hybridfree/eevblog-posts huggingface dataset:
Datel/GE DVC-350 Calibrator - Replacement LCD display needed - Page 1
Forum section: electronics / repair

author: mcmahongg
author_rank: Newbie
timestamp: May 02, 2018, 12:03:19 pm
content: HiAnyone know of a suitable model number and/or supplier for replacement LCD display needed for Datel/GE DVC-350 Calibrator?It's a 40-pin, glass panel type, 7-segment 4.5 digit LCD display.The LCD is driven by an Intersil/Maxim ICM7211MIPL display driverBackplane connections on Pins #1 and #25 and the pins for the rightmost digit are:a4 #22b4 #21c4 #20d4 #19e4 #18f4 #23g4 #24With decimal points *probably* on #5, #9, #13, #17.thanks for any adviceGerry

author: syzygy
author_rank: Contributor
timestamp: June 07, 2021, 10:52:59 pm
content: Hi Gerry - did you ever find a source for the glass? I'm looking now (glass is 'leaking' black), and the manufacturer (calibratorsinc.com) phones don't work, and their website seems....old.

author: mcmahongg
author_rank: Newbie
timestamp: March 28, 2022, 11:58:23 am
content: Hi - sorry I've only just seen your message. No - unfortunately I was never able to find a replacement LCD for the devcice.

author: PureZX
author_rank: Newbie
timestamp: August 11, 2022, 03:49:29 pm
content: I have a faulty Datel DVC-350. LCD looks good, in fact the unit is in reasonably good condition. Looks like it's been kept in the carry case. Battery compartment cover is damaged and wont stay in. It's been on my 'to do' shelf for quite a while as I can't find any schematics. I have a data sheet and the manual but sadly no schematics.Mike

author: coromonadalix
author_rank: Super Contributor
timestamp: August 11, 2022, 05:02:19 pm
content: i would search for ICM7211 projects, you could find an almost identical or suitable lcd ??i think you have an lcd with pins on the glassor search Ebay for used or defective units taking a gamble ??not sure datel had oem / clones variants
Datron 1061A Calibration key - Page 1
Forum section: electronics / repair

author: Ade911
author_rank: Regular Contributor
timestamp: September 14, 2023, 07:22:40 pm
content: Hello support group,Does anyone in the UK have a spare Datron 1061A calibration key I could purchase from them please before I rip the switch out and replace.Many thanks

author: Macbeth
author_rank: Super Contributor
timestamp: September 14, 2023, 08:33:29 pm
content: Check out Usagi Electric or Lockpicking Lawyer for those totally worthless keyswitch defeats. A lockpick is more fun than a genuine key.

author: meandeev
author_rank: Regular Contributor
timestamp: December 18, 2023, 09:48:31 pm
content: it´s maybe the same like in the Datron 4000/4200 calibrators: a normal Yale DC751 - as you are in UK it should be cheap as a test...

author: TheDefpom
author_rank: Frequent Contributor
timestamp: December 19, 2023, 02:53:27 am
content: I can confirm that the cal key is the same for all the multimeters and the 4700 calibrator.I actually had a key that was close, it went into the lock OK so I pulled the switch apart to figure out where to file the key to get it to work, from that I had a few more cut for my devices, I covered it in a video of mine on a 1062 if I remember rightly.attached is a photo of the key I found on the forum some time ago, it is almost the same.My key is an CH751, and the ones I had cut are a ilco N54G type.Here is the video where I pull the lock apart:

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: July 29, 2025, 03:22:16 pm
content: Defpom and the group,Thank you for the information on the Datron calibration keys.I purchased a couple of CH751 keys from a local store, Canadian Tire. I removed the cylinder from a lock on a Datron 1061 DMM, following the guidance in the video. I filed the CH751 in a couple of places to get it to work in the 1061.This picture shows the two areas that I had to file the CH751.The picture you posted was very useful.I tried the key in a Datron 4000A calibrator. It works for this calibrator too.Regards,Jay_Diddy_B
Datron 1062:  Does not go into cal mode - Page 1
Forum section: electronics / repair

author: 4thDoctorWhoFan
author_rank: Regular Contributor
timestamp: July 19, 2020, 12:54:07 am
content: Hi,I have a Datron 1062 that does not go into cal mode. The unit itself seems to work fine as the volts (ac & dc) & ohms functions appear to work. It also has the current option but I have not tested that yet. When I turn the cal key in the rear, there is no cal symbol displayed on the front panel.The key lock & the display seem to work as normal. When I turn the key in the rear, the 5V line from the key lock will toggle between hi and low but no cal displayed on the front panel. Also, when I run the self test, the display will illuminate the cal symbol as it goes through it's self test so it does not seem to be a display driver or display problem.I'm guessing it's a problem on the digital board but I would like to see what others might think. Perhaps I am overlooking something simple or perhaps someone has seen this issue before.It's not going to be a easy fix so I'm looking for the easy way out first.

author: Testtech
author_rank: Regular Contributor
timestamp: July 19, 2020, 04:55:34 pm
content: The GPIB address switch must be in a particular setting to enable CAL mode. Described in the cal manual.

author: 4thDoctorWhoFan
author_rank: Regular Contributor
timestamp: July 19, 2020, 06:08:49 pm
content: Thanks for the info but I am aware of this. I should have mentioned it in the original post. I believe all the switches have to be switched to 1.But thanks for reminding me as perhaps there is a problem with the GPIB board.

author: dacman
author_rank: Frequent Contributor
timestamp: July 20, 2020, 08:52:00 pm
content: Make sure the Cal switch is making contact. Also, those things are notorious for bad IC contacts.

