hybridfree/eevblog-posts huggingface dataset:
VISHAY PRECISION RESISTORS EBAY - Page 1
Forum section: electronics / general

author: VNUTDENYER
author_rank: Contributor
timestamp: May 11, 2020, 01:37:25 pm
content: Quick question. Are those 1k 2ppm .01% Vishay resistors from Poland worth $12 ea. to build good Hamon divider for 100-12000 ohm use checking 6-1/2 digit dmm? Heading to ER now from CCP virus confinement so sorry about lack background info.

author: RandallMcRee
author_rank: Frequent Contributor
timestamp: May 11, 2020, 03:40:07 pm
content: I would say not.I have found at least two sources (but not at arbitrary values) of precision resistors that provide similar specs for $3 per resistor. Look around.So, only worthwhile if you *must* have a certain value. For a hamon divider that is not the case.Thanks,Randall

author: ArthurDent
author_rank: Super Contributor
timestamp: May 11, 2020, 04:18:46 pm
content: I have purchased several orders of those precision SFERNICE/Vishay resistors on eBay from sm-poland7 in Poland and I found them to be first quality. His feedback is 100%. If you buy from him go with the economy shipping at $6USD and not the faster $39 shipping! He is a reliable supplier of precision resistors and I am just a very satisfied customer.Those resistors were used in my LTZ1000ACH standard that has been on 24/7 for over a year. My standard agrees with the USA Cal Clubs standard and my HP3457A 6.5 digit DMM.See photo below of my standard with the inner metal cover off and without the foam shield around the LTZ1000ACH.

author: VNUTDENYER
author_rank: Contributor
timestamp: May 11, 2020, 09:01:29 pm
content: Thanks for seller vote, will look some more but wanted R300 for full scale HP3478 ranges to start (set of 10/12 makes 30, 50, 100,150, 300,450, 3k and lots more). Hoping to start with at least 0.1% and then test/match for tighter. Did not see US shipping for $6 which would be fine. Still looking for better way to series/ parallel them selectively than banana plugs.
Need a couple pages from the HP 5062C manual! - Page 1
Forum section: electronics / general

author: 5065AGuru
author_rank: Frequent Contributor
timestamp: May 11, 2020, 05:09:32 pm
content: Hi,I have a manual but it does only goes up to serial prefix 1836A and therefore does not have the manual changes for the 1844A series.Actually I have one page I photocopied years ago.The top of the page reads:MANUAL CHANGES MODEL 5062C and 5062C OPT. 010 Page 3It shows steps 10 thru 23 of an alignment procedure.Bottom of the page reads:Figure 1. Troubleshooting AdjustmentsI need a copy of pages 2 and 4 that have the rest of the steps.Can anyone help?Thanks,Corby
Got the Symmetricom Mark V working! - Page 1
Forum section: electronics / general

author: notfaded1
author_rank: Frequent Contributor
timestamp: May 10, 2020, 08:59:51 pm
content: I mentioned this guy before in one of my Cesium repair threads... I won it in an auction really cheap but initially it wouldn't lock onto any satellites. After taking apart I was happy to see it's LO inside! I found some docs that referred to a version of it's GPS unit called the Trimble Force 22. I knew it could work without keys so I got into the menu system zeroized the existing variables and reset the system. I've very happy to report it's locking onto birds now! The amazing thing is some initial measurements show it to be much more stable frequency wise than I think any of my other GPS or GNSS DO's! This thing may become my new house standard over all my other nice DO's.Look at that local oscillator it has! Nice score I think.Bill

author: notfaded1
author_rank: Frequent Contributor
timestamp: May 10, 2020, 09:09:03 pm
content: It has boards inside that say Truetime so it makes me think there was some sharing between commercial and industrial base hardware. I recognized the keyfill port on the front and at first thought it might not be capable of working without keys... but alas it does. This actually makes sense because what would you do in the field if you had to zeroize your keys? Just be lost? That makes zero sense despite there usually being massive redundancy.
Spectracom Wireless TimeView 210U  - Page 1
Forum section: electronics / general

author: tkamiya
author_rank: Super Contributor
timestamp: May 19, 2020, 06:23:55 am
content: I ended up with a working Spectracom Wireless TiveView 210U.One issue.... this thing only communicates with wireless and requires a specific transmitter. To make it worse, this must be an early version. There is no other (such as serial) connections mentioned on current manuals. Looking inside thinking there has to be a port inside and radio part is a daughter-board, I found out that isn't the case. There are several jumpers and connectors but there are no obvious way to identify what they are used for and what the possible combinations would mean.So far, I have no luck in finding service manual. Brochures and user manuals are everywhere but they don't mention anything internal. Following them, all I can get is something to display but second digits keeps blinking. This is an identification of not talking to a server.Initially, I was hoping some way to use this as remote display on ntpd network or possibly have a format converter and network around the house. I'm stuck at this point.Does anyone here have experience of this piece of equipment?
5MHz 1MHz 100kHz CCHB-74 Frequency Rubidium Standard - Page 1
Forum section: electronics / general

author: syau
author_rank: Frequent Contributor
timestamp: May 08, 2020, 10:15:05 am
content: Spotted a rare item in evilbay;5MHz 1MHz 100kHz CCHB-74 Frequency Rubidium Standardhttps://www.ebay.com/itm/233582126352NOSI am in no way affiliated with this item or the seller.
SZA263 references in  the Fluke 515A portable calibrator - Page 1
Forum section: electronics / general

