hybridfree/eevblog-posts huggingface dataset:
Hameg HM8131-2 DDS Function Generator - Service Manual / Calibration Procedure? - Page 1
Forum section: electronics / testgear

author: richipedia
author_rank: Contributor
timestamp: January 05, 2022, 08:48:27 pm
content: Hi everybody,I recently got hold of a Hameg HM8131-2 DDS function generator.Apart from a hypersensitive encoder and a little DC offset, it seems to be working fine.Any idea on how to obtain a service manual for this thing? I already checked the obvious resources (Rohde-Schwarz website, elektrotanya, ko4bb, this forum, general Google search) but found nothing except the user manual, which does not include schematics or a calibration procedure.Is there somebody here with experience with the device, who can tell me what the individual trimpots and jumpers are good for? I would really like to work based on some guidance before I screwdriver the function generator :-(

author: shakalnokturn
author_rank: Super Contributor
timestamp: January 06, 2022, 09:16:41 pm
content: Hello,I've read several reports here about how helpful Rohde-Schwarz have been in providing service information for their Hameg equipment, try sending them an email.

author: 9aplus
author_rank: Regular Contributor
timestamp: November 13, 2023, 07:31:50 pm
content: Any luck with calibration and service manual?Just purchased one on auctionhave no clue working condition or not....

author: richipedia
author_rank: Contributor
timestamp: November 14, 2023, 07:50:50 am
content: Yes - you can find it on elektrotanya.com.

author: 9aplus
author_rank: Regular Contributor
timestamp: November 14, 2023, 09:41:30 am
content: You mean this one?https://elektrotanya.com/hameg_hm8131-2_functiongenerator_um.pdf/download.htmlIt seems to be only User manual....The search there showing only that one, am I missing something?

author: richipedia
author_rank: Contributor
timestamp: November 15, 2023, 07:15:02 am
content: My bad, I thought it would be available by now.However, now it is:https://elektrotanya.com/hameg_hm8131-2_service_manual.pdf/download.html
Rigol DS2000 Protocol Decoder turns off above 100ms/div After firmware update - Page 1
Forum section: electronics / testgear

author: MotoDan
author_rank: Contributor
timestamp: November 15, 2023, 06:19:39 am
content: I just updated my DS2000 scope firmware to the latest version and now none of my Protocol Decoders (specifically RS232) will not work when I set the horizontal sweep above 100ms/div. My initial thought was that Rigol made a change since my last update, but I don't see anything in the release notes. I went ahead and rolled back the firmware version, but still no joy. My next thought was that some parameter got changed (like many do) during the update, but I can't find anything that fixes the issue. Just prior to the update I have been working with a very slow sweep of 1 sec/div and the decoder was working just fine. In fact, I can't recall ever having the scope automatically turning of the decoder (Bus Status).Has anyone ever experienced this with their DS2000 series scope? Could you verify if your scope turns off the Decode for sweep times over 100ms/div?Thanks!
Siglent SDS2000X, SCPI, Averaging - Page 1
Forum section: electronics / testgear

author: colorado.rob
author_rank: Frequent Contributor
timestamp: November 15, 2023, 03:21:54 am
content: I'm writing an automation script for creating a Bode plot using the SDS2000X (non plus) and an SDG2000X.To get the best dynamic range, I need to use averaging (ACQW AVERAGE,4) and increase this averaging level for every 10dB in attenuation.However, I cannot for the life of me tell when the scope has captured all of the frames needed to meet the averaging I have specified. The trigger fires as soon as the first frame is captured. I currently wait a computed amount of time before capturing the measurements. But that's slow, inexact, and error prone.What's the proper way to determine via SCPI that all of the frames specified for averaging are captured?
Electronic load with low shunt capacitance - Page 1
Forum section: electronics / testgear

author: KlausKragelund
author_rank: Regular Contributor
timestamp: July 16, 2022, 01:46:44 pm
content: HiI have a Tenma 72-13210 and a Kunkin KP184 electronic loadI do a fair amount of gain/phase measurements of power supplies, and I would like a load that does not add capacitance to the outputThe Tenma adds 4.5uF and the Kunkin 2uF, so they will affect the loop (I spew noise back)Normally the output is steady voltage wise, so I do not need fast response, more like a feedforward type, like an old style pass transistor load, with none or very little feedbackVoltage is from 1V to 60V, load 1mA to 10ADoes such a ready made instrument exist?RegardsKlaus