author: 4thDoctorWhoFan
author_rank: Regular Contributor
timestamp: July 21, 2020, 09:01:41 pm
content: I was finally able to get it into cal mode by removing the connector for the GPIB board. The IEEE board installed in my unit is nothing like what's in the manual or what's in other peoples units that I have seen on YouTube. The board layout is totally different from anything I have seen. I will not be using this board but it's strange how different it is. Oh well, at least I can get it into cal mode now.
Datron 1062 LS101 Repair Series - Page 1
Forum section: electronics / repair

author: TheDefpom
author_rank: Frequent Contributor
timestamp: August 08, 2020, 11:56:30 pm
content: Hi All,I recently finished the repair of a Datron 1062 Multimeter (videos are posted in their own topic), and have now started the repair series on the LS101 version of the same meter, obviously the videos will be on my YouTube channel, but I will post them here too.Part 1:Part 2:

author: Nx-1997
author_rank: Regular Contributor
timestamp: August 11, 2020, 01:18:16 am
content: I also have a Datron 1062 LS101 that was giving Error OL. I fixed that issue by setting all the GPIB address switches to position 1. Mine was also giving Error 5 and another error related to ohms board. I replaced the optocouplers, and that may or may not have fixed the issues. I also have a power supply issue, bridge rectifiers and transformer get super hot.

author: TheDefpom
author_rank: Frequent Contributor
timestamp: August 12, 2020, 07:24:50 am
content: Quote from: Nx-1997 on August 11, 2020, 01:18:16 amReplace both of the bridge rectifiers, I used 2W10 to beef them up a bit.

author: TheDefpom
author_rank: Frequent Contributor
timestamp: August 13, 2020, 10:59:30 pm
content: Part 3:

author: TheDefpom
author_rank: Frequent Contributor
timestamp: October 10, 2020, 08:17:40 pm
content: Part 4.

author: TheDefpom
author_rank: Frequent Contributor
timestamp: October 10, 2020, 08:18:52 pm
content: Part 5.

author: TheDefpom
author_rank: Frequent Contributor
timestamp: October 10, 2020, 08:25:05 pm
content: Part 6.
Datron 1062 Multimeter Repair Series SN_016117 - Page 1
Forum section: electronics / repair

author: TheDefpom
author_rank: Frequent Contributor
timestamp: January 01, 2021, 01:34:42 am
content: That is right, I'm fixing another one !(Spoiler - I also design a replacement display module)Part 1:

author: TheDefpom
author_rank: Frequent Contributor
timestamp: January 18, 2021, 04:26:07 am
content: Part 2:

author: TheDefpom
author_rank: Frequent Contributor
timestamp: January 18, 2021, 04:27:15 am
content: Part 3:

author: TheDefpom
author_rank: Frequent Contributor
timestamp: February 11, 2021, 05:08:41 am
content: Part 4:
Datron 1062 Repair Series - Page 1
Forum section: electronics / repair

author: TheDefpom
author_rank: Frequent Contributor
timestamp: May 21, 2020, 03:07:35 am
content: Hi allI have picked up a couple of Datron units, this is the first video about the repairs.Datron 1062 Autocal Multimeter Repair Part 1

author: TheDefpom
author_rank: Frequent Contributor
timestamp: May 29, 2020, 05:45:53 am
content: Datron 1062 Autocal Multimeter Repair Part 2...

author: odium
author_rank: Contributor
timestamp: May 29, 2020, 07:06:08 am
content: nice guessing workwill you flash eeproms with compatible firmware versions ?cheers !

author: TheDefpom
author_rank: Frequent Contributor
timestamp: May 29, 2020, 07:10:12 am
content: I have ordered some TMS2532 from China, once those arrive I will burn them with the 1071 firmware and give it a go to see if I can get 7.5 digits out of it, failing that I have downloaded the 1062 firmware set that someone posted on the forum which has the same part numbers as the EPROMs on the digital board, so I should be able to replace the GPIB EPROM.

author: TheDefpom
author_rank: Frequent Contributor
timestamp: June 30, 2020, 01:09:41 am
content: Part 3 (I forgot to update this thread!)

author: TheDefpom
author_rank: Frequent Contributor
timestamp: July 06, 2020, 12:04:17 am
content: Part 4:

author: TheDefpom
author_rank: Frequent Contributor
timestamp: July 18, 2020, 04:10:50 am
content: Part 5:

author: TheDefpom
author_rank: Frequent Contributor
timestamp: July 18, 2020, 04:13:17 am
content: Part 6:
datron 1071 error7 Seeking help - Page 1
Forum section: electronics / repair

author: MuShan
author_rank: Contributor
timestamp: April 23, 2024, 02:57:32 pm
content: 1071 will not output error 7 when the resistor option is not inserted, but error 7 will occur when the resistor option is inserted It gives me a headache

author: MuShan
author_rank: Contributor
timestamp: April 23, 2024, 02:58:46 pm
content: When inserting the AC and current options separately, there is no error message of error 7, and this machine is very strange. If only the current and resistance options are not inserted, an error message of error 8 will be displayed

author: MuShan
author_rank: Contributor
timestamp: April 23, 2024, 03:03:15 pm
content: The original 1071 communication option communication gear will display error ol

author: MuShan
author_rank: Contributor
timestamp: April 23, 2024, 03:04:55 pm
content: The original 1071 AC voltage option would display error ol in the AC gear, but now the 1061a AC voltage option is being used

author: TheDefpom
author_rank: Frequent Contributor
timestamp: April 24, 2024, 04:52:10 am
content: I may be remembering this incorrectly, but try changing the 2 wire - 4 wire switch.. I know in one position it will result in an error during self test, I don't remember the error number though, it MIGHT have been 7.Also if it has the front rear input switching check for that being wrong too.I have done several repair videos on the Datron multimeters, you should probably watch them for some tips.The first thing is definitely to replace ALL the electrolytic capacitors, the most important to do are on the bootstrap supplies on the analogue PCB, there is a row of blue caps along the front side of the board, they are ALWAYS bad, but ideally you replace all of the caps, I have seen bad power supply caps take out the main diode bridge which then shorts out which then overheats the transformer.