author: rhb
author_rank: Super Contributor
timestamp: May 07, 2020, 07:10:05 pm
content: Would better voltage references improve the accuracy?I got a 515A yesterday on a whim while picking up a Tektronix 577 curve tracer. The switch knob on the front was broken off and the NiCad pack is shot. However, it does work on line power.I opened it up for a look and found it uses a pair of SZA263 references. The DC reference is under a small plastic cover while the AC reference is exposed. These have 1980 date codes.At spec, it's quite good for a DMM calibrator. Despite old age and neglect, the 100 V output reads 100.0033 V on my better 34401A just probing the output with test leads, no guard, etc. The 515A spec is 30 ppm. I don't recall the 34401A spec, but I know from the USA Cal Club Round 2 that it's well within spec on the 10 Vdc range.I've attached the datasheet for the 515A for convenience.Have Fun!Reg

author: Kleinstein
author_rank: Super Contributor
timestamp: May 07, 2020, 07:20:34 pm
content: The SZA263 is a good reference if combined with good resistors and with well adjusted current. For higher grade it is used with on oven.A well aged one should also be stable by now.The reference is likely not the limiting factor, especially if used at a relatively constant temperature. It is probably more the other parts that limit the accuracy.

author: chuckb
author_rank: Frequent Contributor
timestamp: May 08, 2020, 05:24:24 am
content: Many years ago I bought a group of six F515 calibrators. They looked pretty bad with broken knobs so I did not work on them right away. These were manufactured around 1975.Last year we started to clean them up and 4 of the 6 units were in excellent shape. The hermetic Wirewound resistors were still very close, even after 45 years! The 10meg resistor is Caddock film on ceramic. I salvaged to the Zeners and the hermetic resistors for another calibrator project.The 10V DC out was stable to 2 ppm over a week of monitoring on a HP3458A. The noise was as low as the normal F732A voltage standard.The weak point in the design is the small pcb with the voltage and resistance trimmer pots on it. The edge connectors are intermittent after all this time. We soldered some jumpers across the pins and everything was stable.These are well built units, simply amazing.
Messed up FE5650A - can someone help me? - Page 1
Forum section: electronics / general

author: tkamiya
author_rank: Super Contributor
timestamp: May 06, 2020, 02:27:08 pm
content: I *just* took a shipment of ERC-130 10MHz Rubidium standard. Inside is FE5650A with no options. It just has a dash after 5650A. The frequency was little off so I adjusted what I thought was an EFC, except it wasn't.I hope you see a row of 4 10 turn trimmers. I adjusted the second from the bottom one. The end result was, kt lost lock. By carefully walking back, I was able to obtain a lock. So my guess is either it's a PLL loop gain or PLL amplitude adjustment. Frequency drifts UP a lot, but that could be due to unit sitting in warehouse for a while.I read what I can find on Service manuals, but none of the explanations go into the second board. Does anyone know what this pot is supposed to do, and what adjustment criteria is? My PLL experience is from 20 years ago with 4044 chips. I know gain and amplitude affects stability and speed.By the way, re-reading, I now know the proper way of adjusting frequency.Thank you.

author: martinr33
author_rank: Frequent Contributor
timestamp: May 07, 2020, 11:46:29 pm
content: If you are lucky, it might affect the lock window.When these units start up, they hunt above and below the lock frequency. Once the cell is warm, the oscillator locks in and stacks up the zeroes on your frequency counter.It could be that that pot moves the window. If you move it too high - it never locks.So you might try putting the output on a frequency counter, and watching the startup behavior. It might be that the pot will center the hunting zone for you.

author: tkamiya
author_rank: Super Contributor
timestamp: May 08, 2020, 12:27:50 am
content: You are right. When I had that pot on extreme, it never locked. I eased back little by little and it is locking now.If this is like a traditional PLL, there should be another pot to change the speed of scan. When set too fast, it misses it and comes back, and does this ringing thing. When set too slow, it takes forever.Also, there should be a gain setting, similar to what you are suggesting.I wish I could get my hands on manuals. So far, I found some that talks about top board but not the middle board.Many years ago, when I opened back of ANY TV, there was a circuit diagram and brief adjustment chart. We should bring that back.
UBlox Max-M8W-0-10 Questions - Page 1
Forum section: electronics / general

author: Gandalf_Sr
author_rank: Super Contributor
timestamp: May 07, 2020, 01:28:20 pm
content: 1. Updating firmwareI have a Max-M8W-0-10 system and I'm connected to it via U-Center but I can't find where in U-Center I can find out what the current version is on the module if I go Receiver > Action > Get Information, where does the result get stored or displayed?2. It seems that the Max-M8W-0-10 can "talk" in NMEA so can anyone:a. point me to documentation as to how I can get the module to output NMEA messagesb. a way to connect a CAN bus hardware adapter (after all NMEA2000 is just CAN isn't it?)Thanks in advance.
GPS Breakout PCB using MAX-M8W-0-10 - Page 1
Forum section: electronics / general

author: Gandalf_Sr
author_rank: Super Contributor
timestamp: October 19, 2019, 06:16:08 pm
content: I to try out the UBlox Max-M8W-0-10 module and couldn't find a ready-made module on PCB for it so I threw a quick PCB design together that uses a super Cap for backup (seems to work well) and implements an active antenna power supply in this case 3.3V.I've had time to play with this and it works quite well.Eventually I want to migrate to using I2C comms but for now, I am able to plug it into a UART connection and send setup commands via U-Center to obtain the information - I'm running it from a USB-serial port connector on my PC.There is some interest in the design so I've attached some documentation; a schematic and a rough user guide. PM me if you want a PCB.

author: awallin
author_rank: Frequent Contributor
timestamp: October 19, 2019, 07:49:38 pm
content: on linux, gpsd should work for receiving the messages over serial porthttps://gpsd.gitlab.io/gpsd/index.htmlthere's a python client that can parse the messages if you want lat/lon/height or ecef etc.it also works as an ntp refclock driver, for accurate PPS you should have the PPS wired to the DCD pin of the serial port.gpsd comes with ubxtool which is specific for ublox receivers, to read and write settings.