author: Gediminas
author_rank: Regular Contributor
timestamp: November 14, 2023, 09:24:36 pm
content: I am probably late with the answer (also got Tenma, yes, it has 4.5uF across the input), but what if you will desolder the input capacitor?The side effect could be that the load will start to oscillate in come cases or become unstable, but if in your case it will not do that, then I guess you could use it.
Programmable resistive load - Page 1
Forum section: electronics / testgear

author: Nogtail
author_rank: Regular Contributor
timestamp: November 17, 2023, 01:50:53 am
content: I've got a PWM LED driver I'd like to test across a large range of voltages, frequencies and loads. The PWM rate can be relatively high (over 100 kHz) which doesn't seem to play nicely with most DC loads.So far I've been manually switching in a bank of power resistors. Unfortunately the ones I have are wire wound and more inductive than I'd like. I'd also like something I can automate to test at a variety of loads.Does anyone know of some equipment that can handle 10-20 W at around 100 kHz? Something purely resistive is ideal, but a DC load that can handle a 100 kHz square wave would also do the trick. Bonus points if it's not ridiculously expensive!Thanks!

author: slugrustle
author_rank: Frequent Contributor
timestamp: November 17, 2023, 02:34:08 am
content: I was going to cheekily suggest a rheostat, but you've already tried (assuming wirewound) power resistors and they were too inductive. A rheostat wouldn't fix that.If spiffy equipment is not available, there are non-inductive power resistors available. They typically come in a package that needs to be mounted to a heatsink. I recently bought some resistors like this for a test at work; they were effectively TO-220 case parts and rated to 30W. The nice thing about these kinds of resistors is they tend to have isolated packages, often ceramic backed.Here's an example of a 100W 100Ω resistor in TO-247. Datasheet says 11.7nH inductance.https://www.digikey.com/en/products/detail/riedon/PF2472-100RF1/2447861https://riedon.com/resistors/view/to-247-power-film-resistors-pf2470Worth saying twice that you'll need a heatsink.EDIT: The trouble with E-Loads is they pretend to be resistors (CR mode) by modulating the gate inputs to a bank of power MOSFETs with a control loop. It would have to be a screaming fast control loop to make a power MOSFET look like a programmable resistance to a 100kHz square wave. You might be able to set up a "dumb" essentially open loop current sink with a large power BJT, an emitter resistor, and a voltage source to set the base-to-ground voltage. I know it's not a resistor, but it is a programmable open loop current sink.EDIT2: Resistance wire of a suitable diameter bent into a non-inductive shape (squiggle line) that minimizes path length. Mount it on a high temperature substrate and tap into the wire at various points with a clip that can handle the current.

author: Nogtail
author_rank: Regular Contributor
timestamp: November 17, 2023, 11:11:52 am
content: My backup plan was to get a few of the thick film resistors, wire them in series and short them out with some chunky relays to vary the load. I was hoping there was some existing equipment that does what I wanted but I haven't come across anything yet. Thankfully I've got a giant heatsink I salvaged from an old solar inverter that should be perfect for keeping them cool.
Siglent 1000x vs 1015x Firmware question (and issue??) - Page 1
Forum section: electronics / testgear

author: kn4ycd
author_rank: Newbie
timestamp: November 14, 2023, 07:50:40 pm
content: Just got my SVA-1015x and I have a question! The system info page shows 3.2.2.6.0R1 as the installed firmware, yet looking on the Siglentna.com firmware downloads, I see 3.2.2.4.0R2 as the latest specifically mentioned for the 1015X.Has siglent merged firmwares together? It seems out of whack that I have firmware not listed on their website. I bought my device direct from siglentna.com.Thanks!Jim

author: tautech
author_rank: Super Contributor
timestamp: November 14, 2023, 08:01:11 pm
content: Quote from: kn4ycd on November 14, 2023, 07:50:40 pmFor some time there have been moves to move away from model specific firmware so to have one version for a complete range.Latest SVA1000X firmware is here:https://int.siglent.com/download/firmwares/?ProId=30

author: kn4ycd
author_rank: Newbie
timestamp: November 14, 2023, 08:09:56 pm
content: Thanks! That's what it seemed like, but before I pulled the trigger, I was hoping to get verification.
Anritsu Scorpion MS462X ALC calib power meter options - Page 1
Forum section: electronics / testgear

author: alan.bain
author_rank: Regular Contributor
timestamp: October 22, 2023, 10:40:33 pm
content: The manual for the MS462XX stipulates an Anritsu power meter (ML2430A) which itself can emulate HP436A/437B/438A for the ALC procedure which is performed under GPIB control.I've got a suitable HP power sensor and cable, but always used a meter without GPIB. HP437Bs were once practically given away (without power sensors) but now seem hard to find. I'm trying to work out if a 436A or 438A could be used instead as they seem marginally more findable on the second hand market. Does anyone know if any of these can be used to perform the calibration? Mine got lost due to BBRAM failure.The 436A is old style state-machine single character GPIB commands. The 437B and 438A are more similar - although not identical (best comparison I know of is in the Gigatronix 8650 manual e.g.https://manuals.repeater-builder.com/te-files/GIG/GIG%208650%20Series%20Operation.pdf