author: MuShan
author_rank: Contributor
timestamp: April 24, 2024, 11:50:13 am
content: Quote from: TheDefpom on April 24, 2024, 04:52:10 amI have watched your videos many times and have replaced all tantalum electrolytic capacitors with solid-state capacitors, as well as which electrolytic capacitors I have switched to in the 2W situation

author: MuShan
author_rank: Contributor
timestamp: April 24, 2024, 12:29:03 pm
content: I suspect it's a problem on the DC board
Datron 1081 Meter and Negative Ohms - Page 1
Forum section: electronics / repair

author: MaxFrister
author_rank: Regular Contributor
timestamp: August 17, 2019, 03:12:39 am
content: I have a Datron 1081 7-½ digit multimeter that I restored recently. Mostly it seems to be working great. However….If I let it sit with the power off for a week or so and then turn it on and place it into resistance mode, it often shows negative ohms (e.g., -247,334). Nothing I do from the front panel seems to reset it. DC and AC voltage seem to work okay. Turning it off and back on always clears the problem.I’ve dealt with intermittent failures before but the one trial per week makes this a challenge. The meter has been completely re-cap’d and a new battery installed (amongst other things).I’m looking for suggestions as to what to try next...

author: maginnovision
author_rank: Super Contributor
timestamp: August 17, 2019, 06:20:24 am
content: Have you done the calibration on the ohms board?I'm pretty certain it's the same as 107x(possibly 106x). If you'd like I can check tomorrow, butthat's where I'd start. Actually it doesn't matter since the service manual is available. Also pages 26, 27, and 28 have a lot more info. Just start at the relay and work your way through.
Datron 1082 multimeter firmware issue ? - Page 1
Forum section: electronics / repair

author: macfly
author_rank: Contributor
timestamp: May 02, 2020, 03:48:20 pm
content: Hello,I observed a strange phenomenon on my Datron 1082 DMM:Here you can see it, measuring a stable 10V source after one hour warm-up:The 1Hz-filter and the 'Hi-Res'-mode is activated.To have a more stable result, I tried the 'block-mode', in this case with n=10.What then happended makes we wonder:The conversion result ist 25 (!) Digits lower. If I switch the block mode off, the result willbe same as before. Changing the number of block-mode cycles to e.g. 20 has the same result.For me this looks like a firmware error … but I am not sure.My Datrons firmware version:My question to other DATRON 107x- and 108x-user:Does your Datron do the same ?Thanksmacfly

author: dacman
author_rank: Frequent Contributor
timestamp: May 02, 2020, 06:13:27 pm
content: I suspect a bad IC contact or a bad IC.

author: picburner
author_rank: Frequent Contributor
timestamp: May 02, 2020, 06:26:05 pm
content: If you want to do a checkhereis the firmware of a Datron 1082, but I don't know if it is the same version.

author: macfly
author_rank: Contributor
timestamp: May 02, 2020, 09:08:25 pm
content: Hello picburner,thanks for the link. I have just no EPROM programer and the right EPROM type, but it's worth a try.@ dacmanI agree with you. A hardware issue is most likely.But the point is, that both measure-modes use the same hardware.Regards,macfly
Datron 1281 Meter Repair Help - Page 1
Forum section: electronics / repair

author: starjohn
author_rank: Newbie
timestamp: March 21, 2014, 08:07:42 am
content: I am working on a Datron 1281 meter.DC voltage calibration at 10v functions ok, but the Internal source calibration failed.This Meter has the following errors after Internal source calibration.Error codes:2202 1KV Range zero magnitude test (P028).2192 100V Range zero magnitude test (P021).2162 10V Range zero magnitude test (P006).What would cause these errors?Is there anyone that has experience in repairing these instruments?

author: jjohnson
author_rank: Newbie
timestamp: July 24, 2014, 02:21:04 pm
content: I also have a Datron with the same issues to include error codes 2222 and 2224. I was hoping you may have found a solution to your first three. What I have found in looking through my unit is that at the lower ranges 10v and below i have some random spuratic noise on my guard in certain areas of the board not sure if it suppose to be like that but it seems to come from the bootstrap area and cant seem to pin point the bad component if you can help please let me know.

author: pelule
author_rank: Frequent Contributor
timestamp: April 12, 2015, 07:12:51 pm
content: QuoteHow did you do the internal source calibration?

author: Krampmeier
author_rank: Regular Contributor
timestamp: January 08, 2023, 03:33:47 pm
content: You can start the internal source calibration by entering the EXT CAL menu and selecting QUIT. The meter will then ask if you want to trigger the internal source cal or quit. After that, you can set the cal due date.
DATRON 4000 with FAIL 3 - what to do? - Page 1
Forum section: electronics / repair

author: geangu
author_rank: Newbie
timestamp: September 12, 2017, 06:01:27 pm
content: I have a DATRON 4000 that displys FAIL 3 and the front lanel is locked. What is this and how to fix it? Help please.

author: tggzzz
author_rank: Super Contributor
timestamp: September 12, 2017, 08:42:47 pm
content: Fortunately there are somehintsto befound, including on this website.

author: Johnny10
author_rank: Frequent Contributor
timestamp: September 12, 2017, 09:27:24 pm
content: Fail 3I will try and give you information from the Service ManualRight now I am without power and internet, we were in the path of Irma.

author: Johnny10
author_rank: Frequent Contributor
timestamp: September 12, 2017, 09:46:20 pm
content: Section 4.5 part

author: Johnny10
author_rank: Frequent Contributor
timestamp: September 12, 2017, 09:53:02 pm
content: I know this could be better but with just an iphone hotspot I am at a disadvantage for the next few days.