author: jimmc
author_rank: Frequent Contributor
timestamp: October 19, 2019, 08:16:55 pm
content: I've only used the 7 series but the simplest way I found (on Windows) was to download u-center (https://www.u-blox.com/en/product/u-center) and look at the command strings it produced.Having them to reverse engineer made it a lot easier for me to understand the UBX-CFG commands in the user interface manual.Jim

author: Gandalf_Sr
author_rank: Super Contributor
timestamp: October 19, 2019, 08:42:20 pm
content: Thanks, if I make configuration changes using u-center, e.g. baud rate, will they be lost on a power cycle or is there some way to save settings to flash? Further reading indicates that the UBX-CFG-CFG command saves all the settings as power up defaults.

author: Gandalf_Sr
author_rank: Super Contributor
timestamp: May 07, 2020, 10:49:03 am
content: This design has been running for a while and someone asked me for a PCB so I'm raising it from the dead. A user guide and schematic are now attached to the first post.I have some spare, bare PCBs if anyone wants one, PM me.
Optical probe for oscilloscope - Page 1
Forum section: electronics / general

author: Unknown
author_rank: Unknown
timestamp: May 05, 2020, 08:17:56 pm
content: Back in January Elektor published a "Optical Probe for Oscilloscopes" project:https://www.elektormagazine.com/articles/optical-probe-for-oscilloscopesIt's a photodiode with a couple of op-amps.My question - how is this better than just hooking a photodiode (or small solar cell) directly to an oscilloscope?I've successfully measured video latency with small solar cells and an oscilloscope - CH1: solar cell and camera, CH2: solar cell on display; flash a light at the camera, measure time between Ch1 and Ch2 spikes.I don't think the result is quantitative in either case. So why bother with the opamps?

author: FenTiger
author_rank: Regular Contributor
timestamp: May 05, 2020, 09:21:47 pm
content: Impedance matching? The photodiode sees a roughly zero Ω load due to the virtual ground created by IC3A, while IC3B is configured to drive a 50Ω cable.

author: Unknown
author_rank: Unknown
timestamp: May 05, 2020, 10:58:15 pm
content: Quote from: FenTiger on May 05, 2020, 09:21:47 pmMaybe. Would that improve the frequency response?I mean, why bother impedance matching? A solar cell (or I presume a photodiode) seems to drive an oscilloscope directly just fine.

author: FenTiger
author_rank: Regular Contributor
timestamp: May 06, 2020, 01:35:09 am
content: Quote from: Dave92F1 on May 05, 2020, 10:58:15 pmI don't know. I'm just guessing, and hoping somebody will tell me why I'm wrong.

author: JohnPi
author_rank: Regular Contributor
timestamp: May 06, 2020, 04:23:44 am
content: Bandwidth.A scope may have ~ 20 pF or input capacitance in parallel with 1 MΩ -- giving a time constant of about 20p*1M = 20 us. The photodiode (which has additional capacitance, further reducing the BW) generates a current and this takes some time to charge the 20 pF capacitance. When the light turns off, it takes some time for the 1 MΩ to discharge the capacitance. The final voltage is the photocurrent * 1 MΩ, or the VF of the photodiode itself (about 0.6 V). An opamp appears to short the photodiode current to the virtual ground -- thus that current doesn't have to charge any capacitance -- the opamp does the work of driving the output and also the virtual ground through the feedback resistor, giving an output voltage of Iphotodiode* Rfeedback.You can see this yourself -- touch and remove a scope probe to a battery or power supply -- you will see a fast rising edge when you make contact, but an exponential decay when removed (it may be quite noisy when you do this manually, but you will be able to get a few clean traces)

author: tggzzz
author_rank: Super Contributor
timestamp: May 06, 2020, 07:00:58 am
content: Search terms that will help: photovoltaic mode, photoconductive mode, PIN photodiode, transimpedance amp.Which type of design is most appropriate depends on objectives and constraints.

author: tanveerriaz
author_rank: Contributor
timestamp: May 06, 2020, 06:46:57 pm
content: response time of solar cell and photodiodes are difference .
Furuno GT88 Timing GNSS receiver - Page 1
Forum section: electronics / general

author: jpb
author_rank: Super Contributor
timestamp: May 11, 2019, 09:23:59 pm
content: I don't know how new this is, I've not seen it before, but Furuno now has a GT88 as an improvement on the GT87.It looks a good candidate for a GPSDO.https://www.furuno.com/en/products/gnss-module/GT-88#SpecI can't find any boards the equivalent of the GT-8736C, the evaluation kits for the GT87 are silly money so I guess the same will be true of the GT88. Hopefully a much cheaper board (a GT-8836??) will appear soon.

author: WPXS472
author_rank: Regular Contributor
timestamp: May 06, 2020, 01:46:08 pm
content: Just saw this. I am looking for a board for the GT-88 as well. I will keep an eye out, and if I find one, I'll post here.

author: Nuno_pt
author_rank: Frequent Contributor
timestamp: May 06, 2020, 02:51:20 pm
content: They've the complete kit as an evaluation board, see here: <https://www.furuno.com/en/products/gnss-module/GF-8805>It has an Furuno GF-88 with OCXO, if it was cheap around $100-$150 would be a good bet to buy a evaluation kit, the P/N is VF-84 or VF-85

author: jpb
author_rank: Super Contributor
timestamp: May 06, 2020, 05:06:30 pm
content: Quote from: Nuno_pt on May 06, 2020, 02:51:20 pmUnfortunately I don't think it would be under $1000 - the plain evaluation kit without OXCO is £722 inc VAT :https://www.digikey.co.uk/product-detail/en/kaga-electronics-usa/VN-882/62-1385-ND/10249019I think that they won't produce a cheap evaluation board like that for the GT87 as that was a motorola board replacement and there probably isn't the same demand now.
Need a cal unit for the lab. DC/resistance or more - Page 1
Forum section: electronics / general