author: DaJMasta
author_rank: Super Contributor
timestamp: October 23, 2023, 05:01:11 am
content: Almost every newer meter speaks the old GPIB commands through an option setting, when I had to do this with a similar VNA, I used an 8541C, but if you've already got the sensor - I would have thought the later HP meters would still fit the bill.In any case, there's some discussion of the individual protocols here:https://www.manualsdir.com/manuals/44433/anritsu-ml2430a.html?page=182maybe that can shed some light on how cross compatible they are.

author: alan.bain
author_rank: Regular Contributor
timestamp: November 14, 2023, 06:31:29 pm
content: So to leave here in case anyone else finds useful I tried an HP438A. The VNA talked to this fine, but it was a bit unclear what calibration factor to use. The value set was that for the 50MHz calibration source (using an 8481A sensor). The calibration seemed to use this single value over the whole frequency range and clearly at 3GHz the sensor cal factor is not the same as at 50MHz. I was expecting either to be able to enter a table, or to be prompted to change it at various points, but this didn't seem to be an option. It seemed to assume that the power meter did some automatic table lookup, but I've not used a power meter modern enough to have such a feature.Alan
Broken 121GW input terminals - Page 1
Forum section: electronics / testgear

author: hainjedaf
author_rank: Contributor
timestamp: September 08, 2023, 03:24:18 pm
content: Hi,I use my EEVBlog 121 GW multimeter regularly with both probes and banana plug leads in test setups.Now have, because of the use of banana plugs, the insides of the terminals broken off.There are plastic bushings around the terminals. These both insulate and keep the terminals close fitting to the banana jack.These bushings have all either split or completely fallen out.The terminals alltogether form one plastic block with 8 soldering leads.I tried Brymen if I could buy a replacement to repair my meter but to no avail.Does anyone know where to get parts for the EEVblog 121 GW?All I need is the terminal block.(a broken meter where I can harvest the part would suffice too).Kind regards,Marout Sluijter-BormsAmsterdam NL

author: Veteran68
author_rank: Frequent Contributor
timestamp: September 08, 2023, 04:07:38 pm
content: Quote from: hainjedaf on September 08, 2023, 03:24:18 pmThe 121GW is not made by Brymen, it's made by UEI. It was a custom design by/for Dave and I don't believe UEI directly services/supports users. I'm not sure Dave stocks or supplies parts but you might try contacting him directly, maybe he has a dead meter he'd send you for parts.

author: J-R
author_rank: Super Contributor
timestamp: September 08, 2023, 04:43:46 pm
content: The info you need is here:https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg2792850/#msg2792850

author: hainjedaf
author_rank: Contributor
timestamp: September 08, 2023, 06:00:59 pm
content: Quote from: J-R on September 08, 2023, 04:43:46 pmThanks a milion for the link. I already posted a reply there.This issue hopefully will resolve itself there.

author: hainjedaf
author_rank: Contributor
timestamp: November 14, 2023, 02:01:16 pm
content: Got my new terminals today!Thanks Dave! Brilliant.Tomorrow I'll set myself down to fix the 121gw.
Lecroy DDA-125  (LC684?) Combining 4 Channels - Page 1
Forum section: electronics / testgear

author: dave_n_s
author_rank: Contributor
timestamp: May 21, 2023, 12:11:53 am
content: Some education please.I've just acquired a couple of, in most respects, DDA-125s to use as 4 channel scopes.The manual says that to select all four ADCs to support one 8 GS/s channel, select 1 or preferably Automatic, noting that I need the PP096 input adapter as well.One unit displays options for 1, 2, 4 & automatic selection of the correct number of channels in the block on the horizontal set-up menuThe other just displays 2 & 4 in the same block on the set up menu.Neither had the PP096 adapter fitted.Is anything (hardware or software mod) required to be able to create a single 8 GS/s channel? Am I missing another selection?On the one that doesn't do what I expected, combining pairs of channels works as it should.Thanks!