author: geangu
author_rank: Newbie
timestamp: September 13, 2017, 11:49:15 am
content: Thank you tggzzz, but nothing about Fail 3 out there, and no manual for Datron 4000 to find.Thank you Jonny10, I will try to dig into it and I really appreciate you helping even while hit by Irma. Wish you well and be safe. Would be possible to scan the manual and post it somewhere? Thanks again.

author: geangu
author_rank: Newbie
timestamp: September 13, 2017, 04:04:57 pm
content: Got it, the problem was a register chip MC14021 defective. Now it works. Still would be nice to have the manual if possible.Thank you for help

author: Johnny10
author_rank: Frequent Contributor
timestamp: September 13, 2017, 04:18:54 pm
content: That was a quick repair!Did the keyboard start working also?

author: geangu
author_rank: Newbie
timestamp: September 13, 2017, 04:30:22 pm
content: Yes, all is good now.

author: essele
author_rank: Frequent Contributor
timestamp: February 01, 2022, 05:17:54 pm
content: Just to add to this for other people's future reference...I also had a FAIL 3 on my 4000A (which had been fine for a number of years) ... after a bit of round the houses troubleshooting and realising there was a second lot of power supplies in the schematics, I found it was actually caused by a shorted tantalum on the in-guard power supply board.It was causing zero output on the -15V(2) and the -10V(2) supplies. This situation doesn't seem to trigger any power supply monitoring and manifests itself as a lack of serial comms between the reference divider and the analog interface, hence the FAIL 3.... bizarrely I missed the in-guard power supply board when I was re-capping, rectified now and all is good.

author: Chris56000
author_rank: Frequent Contributor
timestamp: February 01, 2022, 10:41:39 pm
content: Hi!This any help?https://www.google.com/url?sa=t&source=web&rct=j&url=https://xdevs.com/doc/Datron/4000A/Datron4000_Calibration_and_ServicingHandbook.pdfPS!Despite the enormous file size, the file for the 4000/4000A on k04BB is only half–a–dozen pages of it – please use the one I've linked above!Chris Williams
Datron 4000A -- can someone check something for me? - Page 1
Forum section: electronics / repair

author: essele
author_rank: Frequent Contributor
timestamp: August 03, 2019, 03:10:28 pm
content: Hi,Sadly I'm having some more problems with my Datron 4000A ... this time I'm seeing a complete lack of load regulation on the low voltage ranges (10V and lower), and before I rip open my newly calibrated machine I was just checking to make sure I wasn't doing anything stupid and now have totally confused myself with how the terminals are supposed to be connected.Both the 4000A and 4200 manuals say that the I+ and I- terminals are connected to the "internal power circuits" and Hi and Lo are the remote sense terminals, and if you have local sense enabled then these are internally connected (as you might expect.)However ... with local sense on, I cannot get a sensible output from either the 4000A or a 4200 if I used the I+ and I- terminals, but the Hi and Lo terminals are fine. Further on in the manuals it actually shows the use of Hi and Lo for simple two wire connections ... seemingly contradicting the earlier comments.If it was just the 4000A then I'd be suspecting a relay problem (since the terminal is definitely connected in current mode), but as I see the same issue on the 4200 then it's probably 'as designed' but it would be good if someone could just do a quick test for me.Very simple test: if you connect a multimeter to I+ and I- in DCV mode, set the 4000A to 10V output ... do you get the 10V output?For me I don't get any output ... if I move the negative line down to the Lo terminal then it's fine, and obviously using both Hi and Lo is fine. I just want to see if that's standard behaviour.Many thanks,Lee.

author: maginnovision
author_rank: Super Contributor
timestamp: August 06, 2019, 12:27:28 am
content: The answer to your test is yes I do. 2 and 4 wire modes, although in 4 wire not exactly the same voltages on each pair.

author: essele
author_rank: Frequent Contributor
timestamp: August 06, 2019, 05:51:10 am
content: Thanks Maginnovision — more to look at when I pull it apart again.
Datron 4200 cal ram not writing - Page 1
Forum section: electronics / repair

author: essele
author_rank: Frequent Contributor
timestamp: May 18, 2019, 04:18:16 pm
content: I have yet another Datron calibrator challenge...My 4000A and 4200 are in for calibration, the 4000A is apparently fine but the 4200 was out of spec but isn’t accepting the new cal values... they said ‘not keeping them’ (it may be different as the symptoms weren’t really clear on the phone call.)The lab have suggested it might be the battery so they are trying to get me a new one, but I’m struggling to see how a battery problem would cause problems with writing cal data. There were no failures before so it’s obviously able to read something sensible so I’m assuming it’s retaining data.I’m guessing it’s actually a ram issue or a problem with the surrounding logic ... but I won’t know for sure until it comes back and I can experiment a bit (if the new battery doesn’t fix it.)Does anyone else see how the battery could cause this issue?(I will probably look at putting an FRAM board together, although I probably should have done that before getting them calibrated ... not sure if I could read the old ram without causing problems.)

author: maginnovision
author_rank: Super Contributor
timestamp: May 18, 2019, 04:41:50 pm
content: The only thing I can think of is it was outside the allowable tolerance but that should be apparent to them.
Datron 4700 Calibrator Scope Waveforms For Reference. - Page 1
Forum section: electronics / repair

author: TheDefpom
author_rank: Frequent Contributor
timestamp: July 03, 2021, 06:13:07 am
content: Hi All,I just fixed my Datron 4700 again today, the issue I had was on the reference assembly PCB.I grabbed various screen shots from the scope at various stages and different test points, I thought I would share them here in case they help someone else that is trying to diagnose problems on their reference PCB in the future.Test points used in the pictures are TP4, TP5, TP3, LK8 and TP12, I also have some on the collectors of Q19 and Q20, refer to the image names to know which is which.I listed the test points in the channel order.