author: Zenwizard
author_rank: Regular Contributor
timestamp: May 01, 2020, 08:30:56 pm
content: I have a batch of bench meter and TM500 meters I need to check in and calibrate and adjust for the lab to bring them in to spec. I have a repaired Fluke 5200A and the 5205 amp to go with it so I think I have AC covered. But I need something for DC and resistance. Don’t mind spending a bit of money if it is on something fluke or similar quality. Is there a multi-unit that does DC and resistance? Might also need current at some point as well but the primary focus is DC/AC/resistance.
USA Cal Club RF division - Page 1
Forum section: electronics / general

author: rhb
author_rank: Super Contributor
timestamp: May 29, 2020, 02:45:31 am
content: I have the following:0 dBm 50 MHz HP calibrator30 dB by 1 dB JFW attenuator200 kHZ to 1 GHz diode noise sourcewhich I'm willing to devote to helping calibrate RF gear, I don't have cals on this stuff, but I intend to develop that as I get my lab set up. However, I have a contact with a commercial RF cal lab who has offered to do a cal, so we might actually be able to get NIST traceability.At the moment, the best I can do is to test against my current gear. I feel confident that the noise source is flat to within +/- 1 dB and expect that once I test with my 8970B I should be able to calibrate it to within 0.5 dB allowing for uncertainties.What else should be included in an initial package? Ultimately, I'd like to have L & C standards, but this seems to me a decent start.Have Fun!Reg
Comparing PX/FX Using Series Standard Cells - Page 1
Forum section: electronics / general

author: VNUTDENYER
author_rank: Contributor
timestamp: May 04, 2020, 11:47:30 pm
content: Comparing the CalClub PX and FX references by stacking standard cells in series seems doable without a 7/10 divider. I plan to measure short term noise/drift on 4 standard cells and pick best three to "add" to PX, getting it close enough to compare with FX using HiZ range on HP3478A. Assuming PX/FX NOT HARMED by adding voltage source in series with Gohm level meter, are there any other reasons not to try this??? Also sourcing suitable parts for 10/7 divider for direct comparison. Can't decide between Hamon and binary type construction (Hamon for easier resistor matching and binary for "self cal" (whatever that means). Or maybe add all 4 cells to 3v REF103 and compare with PX? Comments, suggestions???

author: bob91343
author_rank: Super Contributor
timestamp: May 05, 2020, 05:50:07 am
content: It might help if you explain what PX and FX mean.

author: TiN
author_rank: Super Contributor
timestamp: May 05, 2020, 06:26:30 am
content: Unless your cells are saturated type, in very stable thermal chamber and properly conditioned, it would be rather useless excessive, because you will just have everything jumping around like crazy from thermal coefficients (both PX and FX are 2 magnitudes more stable over temperature than a chemical cell).

author: VNUTDENYER
author_rank: Contributor
timestamp: May 05, 2020, 03:16:22 pm
content: Bob.....Sorry, query started on CalClub thread where PX/FX are know as 7/10v references.TINCells will have most recent month, or so, of warmed/stable data before attempt (oven controlled last 6months). Idea was to compare noise/drift of PX/FX to 3478/1410/1412/Malone 3v/standard cells. Direct PX/FX noise comparison obviously invalid if cells or 3v ref noisier.Would stable 10/7 voltage divider, say 1Mohm total be quieter, possibly? Planned on direct comparison since all data so far, TIS, is not simultaneous so common mode noise can't be removed (or am I just seeing a non problem)? Knowing what PX/FX short term noise should be will validate test setup and further action. Looks like few months before kit gets to me so plenty of time to iron out action plan.

author: VNUTDENYER
author_rank: Contributor
timestamp: May 08, 2020, 04:14:31 pm
content: I probably could have been more clear. Standard cells are in my signature equipment powered and stable last 6 months but E1412A, also in sig, not powered yet so may start with 3478A on mv range. Not worried about readings jumping all over since will not start unless cells at least as stable as PX/FX. Cells can not provide enough current to harm anything and any test setup must allow no drain anyway. Only consideration, I thought, would be technical advisability of adding 2-3 cells to PX to allow direct comparison to FX. If this seems way off base to anyone, please advise. Thanks
HP 5065A A3 and HP5062C A10 modules needed! - Page 1
Forum section: electronics / general

author: 5065AGuru
author_rank: Frequent Contributor
timestamp: May 09, 2020, 03:31:03 am
content: Hi,Doing some experiments and need HP 5065A A3 and/or HP5062C A10 modules.They are the 5 to 60 MHz and 5 to 90 MHz multiplier modules.Anyone have some laying around?Cheers,Corby Dawson

author: jfphp
author_rank: Regular Contributor
timestamp: May 09, 2020, 11:20:05 am
content: I have one 5062-60134 A10 ASSY series 1428 lying in my box of spares for 5061X/5062C.
Solartron 7075 - Page 1
Forum section: electronics / general

author: macaba
author_rank: Regular Contributor
timestamp: April 17, 2020, 08:05:58 am
content: I'm in the process of repairing a Solartron 7075. It has a bright display and all the digital logic seems to work. I've already replaced the mains inlet filter (it smoked after 15 minutes, no surprises there) and now I'm trying to resolve a constant overload condition (the display flashes with 14000 on the relevant integration time).3 of the 4 test modes work, the only one that doesn't (AC test) is the only one that injects a signalbeforethe main input amplifier. The other test modes isolate the input amplifier and inject straight into the integrator.Tested TP17 (Input Amplifier Output) and it's at approx. 23V constantly. Looks like there is a fault at, or somewhere downstream of, IC408.Has anyone got any experience of this? I thought I'd ask because the repair now jumps up a level in awkwardness - IC408 & related components are on the most difficult PCB to get at so I only want to remove it once!