author: dave_n_s
author_rank: Contributor
timestamp: May 26, 2023, 04:24:49 pm
content: To add to this, we have a couple of DDA-120's which are to a large degree CRT versions of the DDA-125, covered by the same manual. Both of those behave as expected - they offer 1,2, 4, Auto channel options with nothing connected to the inputs, not even an adapter.Usual prompt responses from Teledyne Lecroy tech support, but the responder wasn't familiar with this generation of scope.Does that ping any memories of what might be going on?Thanks

author: shakalnokturn
author_rank: Super Contributor
timestamp: May 28, 2023, 09:41:46 am
content: From what I remember of my LeCroy's:In timebase menu the DDA-120 would have settings for 1, 2, 4 channel usage and allow to combine to 1 without external adapter, the 9384 will allow 2, 4 channels usage in the menu but external combiner must be connected between channels 2&3 to allow single channel use.When combining is enabled the channel reallocation should be shown on LHS of the screen as you go above the default 4 channel maximum sample rate.

author: KK6IL
author_rank: Regular Contributor
timestamp: November 13, 2023, 11:41:33 pm
content: The PP096 input adapter is an external device that apparently connects all 4 inputs to a single BNC connector. There are several listed for sale on Ebay starting at $75
I wish all test lead probes had threads for accessories like Probe Master! - Page 1
Forum section: electronics / testgear

author: TomKatt
author_rank: Frequent Contributor
timestamp: November 14, 2023, 06:32:51 pm
content: Just got myself a set ofProbe Master 8000series "softie" test leads. As nice as the probes are themselves, what I really love are thelarge assortmentofaccessoriesavailable - especially the screw-on alligator clips and spring hooks. I use alligator clips and hooks all the time for no-handed measurements, and the ones that friction fit on the probe tip inevitably get loose and they fall off with the lightest movement. The screw-on clips and hooks are nice and solid, and every Probe Master part has a nice quality fit & finish. I'm a bit surprised this style of threaded probe tip is not more common. I was hoping that these accessories would also fit Dave's BM235 leads, but it looks like those threads are smaller 2mm while the Probe Master threads are 4mm... The Brymen screw-on banana adapters seem to disappear when you take your eyes off them - the idea is nice, but they got misplaced too easily.While not threaded, their scope probes also have a very large assortment of accessories available. So in addition to getting high quality made in the US leads, the shear number of options is almost worth the price of admission.

author: ebastler
author_rank: Super Contributor
timestamp: November 14, 2023, 06:57:17 pm
content: Quote from: TomKatt on November 14, 2023, 06:32:51 pmThe ProbeMaster threads are #8-32 UNC, apparently -- not for users on this side of the pond...The probes that came with my Brymen 257s have M2.5 threads.

author: TomKatt
author_rank: Frequent Contributor
timestamp: November 14, 2023, 07:04:47 pm
content: That's too bad. But I am surprised that this design has not become more universally popular - it really works quite well.

author: ebastler
author_rank: Super Contributor
timestamp: November 14, 2023, 07:12:51 pm
content: A pity they didn't agree on one thread size. But ProbeMaster might have been first, and maybe Brymen (or whoever makes their probes) preferred a metric thread?I do agree that the Brymen banana adapters areveryeasy to lose. I still have both of mine, after several years of use -- but only after I retrieved one of them from a corner on the floor of a friend's lab, when I visited him again weeks later...
USB Meter  KWS-V30 : It seems broken but it just needs a calibration - Page 1
Forum section: electronics / testgear

author: Filippo52
author_rank: Regular Contributor
timestamp: November 13, 2023, 03:55:27 pm
content: I purchased this cheap meter on Aliexpress to take quick measurements while charging cell phones.As soon as it was opened, the reported voltage and current values were incorrect by an unacceptable percentage equal to 7-8% for the voltage and also by 10-15% for the current. All faulty errors.I tried to do a few maneuvers and suddenly I found myself first with even more incorrect values: errors of up to 50% less and then finally with all zeros.This is really a big problem for this tester as the button, indicated with a red arrow in the first photo, is in a position where a "finger" can occur while inserting the tester and therefore carrying out a calibration or a reset in a completely unconscious way. I have read reviews of this tester where it was declared faulty which suggest this problem.I thought of a faulty example, but then continuing to tinker I realized that the function button intended to change some readings in reality, if pressed while inserting the tester into the USB port, caused either a "reset" or a "calibration" of the meter.With a little patience I managed to find how to calibrate the voltage:just finish a reading by extracting the tester with the button pressed to read the watts and reinserting the tester, still with the button pressed. At start the tester will indicate the voltage value equal to 5.00 volts and from that point it will follow the variations in applied voltages.Simply insert the tester in this mode into a USB port that is supplying an "exact" voltage of 5 volts and once the button is released we will have our device perfectly calibrated.Unfortunately I was unable to find the similar procedure for calibrating the current that I believe should exist. I couldn't even find the instructions for this model. Other models from the same manufacturer have a very easy but still very different on-screen wizard.Now I have the tester which is quite precise on voltage but which gives current values as low as 10%.Opening the object I identified the shunt resistor (R005) for reading the current; but intervening on it, having to increase it to increase the reading of the measured current, is, as you imagine, very difficult.I ask you if any of you have had more luck than me and using this object managed to find the procedure to calibrate the current measurementThanks in advance​Filippo
teledyne T2C trigger cable pinout - AC032XXA-X - Page 1
Forum section: electronics / testgear