author: TheDefpom
author_rank: Frequent Contributor
timestamp: July 03, 2021, 06:23:15 am
content: I was originally thrown by the flip flop output at TP5 being inverted, that was a symptom not a cause (pic 3), this was due to the reference voltage being shorted out and that resulted in the flip flop turning on both halves of the flip flop at the same time, as you can see in the attached image, which shows Q25 and Q27 base's both turning on at the same time ! (pic 1)I traced this down by (unfortunately) cutting a track that feeds the reference to the flip flops and injecting my own supply to isolate the reference, that instantly corrected the flip flop fault, but the units fault was still present.I then traced the fault back to the voltages on the collectors of Q19 and Q20, which were very different from each other, despite being mirrored circuits ! it turnout out that Q20 wasn't fully turning on to output -11VDC, and so it was never turning the JFETs off, this is what was shorting out the reference. (pic 1)
Datron 4708 firmware need - Page 1
Forum section: electronics / repair

author: Cage03
author_rank: Newbie
timestamp: April 09, 2020, 05:57:39 pm
content: Hi, Have anybody Datron 4708 eprom dump file?

author: coromonadalix
author_rank: Super Contributor
timestamp: April 09, 2020, 08:43:07 pm
content: At KO4BB website you have some manuals and some stuff, but no eeprom dumphttp://ftb.ko4bb.com/getsimple/index.php?id=manuals&dir=06_Misc_Test_Equipment/Datron

author: doktor pyta
author_rank: Frequent Contributor
timestamp: April 10, 2020, 08:53:46 am
content: If You won't find anything within a week I will try to prepare dumps for You.

author: Cage03
author_rank: Newbie
timestamp: April 10, 2020, 10:59:38 am
content: I only found the dump file 4808. I would be very grateful for your help.

author: doktor pyta
author_rank: Frequent Contributor
timestamp: April 11, 2020, 12:03:27 am
content: OK, I'm faster than I thought.Below You will find dump of M18 EPROM.http://rfscientific.eu/sites/default/files/articleextra/eprom_datron_4708.zip

author: doktor pyta
author_rank: Frequent Contributor
timestamp: April 14, 2020, 12:36:04 am
content: @Cage03Can You share some photos, details about Your repair?Was Your M18 EPROM corrupted?

author: Cage03
author_rank: Newbie
timestamp: April 14, 2020, 04:26:19 am
content: Today I will continue to repair and give here some more info and photos.

author: Cage03
author_rank: Newbie
timestamp: April 14, 2020, 03:28:37 pm
content: My M18 eprom has a fault, 8 bytes are OK, another 8 bytes always have 0 on the second bit.Other differences are due to different firmware versions, but 4708 is running.There is still some defect on the AC board because the Reference Dividercontrol voltage is only from 0 to 8 V and when I remove the AC board is to 20 V.

author: doktor pyta
author_rank: Frequent Contributor
timestamp: April 15, 2020, 09:52:56 am
content: First of all check output of M3 optocoupler on REF Divider board.It carries 16kHz reference clock for PLL in AC synthesizer.When this signal is not present, the amplitude and frequency of AC are behaving very strange.

author: perdrix
author_rank: Frequent Contributor
timestamp: April 15, 2020, 06:12:13 pm
content: IIRC there are two programmable devices on the 4808 CPU board. I assume this is for the main ROM - M18? Has anyone ever grabbed the content of the M3 address decode PAL?Where did you find that ROM image please?ThanksDavid
Datron 4805 multifunction Calibrator - No DC output voltage. - Page 1
Forum section: electronics / repair

author: CGMtesting
author_rank: Newbie
timestamp: May 07, 2020, 07:16:51 am
content: Dear All,I am new to this forum and thanks for accepting me.I have an issue on my Datron 4805. My problem is that for some reason, I have no DC voltage as output....The output is always 0Vdc.Does anyone have any idea where to check because I have no schematics to start.Thanks.

author: Grandchuck
author_rank: Super Contributor
timestamp: May 07, 2020, 05:49:33 pm
content: Here is a link for manuals for two similar models:https://www.eevblog.com/forum/testgear/service-manuals-for-datronwavetek-4808-multifunction-calibrator/

author: CGMtesting
author_rank: Newbie
timestamp: May 08, 2020, 05:44:19 am
content: Hi Grandchuck,Thanks a lot for helping me.I found the fault .....found 2 dry joints on Q6 (JE340) and Q7(JE350) of the Vdc card (with orange circuit board ejectors). On the collector I had to find +38Vdc and -38Vdc respectively.Thank you.

author: Grandchuck
author_rank: Super Contributor
timestamp: May 08, 2020, 02:06:11 pm
content: Nice work! You are welcome.
Datron 4808 Fail 9 - shorted tantalum bead capacitor but with 10V margin - Page 1
Forum section: electronics / repair

author: perdrix
author_rank: Frequent Contributor
timestamp: March 10, 2022, 04:15:15 pm
content: Simple problem - either the +15V or -15V in-guard supply is overloaded. Time to play hunt the tant!And of course the part that had gone short-circuit was a 10uF 25V tantalum bead capacitor on the +15V rail. It had a voltage rating of > 50% over the rail voltage. I thought this should have been sufficient to protect against the classic problem with these parts (failing short when little or no voltage over-rating). I replaced it with a 35V part which is >100% headroom. Should I just put it down to "old age"?Your thoughts?David

author: fzabkar
author_rank: Super Contributor
timestamp: March 10, 2022, 04:45:13 pm
content: Yes, I've seen hundreds of failures in these caps. I saw one burn like a match head while testing a PCB in the workshop.