author: cbutlera
author_rank: Regular Contributor
timestamp: April 24, 2020, 01:49:24 pm
content: Quote from: macaba on April 17, 2020, 08:05:58 amJust take it apart, locate the components that you want to probe, then reassemble and probe on the underside of PCB 5.With a bit of practice, it only takes about a minute to partially disconnect and lift aside PCB 6, and a couple of minutes to replace it. I've done this many times, and by the time you have yours fixed, I expect you will have too.To make access easier while you are working on it, you can remove the aluminium shield between the floating and grounded sections.There is a 4-pin rigid interconnect between PCBs 5 and 6 annotated B1-B4 on PCB 6. This can be a little awkward to refit when you first try. I find the easiest method is to first insert the interconnect into PCB 6, not fully home but just enough to hold it in place. Then as PCB 6 is lowered into place, with your tongue at the right angle and illuminated by a strategically positioned torch, it is possible to view the lower tips of the interconnect, to guide it into the socket on PCB 5.
Fluke 87 V, the smallest capacitance and ac voltage values measured . - Page 1
Forum section: electronics / general

author: ifrenide
author_rank: Regular Contributor
timestamp: April 17, 2020, 02:30:05 am
content: Hello everyone, I want to know what is the minimum capacitance ,and ac voltage values can the fluke 87 V measure. I want to bay one for electronic projects,I know it is an industrial multimeter, But if it can measure capacitance values like 4.7pf it will be great, or measure 50uv ac .best regards.

author: ifrenide
author_rank: Regular Contributor
timestamp: April 17, 2020, 02:59:05 am
content: here is the short description, and for sure it is useful but I can not figure out what is the minimum values of capacitance and ac voltage.best regards

author: Fenstergucker
author_rank: Regular Contributor
timestamp: April 17, 2020, 05:50:59 am
content: https://www.eevblog.com/forum/testgear/suggestions-for-a-dmm/msg2752316/#msg2752316Fluke 87V from 2008ceramic condenser set, radial, tolerance +- 10 %Code:value measured10 pF = 0.01 nF (smallest value)22 pF = 0.03 nF33 pF = 0.04 nF47 pF = 0.05 nF56 pF = 0.06 nF68 pF = 0.07 nF100 pF = 0.10/0.11 nF150 pF = 0.15/0.16 nF220 pF = 0.23 nF

author: ifrenide
author_rank: Regular Contributor
timestamp: April 17, 2020, 10:21:31 pm
content: Thank you very very much Fenstergucker
REF01 - different generations - die pictures - Page 1
Forum section: electronics / general

author: Noopy
author_rank: Super Contributor
timestamp: April 10, 2020, 07:23:17 pm
content: Hi all!I hope it´s ok to start a new topic for the REF01. I found no existing topic.Up to now I have decapped four REF01-generations and would like to share them with you.The first generation die was packaged 1976:The second generation was developed 1977:The third generation is missing. Probably it´s only one year in which it could have been produced. "My" generation 2 package dates back to 1986 and generation 4 was designed 1987. But there must be a generation 3 because the designs have names with a revision coding: 1800Z, 1800Y, 1800W => The X is missing. Perhaps generation 3 was buggy.The fourth generation was developed 1987:There is a die picture in a datasheet that probably shows the generation X. With an overlay you can spot the small changes:The fifth generation is actually a ADR01 as the REF01 moved to Analog:Sorry, bad picture...From 1 to 2 PMI did only small geometry changes at the output and at one double transistor.From 2 to 3 there were added more resistors and fusable links to adjust the Output voltage and the temperature drift. The startup circuit was changed. The die got bigger. Two spare transistors were added, perhaps for the startup circuit. (Actually I have no generation 3 but with the picture out of the datasheet it seems it got all the changes you can see in generation 4.)From 3 to 4 the spare transistors were covered by the output metal layer.From 4 to 5 Analog wanted to earn more money and canceled the REF01 by putting ADR01 in the packages.Overview over all:https://www.richis-lab.de/REF00.htmGreetings,Richard
SR620 TI setup procedure? - Page 1
Forum section: electronics / general

author: notfaded1
author_rank: Frequent Contributor
timestamp: April 05, 2020, 06:57:09 pm
content: Minus the data in the manual I've seen a few extra docs floating around but am not sure where to find them now? Setup procedures for the SR620 for getting best time interval readings. How do you configure yours? In frequency I know the SR620 may actually be worse than HP53132A but for time interval it's one of the kings. This is my Thunderbolt 10MHz feeding into SR620 on Frequency.I've wanted one of these for while and finally got a nice one with option 1.Bill

author: notfaded1
author_rank: Frequent Contributor
timestamp: April 05, 2020, 07:32:59 pm
content: That was cold I'm trying it again after warming up for a while... I found this guide from NASA. I need to feed it external reference next.

author: notfaded1
author_rank: Frequent Contributor
timestamp: April 05, 2020, 07:49:55 pm
content: Looks much better after warming up some.