author: metebalci
author_rank: Frequent Contributor
timestamp: November 13, 2023, 05:52:04 am
content: T2C has 9 pin DIN connector for trigger in/out. The cable is pretty difficult to find, anyone knows the pinout or is there an easy to find alternative ? I see on an NI page pin 1 is used for GND, and pins 6 and 9 are used for triggering, maybe it is the same ?
R&S: Service manuals for the ESU2, EZK and EZP. - Page 1
Forum section: electronics / testgear

author: Richard9026
author_rank: Newbie
timestamp: December 06, 2018, 06:56:37 pm
content: Hello there!I recently got hold of some R&S test equipment. The equipment isn't in good working condition, so it needs some repairs. For proper repairs, I need the service manuals for these devices.They are from the '70s. I attached an image of the test equipment. It consists of a rack-holder called MSU, that holds the EZK, EZP and the test receiver ESU2.Yes, I already contacted the R&S company itself. I obtained datasheets and operating manuals for all of the devices (MSU EZK EZP ESU2), and a service manual only for the EZP.I really need a service manual for the ESU2, because that's the instrument that has the most problems (it only has a problem in the signal attenuation stage and a relay that keeps clicking every 2 seconds). And maybe for the EZK, it works okay, but it's good practice to have your equipment properly documented.Do you know where I can find service manuals for these old devices? Or maybe you know someone who has the ESU2 and can scan/already has scanned the service manual?Or maybe you know something about these devices? Feel free to express your thoughts!Thanks! Looking forward to your replies.

author: Richard9026
author_rank: Newbie
timestamp: December 08, 2018, 09:11:38 pm
content: Nobody knows where I can get old service manuals? Thanks!

author: tautech
author_rank: Super Contributor
timestamp: December 08, 2018, 09:31:43 pm
content: Not saying you will find them here but there's a lot of links to manual repositories to search through here:https://www.eevblog.com/forum/repair/repair-documents-and-links-sticky-me-please-mods/

author: LUBER41
author_rank: Newbie
timestamp: November 12, 2023, 11:33:40 am
content: Hello, Are you still interested in help? I am looking for a service manual for the EZK. R&S told me they cannot deliver it any more. It was all digitailised since 1990 and before is not anymore available.
Hilda CJ369 Laser Distance Finder - Page 1
Forum section: electronics / testgear

author: PinheadBE
author_rank: Regular Contributor
timestamp: November 11, 2023, 11:57:46 pm
content: Hi,Has anyone got the opportunity to test this device (The CJ369 version) ? What about the precision ?Thankshttps://www.aliexpress.com/item/1005005782599907.html
Instruction Manual for Tektronix Quickstart III Training/Demo Board wanted - Page 1
Forum section: electronics / testgear

author: calibrationfixture
author_rank: Regular Contributor
timestamp: November 11, 2023, 06:29:52 am
content: Hi to All,Spotted on eBay a Tektronix Quickstart III Board:https://www.ebay.com/itm/176016821828I have the same Board, but never managed to locate its Instruction Manual. Anybody?Thank you in advance.Calibrationfixture

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: November 11, 2023, 07:26:21 am
content: I swear I saw a page on these educational tek boards on w140! But I can't seem to find it now. Who knows? I might be going insane but I've seen these tek boards somewhere...
How to clear error logs on a Tek MSO/DPO 3000 series? - Page 1
Forum section: electronics / testgear

author: Jwalling
author_rank: Unknown
timestamp: July 16, 2015, 10:22:33 am
content: Hello,Does anyone happen to know how to clear the error logs on a Tek MSO/DPO 3000 series? I have an MSO3054 that has a number of front panel error messages from 2010 that I'd like to get rid of. I posted this question on Tek's web forum and the Tek application engineer responded that it can only be done at a service center.http://www1.tek.com/forum/viewtopic.php?f=5&t=6497&sid=d0449cf3f28070e57348d9f976d3df18I gotta believe that this is *not* really required...Thanks!Jay