author: TheDefpom
author_rank: Frequent Contributor
timestamp: March 10, 2022, 11:00:51 pm
content: I did a big repair series fixing my Datron 4700, I replaced every single 25V tantalum in the unit with a 35V, I suggest you do the same...Also re-cap the main power supplies whilst you are at it, there could be excessive ripple coming through, don't rely on testing the caps low voltage testers don't tell you everything, measure the supply ripple with a scope.

author: bdunham7
author_rank: Super Contributor
timestamp: March 10, 2022, 11:31:33 pm
content: I recently repaired a Fluke calibrator and replaced more than 100 tantalum caps because of these failures and I think that margin is not enough. I used Kyocera AVX 50 volt caps for almost every instance, the only exceptions being a few caps larger than 10uF in less than 10 volt circuits that were not available higher than 35V. I replaced a number of the larger tantalums with electrolytics and had no issues.

author: TiN
author_rank: Super Contributor
timestamp: March 11, 2022, 12:33:14 am
content: Just replace them all. Burning down calibrator or even your home not worth the tantalum cost.

author: Testtech
author_rank: Regular Contributor
timestamp: March 11, 2022, 10:33:43 pm
content: What color is the bad part? Yellow, blue, something else?

author: perdrix
author_rank: Frequent Contributor
timestamp: March 12, 2022, 01:28:09 am
content: It was yellow (FWIW).PS TheDefPom suggested that I re-cap the main power supplies. Unless there's an easy way to get those boards out without complete disassembly I'm very wary of attempting this. Even removing the rear panel is a pain as there's not enough length in the leads soldered to the connectors to allow you to pull it more than about 1" to 2" away from the rest of the calibrator.D.

author: Testtech
author_rank: Regular Contributor
timestamp: March 12, 2022, 04:04:25 pm
content: The reason I asked about the color, I have seen many more of the blue tants fail than the yellow, but they all are suspect.I guess I am going to have to bite the bullet and recap my 4800A.Would you have a parts list to share?Thanks,
Datron 4920 - Page 1
Forum section: electronics / repair

author: NiaDebesis
author_rank: Frequent Contributor
timestamp: April 10, 2021, 08:40:41 pm
content: Hi,I have in my hands a good 4920 with full options, mv, DC, and other things.Unfortunally it is broken, on the left display says "Error UR" with I didn't find in the manual and the right display is gone.Thinking about a recapping and checking the PSU and the linear regulators.But anyone know what Error UR means?Best regards

author: TheSteve
author_rank: Unknown
timestamp: April 11, 2021, 04:22:08 am
content: Error UR - is completely normal. It means "Error Under Range" - all ranges need a minimum input voltage to display a reading. It is documented in the manual.

author: NiaDebesis
author_rank: Frequent Contributor
timestamp: April 11, 2021, 08:10:21 am
content: Yes yesterday I found out this because the second display is dead.I have lost cal data so it tells me to press some buttons that I didint know off.For cal data it means only the calibration data of the procedure right? because I can recalibrate it

author: picburner
author_rank: Frequent Contributor
timestamp: April 11, 2021, 02:12:53 pm
content: If your right display is broken you can try mysolution, I tried it with a Datron 1271 but it should work on your Datron 4920 too.

author: TiN
author_rank: Super Contributor
timestamp: April 13, 2021, 02:46:41 am
content: Recalibration of 4920 is lot of fun, unless you work in high-end metrology lab

author: chinapp
author_rank: Contributor
timestamp: March 06, 2022, 03:05:52 pm
content: could you share more pics inside ? I wanna see what's inside the mV option
Datron / wavetek 4808 15 V guard fail - Page 1
Forum section: electronics / repair

author: Patest
author_rank: Newbie
timestamp: September 05, 2023, 12:44:36 am
content: I experienced this problem with my Datron 4808 and my wavetek 4808 all within one month, the main line voltage was from two different sources, one in my lab, the other at a customer site.Are they worth fixing?

author: ManateeMafia
author_rank: Frequent Contributor
timestamp: September 05, 2023, 03:12:49 am
content: 15v rails like to die from shorted tantalum capacitors. I have seen this a few times now on 4808, 4800, and 4700.Some may argue that you should only replace the dead ones but so far I replaced all on each rail that failed. One calibrator had a domino effect where replacing one capacitor caused the next dead one to smoke. After a few iterations, I just bulk replaced them.Also, the inguard PS can also be damaged. I would inspect it for any burnt parts. It is also possible that an inductor or two has failed. These are yellow and tend to become crispy after a short.. Inspect all boards that can be removed.I also increased the voltage rating on the tantalums from 25v to 35v.
DC-DC converter AN8083S IC - but from where it draws energy? - Page 1
Forum section: electronics / repair

author: pplaninsky
author_rank: Regular Contributor
timestamp: June 18, 2022, 06:56:41 pm
content: Hi,I am really puzzled by the application circuit shown in this datasheet.That is an old DC-DC IC, but what supplies energy to that circuit.My best guess is that PVcc should be hooked to a power supply/battery, which is not shown on the circuit diagram...

author: fzabkar
author_rank: Super Contributor
timestamp: June 18, 2022, 07:54:27 pm
content: Are you mistaking the  battery symbol for a capacitor?

author: Echo88
author_rank: Frequent Contributor
timestamp: June 18, 2022, 11:45:21 pm
content: Ah indeed, easy to miss: On PVCC theres a battery symbol above the Clk-Pin.

author: gamalot
author_rank: Super Contributor
timestamp: June 19, 2022, 07:24:19 am
content: The circuit diagram is indeed a bit hard to read, but it brings me back to the good old days when everything came with a circuit diagram.

author: pplaninsky
author_rank: Regular Contributor
timestamp: June 19, 2022, 11:59:54 am
content: Thank you!Good catch. Energy conservation principle savedNo busting required ...