author: Theboel
author_rank: Frequent Contributor
timestamp: April 05, 2020, 08:54:03 pm
content: Hi notfaded1,look at PRS10 manualhttps://www.thinksrs.com/downloads/pdfs/manuals/PRS10m.pdfYou can find how to set SR620 for "coarse and fine" measurementAnton

author: notfaded1
author_rank: Frequent Contributor
timestamp: April 05, 2020, 09:07:34 pm
content: Quote from: Theboel on April 05, 2020, 08:54:03 pmThanks this reminded me where I saw some of this before! I'm waiting for a new 24V 3A power supply that should come tomorrow for a recently acquired a PRS10. I have a Ublox LEA-6T on a pcb that can discipline the PRS10 that I was hoping might become my new house standard. Thanks for the tip!Bill

author: Theboel
author_rank: Frequent Contributor
timestamp: April 06, 2020, 01:27:01 am
content: Thanks this reminded me where I saw some of this before! I'm waiting for a new 24V 3A power supply that should come tomorrow for a recently acquired a PRS10. I have a Ublox LEA-6T on a pcb that can discipline the PRS10 that I was hoping might become my new house standard. Thanks for the tip!Hi Bill,I love to hear about PRS10 discipline with ublox 6T and TDEV and MDEV chart will great.May I Suggest You to use a the best cable for made measurement. same length same type same connector brand and made at least 3 time measurement and the last one stay away from off line UPSAnton
oops - Page 1
Forum section: electronics / general

author: 5065AGuru
author_rank: Frequent Contributor
timestamp: March 31, 2020, 01:52:36 am
content: could not delete this post!

author: guenthert
author_rank: Frequent Contributor
timestamp: April 01, 2020, 06:02:43 pm
content: Might as well give it some meaning by telling us, what we're looking at?
Trimble 57963-D GPSDO status - Page 1
Forum section: electronics / general

author: james_s
author_rank: Super Contributor
timestamp: March 30, 2020, 05:33:13 am
content: I have one of these GPSDO modules that I've been playing with and I'm at the point where I'm working on getting things buttoned up in a housing. I'm trying to work out connections for some status LEDs that I can put on the front panel, the pinout chart that came with it lists a few pins that mention lock, unlock and holdover however from experimenting they do not seem to behave as expected. They change states when the unit initially locks but I haven't found one yet that does anything during holdover or alarms. It seems some remove the existing status LEDs from the board however if at all possible I'd really like to get the status from the 50 pin connector. Lock, holdover and alarm would be ideal, I thought about using a microcontroller monitoring the serial output although I want to keep the ability to plug in a cable and fire up Lady Heather. Surely somebody has been through all this already?
Adapter for converting PLCC44 to DIP-48 - Page 1
Forum section: electronics / general

author: notfaded1
author_rank: Frequent Contributor
timestamp: March 22, 2020, 08:39:03 pm
content: I'm curious if using an adapter like this:https://megadepot.com/product/ee-tools-pa44-48u-44-pin-plcc-socket-adapter?format=v&p=ms&source=ads&gclid=CjwKCAjwsMzzBRACEiwAx4lLG9GdmM-wfAdkWl2bwqZofyDjE8fKRei6W9miFWmMmzp4BZmLOFIkIxoCPlUQAvD_BwECould be used to put this in to replace a DIP-48 version of the chip?https://www.datasheets360.com/pdf/-984516674197613276This is the main chip in the Datum 4040A Cesium Frequency Standard that sometimes fails. The DIP-48 are harder to find but the PLCC are available. Does an adapter like this work in a situation like this possibly?Regards,Bill

author: notfaded1
author_rank: Frequent Contributor
timestamp: March 22, 2020, 08:52:35 pm
content: None are cheap I found another one here:https://www.jdr.com/PA44_48U_p/pa44-48u.htmJust curious if anyone has ever tried something like this before?

author: notfaded1
author_rank: Frequent Contributor
timestamp: March 22, 2020, 09:21:39 pm
content: It may not matter now... I think I found some DIP-48 STEL-1173. I'll know tomorrow I hope.

author: edpalmer42
author_rank: Super Contributor
timestamp: March 22, 2020, 09:30:33 pm
content: First question is why do you think the STEL-1173 is dead?Second question is where did you look for replacement chips?Third question is have you tested the tube to make sure it's alive? There's no point replacing the STEL-1173 if the tube is dead.Back in 2014 when I was trying to fix my FTS-4065A, I was looking for the same chip. Mine was the PLC44 version and it was easier to find the DIP version. I looked at a PLCC -> DIP adapter, but the spacing was very tight and I really didn't want to use an adapter. I eventually took a chance and bought the PLCC chip from Aliexpress. It worked out fine. The chips were genuine and everything was good. The link doesn't work anymore, but using google shows more hits than searching Aliexpress directly.Don't forget to buy two or three in case you get a dead one. You might also want to solder in a socket so future replacements are trivial.Good luck!Ed

author: edpalmer42
author_rank: Super Contributor
timestamp: March 23, 2020, 01:04:40 am
content: Another point just occurred to me. The adapters you're looking at are designed for a specific purpose - programming chips. It's unlikely that the pinout will match what you need. You'll likely need to build your own adapter by combining a DIP 'plug' and a PLCC socket on a custom PCB.Ed

author: MegaVolt
author_rank: Frequent Contributor
timestamp: March 23, 2020, 12:17:49 pm
content: Aliexpress offers cheap options but only for DIP 40.And as correctly said above, there is no guarantee that the pinout will be preserved. You may need to add many wires to this adapter.https://aliexpress.ru/item/32818310169.html

author: testpoint1
author_rank: Frequent Contributor
timestamp: March 28, 2020, 11:31:25 pm
content: you may modify many pins, since the adapter is for Flash Eprom etc.
Bought a 3458A but... - Page 1
Forum section: electronics / general

author: wolfy007
author_rank: Frequent Contributor
timestamp: March 27, 2020, 05:37:37 am
content: Bought a second 3458a recently, claimed working. Talked to the seller and seemed genuine and helpful. He dropped it of to my sisters house, she lived near by, and I picked it up.Problem is I got it home and it wouldnt power on. So recently I opened it up to take a look and repair it, mostly looks clean, checking A6 board for issues but then...On the A5 board, under the GPIB port, I found spew from a ruptured IEC EMI filter. The filter had been replaced, but the ass that must have replaced it didnt clean up the mess and as it appears to be a rather stubborn mess to remove happened many years ago. The previous owner never opened it so wasnt aware of this but never had problems with it.I have tried cleaning it with isopropyl but its barely coming off. Its coming off the frame (& its caused a bit of corrosion) but any ideas on a safe way to remove this spew-now-glue from the A5 board (picture below)?PS: A5 board is revB and A6 board is RevA (and has a couple bad caps), latest date code suggests manufactured after april 1994