author: Jwalling
author_rank: Unknown
timestamp: July 25, 2015, 01:19:34 pm
content: So, I think I could probably find the errorlog if I could gain access to the filesystem via telnet.Looking through the version 2.40 firmware from Teks site.Inside the image is the actual firmware in a file called filesystem.tar.gzIn the directory /etc/init.d is a file called rcS, is the following bit:# We no longer start up the micro telnet daemon for security reasons.##/usr/share/tek/utelnetd -dI could modify this to enable telnet, but utelnetd does not exist anywhere in the file system so Tek must have removed it at some point.Oldest firmware on Teks website is 2.31, but this firmware does not have the telnet daemon either.If anybody has some older firmware they could take a look at, perhaps it was in earlier versions?Jay

author: tautech
author_rank: Super Contributor
timestamp: July 25, 2015, 08:02:20 pm
content: Quote from: Jwalling on July 16, 2015, 10:22:33 amWhy?As long as I'm aware, ~10yrs , error logs have been part of the Tek UI.It's part of the equipments history, little different to error logs on a PC IMO, what good reason is there to delete them.

author: Jwalling
author_rank: Unknown
timestamp: July 26, 2015, 10:55:27 am
content: Quote from: tautech on July 25, 2015, 08:02:20 pmWell, there's over 210 errors of the same type which occurred in a short period of time before the issue was repaired. To look at the error logs recent entries takes a large number of page down button presses. Just a PITA I guess.Jay

author: dom0
author_rank: Super Contributor
timestamp: July 26, 2015, 11:02:40 am
content: UI design failure, logs should almost always start with the most recent entry.

author: rauldm
author_rank: Regular Contributor
timestamp: November 11, 2023, 05:28:39 am
content: Hi, I hope I can help you.1 connect your scope to ethernet port and configure network.2 Enter in the scope web interface with ip address asigned.3 go to Data menu in web interface and put your cursor in command edit box4 send :PASSWord INTEKRITY then :MFG:MODe 15 In the scope interface open utility menu and go to "Self Test" then go to "Error Log", Now your only need press "Erase Log" and ready.I had same problem, I put a latin keyboard and oscilloscope generated a lot of error, same error name and code.

author: Jwalling
author_rank: Unknown
timestamp: November 11, 2023, 09:47:11 am
content: Thank you! I no longer have the scope, but that will be useful in the future.
HP 3403A/B/C (Thermopile 0853-0014) What is it? - Page 1
Forum section: electronics / testgear

author: ocklawaha
author_rank: Newbie
timestamp: March 25, 2020, 02:44:26 am
content: Hello everyone! My first post on EEVBlog!I got my hands on an old HP 3403A RMS Voltmeter. Amazing little instrument design.She powers up on the bench fine. The 70's LED displays all work and controls seemed responsive.Trouble came in on the actual input test. The AC function doesn't read. DC input no issues.On tear down, I believe I located the culprit. It has what HP called at the time TCIa/b THERMOPILE (HPPart#0853-0014). It is a custom component from HP. I can't find any data on this can.If anyone has a datasheet or even a description for that matter, it would be much appreciated.Here are a few links to photos of the piece and associated circuitry.https://postimg.cc/gallery/32dc5pNThanks!Mitch

author: TimFox
author_rank: Super Contributor
timestamp: March 25, 2020, 03:12:21 am
content: A thermopile is a series connection of thermocouples (to increase the voltage). Thermal rms meters work by heating two matched thermocouples/piles: the input voltage heats one (through a heating element resistor) and a servo heats the other to produce the same thermal emf. Measuring the dc voltage on the second heater (when the servo balances the two temperatures) yields the rms value of the input, since the two power values are equal. It would be very difficult to fabricate a replacement.

author: appsman
author_rank: Contributor
timestamp: November 11, 2023, 12:50:04 am
content: I know this post is 3 years old, but I found it while researching the HP 0853-0014. I found some in a pile of parts. I have these devices if you still need them (for cost of postage only). Contact me if you can still use them.