author: pplaninsky
author_rank: Regular Contributor
timestamp: June 19, 2022, 12:00:58 pm
content: btw, did you notice the strange symbol for electrolitic capacitors?Something like 3 Zs next to each other.Haven't seen that before as well.

author: gamalot
author_rank: Super Contributor
timestamp: June 19, 2022, 12:13:48 pm
content: Quote from: pplaninsky on June 19, 2022, 12:00:58 pmThat's Japanese style.https://sound-au.com/beginners.htm
DC DC converter ID - Page 1
Forum section: electronics / repair

author: Audiorepair
author_rank: Frequent Contributor
timestamp: November 28, 2023, 11:43:03 am
content: Hi,anyone help ID this converter?It has 12v pin 2, powers a Sennheiser radio mic receiver.Edit: Receiver has a Power On tactile switch.

author: Haenk
author_rank: Super Contributor
timestamp: November 28, 2023, 01:32:56 pm
content: Did you ask Sennheiser? Some of the "established" manufacturers are still happy to help. SPL even sent me some spare parts from their inventory.

author: fzabkar
author_rank: Super Contributor
timestamp: November 28, 2023, 06:51:10 pm
content: http://markingcodes.com/search/c/775XC9247B75CER-G, Torex, 16V Driver Transistor Built-In PWM/PFM Step-down DC/DC Converter, marking 775+XX, USP-6C:https://product.torexsemi.com/system/files/series/xc9246.pdf

author: Audiorepair
author_rank: Frequent Contributor
timestamp: November 28, 2023, 07:40:08 pm
content: Thanks, not sure why I couldn't find that now.
DC-DC Converter ISL98602IRAAZ not outputting voltage - Page 1
Forum section: electronics / repair

author: canadaboy25
author_rank: Regular Contributor
timestamp: February 25, 2021, 12:13:37 am
content: Hey everyone,I have a T-Con board from an LED TV that is not working. There is an ISL98602IRAAZ that does not seem to be doing anything. There is a testpoint labelled 1.2V beside the chip which has no voltage. I have read that the ISL chip on these boards often fails so I ordered some replacements. However, after replacing the chip, I still get no output. I replaced the chip a second time in case one of the cheap Chinese chips I bought was bad. Still no output.Making things more difficult, there is no datasheet available for this chip online other than a pinout with short pin names.I have 12V input on pins 5,30,31,36,37,381.22V on pin 254.7V on pin 244.4V on pin 18The enable pin has 0V which seems like a problem to me. I tried tracing the pin out on the board but cannot find where it goes as it is a multilayer board. I tried putting 3.3V on the enable pin but there was no change.I'm not sure what half of the pins do which makes troubleshooting the problem quite difficult.Does anyone have any ideas on things to check for?Thanks

author: amyk
author_rank: Super Contributor
timestamp: February 25, 2021, 01:27:57 am
content: The 98602 is the "recommended replacement" for the 97622, 97522, 98604, and several others whose full datasheets are available and likely very similar, so I would look to those for inspiration and learning.

author: fzabkar
author_rank: Super Contributor
timestamp: February 25, 2021, 07:58:25 am
content: Did you test the resistance to ground at the 1.2V output? Perhaps there is a shorted load.

author: canadaboy25
author_rank: Regular Contributor
timestamp: February 25, 2021, 08:52:45 am
content: Quote from: amyk on February 25, 2021, 01:27:57 amYes, I noticed that as well. I have been trying to reference the 98604 datasheet and some of the typical application circuitry looks similar. However, it is tricky since many of the pin names do not resemble each other.Quote from: fzabkar on February 25, 2021, 07:58:25 amYes, I forgot to mention that I tested the resistance between the 1.2V rail and ground and there is 1K of resistance.After analyzing the circuitry closer, it appears that there is a 3.3V output at the very top left of the picture I posted. This output has 75 ohms of resistance to ground. This seems a bit low to me but I am not sure. Also, I was able to find that the enable pin of the chip is connected to the 3.3V rail through a resistor. It seems strange to me that the enable pin would be tied to a voltage rail that is generated by the chip itself. Perhaps the 3.3V rail is supposed to be a standby rail of the chip and they just tied the enable to it in order to have the chip always active?
DC-DC Converter MES1515M - Page 1
Forum section: electronics / repair

author: evzone
author_rank: Newbie
timestamp: December 26, 2022, 09:21:32 am
content: Hello all,I am looking for a special DC-DC converter module (MES1515M) that has failed in my external air-conditioning inverter unit. I found its datasheet, here is the link:http://pwrgmall.co.kr/DATAS/es_shop_product/Microsoft_Word_-_MES1515M_R1-0.pdfUnfortunately this part is not sourced in any of the well known suppliers like Mouser, Digikey, RS Components etc. It looks like it is only available in Korea but I can't find a way to order it from Europe.Do you know any alternative part that can replace this DC-DC converter?Thanks
DC Electronic Load Banana Jack/Plug Converter - Page 1
Forum section: electronics / repair

author: Ordinaryman1971
author_rank: Frequent Contributor
timestamp: November 29, 2020, 03:46:58 pm
content: I've watched Signal Path/ Noise Path video TNP #2 - Quick Repair of a Mechanically Damaged Agilent E3647A 60V Dual Channel DC Power Supplyand I've noticed the bananafy connector on his Electronic Load.I've found one on Tindie:https://www.tindie.com/products/iohippo/dc-electronic-load-banana-jackplug-converter/They are currently out of stock.Wanted to ask if anybody has them made already, maybe have some spare ones I can buy or maybe somebody made a pcb that has the same functionality that I can possibly order.

author: joeyjoejoe
author_rank: Frequent Contributor
timestamp: December 09, 2020, 01:48:18 am
content: Should be quite easy to design. What is the spacing of your banana jacks?