author: MiDi
author_rank: Frequent Contributor
timestamp: March 27, 2020, 08:08:24 am
content: What a mess and it is all over the place!I would try to scrub carefully with sharp plastic e.g. spudger, plectrum or hard wood with sharp edge.For cleaning the residues you could try a good pcb cleaner - in my experience they clean better than pure ipa.Simple soap could be worth a try too.If you do not already know, TiN has great articles on repairing on xDevs.com and here too.For recapping my3458A Worklog with a detailed overview of the parts that were replacedmay be useful.

author: vonB
author_rank: Newbie
timestamp: March 27, 2020, 08:15:59 am
content: I was using couple of times somethink like "fireplace window cleaner" with good results

author: Kleinstein
author_rank: Super Contributor
timestamp: March 27, 2020, 08:35:21 am
content: The good thing is that this is only the digital / input power supply. So this part of the circuit is not sensitive to leakage. If at all it would be SRAMs that may need a little more current, but these are already a little away from the real mess.

author: MadTux
author_rank: Frequent Contributor
timestamp: March 27, 2020, 11:10:52 am
content: That's only stinking tar puked out of the Schaffner-Paffner filter.Soak it in hexane or some other nonpolar solvent.Gasoline for 2 stroke chainsaws without benzene and other stinky aromatic hydrocarbons should work great, too.

author: wolfy007
author_rank: Frequent Contributor
timestamp: March 28, 2020, 03:07:23 am
content: Thanks everyone, will give it a go. Normaly I repair scopes, signal generators, power supplies even the odd voltage reference and such, but this is more sensitive, more intricate and expensive so taking my time and hopefully learn something new in the process. May ask a few more questions before this one is done.
Put my Fluke 8505A and a broken 845AB on eBay - Page 1
Forum section: electronics / general

author: mvanocht
author_rank: Contributor
timestamp: March 27, 2020, 03:01:28 am
content: Hi guys, with Hamvention cancelled I decided to list a few of my items on eBay. The 8505A is really stable and great on DCV. It is one of only a few meters that reads full-scale of 1,999,999 instead of 1,100,000. It will do 7 1/2 digits but only on the 10 VDC range. There is also a Fluke 845AB that needs repair and a Yokogawa 7651 DC Source (parts unit), and a couple of RF Signal Generators.https://www.ebay.com/sch/vincent_electronics/m.html?

author: TiN
author_rank: Super Contributor
timestamp: March 27, 2020, 04:01:08 am
content: Wrong section, suggest you move it to buy/sell.
Sinclair DM350 calibration - Page 1
Forum section: electronics / general

author: zerto
author_rank: Contributor
timestamp: December 25, 2019, 02:55:38 pm
content: Hello,I have extracted my first multimeter from the attic and it is still working (I bought it in the early eighties !). A quick check on voltage measurement shows a 5% error over 2.5, 5, 7.5 and 10 V reference voltage. I would like to try to calibrate it so I am looking for the Sinclair (Thurlby Thandar Instruments) DM 350 digital multimeter service manual, anyone who could share it with me ? that would be fantastic !I found a web site with the manual but it is rather complicated to download it... even the registration to the web site is quite complicated, I am not sure what they are asking for.Regards

author: zerto
author_rank: Contributor
timestamp: December 25, 2019, 03:04:12 pm
content: adding some images...

author: Andreas
author_rank: Super Contributor
timestamp: December 25, 2019, 09:52:35 pm
content: Hello,at that time only few chips were used for DMMs. (ICL71xx)I would look at the 28 pin Chip number and a data sheet for it.Then adjust the reference voltage to the value of the data sheet (100.0 mV or 1000 mV)This will help at least for the DC-voltages/currents.But before I would clean/reseat the contacts of the chips in the socket.with best regardsAndreas

author: zerto
author_rank: Contributor
timestamp: December 26, 2019, 06:09:17 pm
content: Thanks for the tips, the chip is a MP7138A, but I could not find the datasheet yet.I will cleanup the contacts as you are suggesting and check the reference voltage if I can get the service manual.Best Regards

author: iMo
author_rank: Super Contributor
timestamp: December 26, 2019, 06:30:59 pm
content: A brief info on the chip:https://www.americanradiohistory.com/hd2/IDX-Consumer/Archive-Poptronics-IDX/IDX/70s/78/Poptronics-1978-03-OCR-Page-0070.pdfhttps://www.americanradiohistory.com/hd2/IDX-Consumer/Archive-Poptronics-IDX/IDX/70s/78/Poptronics-1978-03-OCR-Page-0071.pdf

author: zerto
author_rank: Contributor
timestamp: March 21, 2020, 02:45:15 pm
content: I wanted to share the great outcome of this topic:After cleaning the main chip, the switches and the rest of the board using a contact cleaning spray, and with the help of the service manual I have been able to recalibrate the unit at better than 0.1% error on DC voltage ! I am really happy to be able to reuse my first multimeter, being confident on its accuracythank you all for the tips
Nice 5061A on Eeebay - Page 1
Forum section: electronics / general

author: 5065AGuru
author_rank: Frequent Contributor
timestamp: March 13, 2020, 02:07:59 am
content: https://www.ebay.com/itm/HP-Agilent-5061A-Cesium-Frequency-Standard-w-Opt-01-C13-Good-Working-Unit/233521981160?hash=item365efea6e8:g:HeAAAOSwY2peZ~fBFrom one of the time nuts.This one looks pretty good.It has the 10811A oscillator retrofit and the desirable late model STD "mini" tube. (smaller diameter)Usually a lot better chance of a useable tube it its the standard mini!Cheers,Corby

author: Theboel
author_rank: Frequent Contributor
timestamp: March 13, 2020, 01:54:49 pm
content: Quote from: 5065AGuru on March 13, 2020, 02:07:59 amMay I ask why ?