author: doktor pyta
author_rank: Frequent Contributor
timestamp: November 11, 2023, 07:57:09 am
content: https://www.eevblog.com/forum/testgear/hp3403c-marvels-(photos)/msg3349034/#msg3349034
HP 8591A add a Tracking Generator - Page 1
Forum section: electronics / testgear

author: Crambone
author_rank: Frequent Contributor
timestamp: February 11, 2023, 10:26:39 pm
content: I have a good working HP 8591A and a friend gave me all the parts to add the tracking Gen. my question is after adding everything will the firmware automatically recognize the option?Andrew

author: 2nOrderEDO
author_rank: Regular Contributor
timestamp: November 08, 2023, 03:37:21 pm
content: Did you tried installing the generator? It could be that the FW will automatically recognize the tracking generator once installed.Best regards,2nOrderEDO

author: ps
author_rank: Regular Contributor
timestamp: November 09, 2023, 08:51:47 pm
content: Quote from: Crambone on February 11, 2023, 10:26:39 pmYes, it is recognized automatically.There should be a sticker with two calibration coefficients ("SLOPE" and "OFFSET") somewhere in the donor unit. Keep this in a safe place when you remove the tracking generator.
Panasonic Audio Analyzer VP-7721A - Page 1
Forum section: electronics / testgear

author: soundspirits
author_rank: Newbie
timestamp: November 09, 2023, 04:08:03 am
content: A series of question, not really related to each other:Can anyone tell me the years that the 7721A was made? It seems to be the 80's but it would help to know the actual range of years. Is there anyway to tell from the ID/serial number what exact year it was manufactured? I even found a very in depth article about the history of Matsushita/Panasonic company, almost year by year of what they did/made, but there isn't any mention that they ever even MADE test equipment.I can't find anything technical about this Panasonic analyzer online except 2 versions of the same manual one numbered 2, and one numbered a vers 3, and they are too general for the troubleshooting I need to do. (under certain circumstances, the two meter needles will peg out at maximum and will not unlock themselves. I have refloated many solder joints and replaced a lot of old electrolytics (some were leaking). Touching the white band of wires inside though will break the lock, the relays will click again, and the needle comes back to where it should be. But where i need to press on those wires changes, so it's not a consistent point.
Min, Max, Average BM235 BM786 - Page 1
Forum section: electronics / testgear

author: Szumi
author_rank: Contributor
timestamp: November 10, 2023, 06:34:33 pm
content: I was playing with an esp32 writing code to average an input. I thought I'd take my EEVBlog BM235 to average the input as a sanity check.It was immediately apparent that my program had a different time before ittossed old readings than the meter. Well that made me wonder how many samples does the meter take and over what time? So I RTFM'd. I didn't find the information.Does anyone know? I also have a BM786 so I'm curious about it also.Thanks

author: alm
author_rank: Super Contributor
timestamp: November 10, 2023, 07:22:47 pm
content: I'd think it keeps collecting until you reset or cancel the average etc. For min and max it's trivial, and for average the meter should just store the sum of all values so far and the number of values, and update both and then calculate avg = sum of all readings / number of readings.

author: mwb1100
author_rank: Frequent Contributor
timestamp: November 10, 2023, 07:25:02 pm
content: The BM235 has a display update rate of 5 per second (nominal) - so every 200ms give or take. This might also apply to the updates for min/max/avg. Also keep in mid that the average is a "rolling average of the previous 16 readings" and the "average reading is flushed if the new reading is greater than +/- 16 counts from the previous average value".Try doing the same on the ESP and see if you get matching results.

author: mwb1100
author_rank: Frequent Contributor
timestamp: November 10, 2023, 07:32:13 pm
content: The BM786 manual gives a table of the min/max/avg update rates (which differ per mode). For DCV it says that the update rate is 10/sec (nominal).It doesn't seem to mention the number of samples used in the averaging or if/when the average is cleared when the reading has a "large" change.

author: Szumi
author_rank: Contributor
timestamp: November 10, 2023, 10:19:56 pm
content: I'm going to have to solder this circuit together. My solderless breadboard or jumpers are not making a reliable connection. Thanks for the replies so far.EDITI soldered the connections together and I have stable connections. It seems at this point that either Brymen meter is averaging over a much longer time. It is past my bed time. I'll try to record some data points tomorrow and plot them.
Fluke 175 backlight mod question - where is this phantom diffuser? - Page 1
Forum section: electronics / testgear

author: defcon.klaxon
author_rank: Newbie
timestamp: November 07, 2023, 12:48:25 am
content: Hi all,I've been doing some searching around for how to mod my Fluke 175 to add a backlight, and I've found a few threads here that have given me the vast majority of what is needed but the one thing I've heard mentioned but can't find any info about is the diffuser used to evenly spread the backlight across the display. I've looked through forums, Youtube teardowns, eBay and AliExpress, and general Google searches but I can't seem to find *any* info regarding this supposed phantom diffuser. Can someone help figure out what this part looks like, and if it's available as a part to order? I was also thinking I might be able to 3d print it in clear filament if I can get the dimensions.Thanks!

