020, 04:38:03 pm
content: Quote from: branadic on April 23, 2020, 11:39:28 amThat's slightly misleading. For those not familiar with the notation used in Germany: a comma is used as separator for decimals, the dot is (optionally) used as thousands separator (so exactly the opposite as in e.g. USA). I think Germans will forgive the usage of a dot as decimal mark (since many devices are either made or designed in the states or made/designed chiefly for that market), but might get slightly confused by comma used to group digits.

author: feedback.loop
author_rank: Frequent Contributor
timestamp: April 23, 2020, 04:49:47 pm
content: Quote from: branadic on April 23, 2020, 11:39:28 amYes, I understand, and thank you very much. I will send you a personal message.

author: branadic
author_rank: Super Contributor
timestamp: June 19, 2022, 03:25:43 pm
content: Eventually my Datron 4000A stopped working and I could hear some cracking noise before I switched it off immediately. Does someone by accident has a list of (tantalum) caps to order at digikey or the like for a full recap of the unit? Would be very helpful to make that order of all material. Thanks.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: June 30, 2022, 07:32:35 pm
content: Attached is my list for capacitors and the replacements I used, just in case someone needs a starting point.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: July 01, 2022, 08:48:07 pm
content: Updated the list, it's now in a final state.-branadic-

author: chilternview
author_rank: Frequent Contributor
timestamp: September 05, 2022, 09:04:37 pm
content: Quote from: branadic on March 25, 2019, 09:05:14 pmI'm also looking for a few of the switches for my Datrons (4000A + 4200). Can you give me the manufacturer's details?thanks!

author: essele
author_rank: Frequent Contributor
timestamp: September 06, 2022, 06:51:23 am
content: Hi,I sent the initial query to info@nsfcontrols.co.uk and they were very helpful, but you have to buy a large batch.I still have a few, how many do you need?Lee.

author: chilternview
author_rank: Frequent Contributor
timestamp: September 06, 2022, 08:24:28 am
content: Lee,I only need a few - four should be plenty. Would be most appreciative if you have any you're willing to sell.

author: FFY00
author_rank: Contributor
timestamp: November 23, 2022, 06:37:39 pm
content: RE: SwitchesI have ordered fromhttps://www.ebay.com/itm/284584941383and simply replaced their red cap with the black one from the old switch. The red cap is bigger on these switches, but the base is the same.

author: FFY00
author_rank: Contributor
timestamp: November 29, 2022, 01:17:33 am
content: I had to order more switches. The failure point is a little hook that is holding the spring internally, so they are prone to failure with age as the plastic becomes brittleAfter some search, I managed to find some clones from china. The footprint seems to match, but I haven't received mine yet.https://www.aliexpress.com/store/1390203/search?SearchText=PB86

author: chilternview
author_rank: Frequent Contributor
timestamp: November 30, 2022, 03:17:32 pm
content: You can get the switches from DigiKey ( part # EG1701-ND ). They are £3.62 each in 1 off quantities.

author: branadic
author_rank: Super Contributor
timestamp: March 23, 2023, 06:02:28 pm
content: Attached the spacer in different thickness (1 mm, 2 mm, 3 mm). Feedback.loop suggested to increase thickness to achieve more diffused segments.-branadic-

author: Scotia1982
author_rank: Newbie
timestamp: November 17, 2023, 12:04:11 pm
content: Hi, Do you still have the Kits available as I have a Datron 1071 that uses the same display.