author: 5065AGuru
author_rank: Frequent Contributor
timestamp: March 15, 2020, 12:50:37 am
content: The "mini" tubes for the 5061A/B were the last ones HP manufactured so you have a better chance they have some life versus the older larger diameter tubes.The standard tubes (versuss the option 004) have a longer operating lifetime, so a standard "mini" is the best of both worlds!Cheers,Corby
5061B x 2 in evilbay - Page 1
Forum section: electronics / general

author: syau
author_rank: Frequent Contributor
timestamp: February 10, 2020, 05:50:26 am
content: While still working on my 5065A restoration found there are two 5061B in evilbayOne come with high performance tube.www.ebay.com/ulk/itm/274258439642www.ebay.com/ulk/itm/283777399268

author: edpalmer42
author_rank: Super Contributor
timestamp: February 10, 2020, 06:26:03 pm
content: Actually four recent vintage 5061B, one Datum 4040A, and one Datum Rb standard - all working! Quite a nice payday for him!

author: notfaded1
author_rank: Frequent Contributor
timestamp: February 10, 2020, 06:26:58 pm
content: If someone wants to pay that much! The datum rubidium standard the 8040 is even older than the one I got recently but one nice thing is it has multiple outputs on the back... I can't quite read the value in the picture though.1 and 4 looks like 10MHz but 2 and 3 are something shorter... maybe 5 and 1? Also the lock light isn't on.The 4040A looks idk now... the lock light is on but half the connectors are missing and there's stuff taken apart so what does that mean? It's very similar to my unit but has the switch for storage and normal. Looks like someone wrote 10 next to the one output left on the back. It's a gamble but could be something maybe.Tempting to be honest but I just bought an HP3458A this weekend so maybe I shouldn't risk itBill

author: edpalmer42
author_rank: Super Contributor
timestamp: February 10, 2020, 07:32:10 pm
content: Quote from: notfaded1 on February 10, 2020, 06:26:58 pmWhat? I think you've got your wires crossed. The guy selling the 5061B units is selling a Datum PRFS-202 Rb standard with the lock light on, not an 8040.QuoteI see what you mean. I'm guessing that's why the price is so much lower. My first thought was that someone had salvaged the hole plugs that were used when options weren't equipped. Not an issue. I did wonder about those missing screws.Ed

author: syau
author_rank: Frequent Contributor
timestamp: March 11, 2020, 03:32:02 am
content: Looks like this one from one of our fellow time-nutwww.ebay.com/ulk/itm/233521981160

author: testpoint1
author_rank: Frequent Contributor
timestamp: March 14, 2020, 03:55:54 am
content: you can play the 5071A now,https://www.ebay.com/itm/184209935273
ESI SR104 standard resistance on Ebay - Page 1
Forum section: electronics / general

author: splin
author_rank: Frequent Contributor
timestamp: March 07, 2020, 02:03:27 am
content: The bidding looks like a master-class in how *not* to bid on Ebay - unless one of them is the sellor or an associate!

author: MiDi
author_rank: Frequent Contributor
timestamp: March 07, 2020, 11:39:30 am
content: Have it several days on my watchlist, but only for reference - way out of my budgetAsking me what price is new and what is usual price for used one?

author: splin
author_rank: Frequent Contributor
timestamp: March 07, 2020, 01:17:13 pm
content: Quote from: MiDi on March 07, 2020, 11:39:30 amNew, around $8,500Used? They used to go for around $2000 or so; they seem to come up for sale so rarely now that who knows?The price for this particular example has been driven up by a bidding war between two people but that might not happen to the next one. It will likely set expectations for the sale price of subsequent models.

author: Kosmic
author_rank: Super Contributor
timestamp: March 07, 2020, 01:34:18 pm
content: Yeah, kind of suspect when you see a user with 0 feedback driving the price up.

author: WattsThat
author_rank: Frequent Contributor
timestamp: March 07, 2020, 03:30:14 pm
content: Zero feedback bidders:1) shill2) idiot3) fool with deep pocketsPick one.

author: Villain
author_rank: Regular Contributor
timestamp: March 08, 2020, 06:53:23 pm
content: went for 3.3k$

author: Macbeth
author_rank: Super Contributor
timestamp: March 09, 2020, 01:01:15 am
content: I have to admit the Chinese fakers are missing out on this one (or are they?). I mean it's just a relatively large box with a 10k resistor inside and some nice binding posts - as soon as you open it to see the magic you have destroyed it anyway if it was real.I could knock one of these up for £50, ok if I actually chucked in a proper Vishay S102C maybe £75.Love to see paypal enforce a claim after 3 years of data proving it was wrong.

author: notfaded1
author_rank: Frequent Contributor
timestamp: March 09, 2020, 01:44:04 am
content: I would like one of these to go with calibrating 8.5 digit MM's but I'm not sure for hobbyist's that 3k+ dollars makes a ton of sense.B

author: TiN
author_rank: Super Contributor
timestamp: March 09, 2020, 03:46:38 am
content: Using SR104 for DMM calibration is somewhat a waste of great resistance standard.

author: notfaded1
author_rank: Frequent Contributor
timestamp: March 09, 2020, 11:34:47 am
content: That's easy for you to say... You've got one! Of course it would be standard for everything else. I still think the one you fixed with the oven is in some ways neater anyhow... I doubt anymore of those will show up on the market though. It was hardly even a product... has anyone ever seen another one?