author: Ordinaryman1971
author_rank: Frequent Contributor
timestamp: December 28, 2020, 08:45:40 pm
content: Got some from ebay.https://www.ebay.com/itm/DC-Electronic-Load-Banana-Jack-Adapter-Board/154246499734?hash=item23e9cecd96:g:hb8AAOSwZ2FfSeuRVery nice design. Really recommended.They are also priced right. Tindie guys charge over $10 for pcb...I am really happy with those.And here is a picture with all dimensions.
DC Negative fuse will blow when I connect amplifier to mains outlet. - Page 1
Forum section: electronics / repair

author: Makila
author_rank: Newbie
timestamp: February 02, 2020, 04:41:38 pm
content: Hi,I have a 13.8 Volt DC linear power supply that I use to provide power to my ham radios.I also have a valve linear amplifier for 144 Mhz that has it's chassis connected to mains ground.When I connect the two together, the 30 Amp fuse in the negative line to the radios will blow.So... I investigated to find out how this is happening and discovered that the DC voltage on the Negative terminal of the power supply has 24.6 volts above ground potential, and being a 40 Amp supply, the negative fuse blows due to the amplifier, connected to the radio through various cables being at mains ground potential.So the power supply really needs to be at ground potential, the negative line is not connected to ground. There is no circuit diagram for this power supply, a QJE QJ-1840SC, and I was thinking - can I tie the negative to mains ground as it is currently isolated?Any thoughts welcome.Many thanksSteve

author: aqibi2000
author_rank: Regular Contributor
timestamp: February 02, 2020, 06:39:20 pm
content: Use a lead acid battery with a fuse in series to power it up and report back the outcome:

author: fcb
author_rank: Super Contributor
timestamp: February 02, 2020, 06:49:16 pm
content: Sounds like your PSU is not floating.I would expect that even if it is not floating, at least the 0V output would be tied to ground, especially as a google search shows the PSU has a cigarette lighter output on it as well. Probably worth taking the lid of the PSU.

author: TheMG
author_rank: Frequent Contributor
timestamp: February 02, 2020, 08:28:47 pm
content: Sounds like the unregulated positive rail of the power supply is somehow shorted to chassis ground or something.This could be due to a broken insulator on one of the pass transistors on the heatsink or the rectifier diodes, or something as simple as a connection/wire touching chassis somewhere.With the power supply off and capacitors discharged, measure resistance between positive of main filter capacitors and the chassis ground. It should be an open or high resistance.

author: Makila
author_rank: Newbie
timestamp: February 03, 2020, 08:23:29 am
content: Measuring the resistance between the ground and positive rail is about 9 Mohms so is quite high. The DC voltage is rather odd when measured against the ground, which is 25 VDC on the negative connector and 11.5 VDC on the Positive connector. So why would the positive have a closer potential to ground than negative?Is there a link anywhere to get a circuit diagram of this device, QJE QJ-1840SC? I have found nothing on it apart from pictures.Thanks Stev
DC offset ± 48V situation on Yamaha AX 750 - Page 1
Forum section: electronics / repair

author: xavlaur
author_rank: Contributor
timestamp: June 02, 2021, 02:23:00 pm
content: Hello!On the diagram below I checked as diodes all transistors Q619 ... Q643 and they are ok but I always have either -48V or + 48V starting with the collector of Q619 and up to the base of Q640 / 641. Something escapes me, Any idea?I attached measurements, I think the problem passes "through" the input (IC601A), at different restarts DC offset appears or as -40V, or as + 40V as I noted above, with orange I put the voltages when DC offset occurs "-", with green when it goes on "+". The voltages are lower compared to the normal ones because I supplied them ballasted by 2 lamps 48V / 5W (they light up poorly) because Q635 or Q636 heat up one by one (Ubc = close to supply voltage due DC offset), depending on how it goes, on + or -.Something seems irregular with the voltages on the IC601A inputs / outputs.Somehow it is unclear to me the role of IC601A combined with (Q602 & Q603)

author: shakalnokturn
author_rank: Super Contributor
timestamp: June 02, 2021, 04:49:45 pm
content: IC601 is the "DC servo", check both supplies to it (I only see a note for the negative rail), then check it isn't open looped somewhere (R601, R727, R602, R604).

author: xavlaur
author_rank: Contributor
timestamp: June 03, 2021, 12:00:56 pm
content: Due on pin 7 are -5V, IC601A internally it seems to be out of order. I'll come back with more details.

author: xavlaur
author_rank: Contributor
timestamp: June 04, 2021, 12:54:31 pm
content: Q632, Q635, Q636 replaced with equivalents.Q640, 641, Q642, Q643 replaced on the radiator but not connected on the board. If I connect them, the consumption increases and I have nothing to measure. If not connected, the emitter from Q635, Q636 becomes asymmetrical to the output rail. In this topology I think it must be 2 resistant as a load against the table.All transistors Q602 .... Q651 checked as diodes, are ok.The 48V / 5W bulbs - in series with ± 50V power supply, connected after electrolytes - light up very weakly but they also supply the functional channel (on the mainboard there is no power separation between the channel).### As additional information, with R603 = 47K disconnected (IC601A seems ok now with R603 disconnected), the system starts at + 40V (bases Q635, Q636) so that after 20 seconds it starts to decrease rapidly (in about 3 seconds) until + 30V, then to quickly reverse the polarity (in about 2 seconds) decreasing to -40V, a value that remains constant for the rest of the measurements. Once stabilized at -40V, Q621 seems saturated.I changed C616 = 100µF / 16V to 100µF / 100V, but no any changing in the above transient mode.C603 47µV / 16V and C605 3.3µF / 50V are harder to reach, I haven't changed them at the moment. I don't see any other electrolytes to delay reversal.The timing of the reversal is not related to protection relays triggering.R673 = 220 ohms slightly discolored but at the nominal level.