author: Arhigos
author_rank: Regular Contributor
timestamp: November 07, 2023, 12:56:41 am
content: You can disassemble any broken LCD from any other electronic device and pull that part, bend it with hot air gun and cut with dremel or Xacto knife..
Fuse source... - Page 1
Forum section: electronics / testgear

author: BillyO
author_rank: Super Contributor
timestamp: November 06, 2023, 11:21:49 pm
content: Does anyone have a reasonably priced source for the 400ma @1000V fuses for the BM786?Even 600V would do me fine. It will never even see 600V.

author: tautech
author_rank: Super Contributor
timestamp: November 06, 2023, 11:41:39 pm
content: Daves shop ?https://www.eevblog.com/product/multimeter-fuse-pack/

author: BillyO
author_rank: Super Contributor
timestamp: November 06, 2023, 11:46:52 pm
content: They've been out of stock since I got my meter over a year ago.Plus the shipping form Oz to The Great White North kind of messes up the economics of the situation.

author: bdunham7
author_rank: Super Contributor
timestamp: November 07, 2023, 12:17:29 am
content: Bel Fuse, sold by Mouser.https://www.mouser.com/datasheet/2/643/ds_cp_0adbx_series-1664157.pdfYou might get the 600mA version just for the lower burden, I think it will still blow in time if you overload the meter.Or you could just put in a 500mA standard 3AG glass fuse, or even an MDL (slo-blo) if you want to minimize nuisance events. These have an interrupt rating of 10kA at 125VAC, so adequate unless you go in the panel or a 240V circuit.

author: BillyO
author_rank: Super Contributor
timestamp: November 07, 2023, 12:47:13 am
content: I have a 500 mA @ 250V glass fuse in there now. The meter may actually be used in my breaker panel at some point, but likely not to measure mA. Even still, it would be wise to have a better fuse in it. Thanks for teh link to Mouser. I'll put some on my next order.

author: mwb1100
author_rank: Frequent Contributor
timestamp: November 07, 2023, 06:46:43 am
content: Welectron sells anexact match SIBA 7017240.0,4(not much surprise since they're a dealer for many Brymen models) for 7.14€ excl. VAT, but shipping to the US would be 20€ so it would only make sense as an add-on if you were buying something else.There are also these options that would probably work better cost-wise in the US - though they aren't an exact match (500mA instead of 400mA):-500mA SIBA 7017240.0,5 quantity 10 for $16-500mA SIBA 7017240.0,5 quantity 2 for $11-500mA SIBA 7017240.0,5 quantity 1 for $7.50That is if you trust they aren't fake (the listings are on Amazon, but Amazon isn't the vendor for any of them). I have no idea how much counterfeiting of SIBA fuses goes on. I wouldn't expect much, if any, but what do I know?One difference in the specs between the Bel Fuse and SIBA fuses is the Bel IR is 10kA while SIBA's is 30kA. I honestly don't know how important that number is.SIBA 7017240 family fuses datasheet

author: coromonadalix
author_rank: Super Contributor
timestamp: November 07, 2023, 07:10:17 am
content: same herei use 500ma 600ma fuses for the 400ma ranges, they blow too easily with an small overloadbecause here they cost a mere 10$ a fuse FLuke cough cough
Fluke 45 battery option, Li-Ion replacement - Page 1
Forum section: electronics / testgear

author: robert.rozee
author_rank: Frequent Contributor
timestamp: November 09, 2023, 04:12:37 am
content: hi,i recently bought a Fluke 45 with battery option, but of course the lead-acid batteries were long dead. now i'm thinking about ways of getting it running on battery power again, but instead using 18650 LI-Ion cells. has anyone out there tried this? did you modify the existing battery charging system?; build an alternative system?; just fit batteries and use an external charger?; or just bring out the 7-35v DC input to a pair of banana jacks on the back panel for using an external battery pack?at the moment i'm inclined towards using 8x 18650 cells fitted internally, connected as 4 strings of cells (8v approx) combined together with 4x schottky diodes (one for each string). then a rather complex 'conservative' charging system using 8x B0505S isolating modules (5v DC-DC, 200mA each) and 8x TP4056 charge controllers feeding each cell separately via a schottky diode that drops the TP4056's 4.2v output down to a 3.95v full charge voltage. overall, charging would then be terminated based upon a micro monitoring the input current into each of the B0505S and shutting individual modules when current draw falls below a certain level or a timeout occurs.the TP4056 modules i'm looking at using cost around 50 cents each and include onboard over- and under-voltage lockouts managed by DW01A's. while the TP4056 has a preset maximum charging voltage of 4.2v, with a series 1N5817 schottky diode in the -ve connection between TP4056 and the BMS circuitry each cell should see about 3.95v at a charging current of 200mA or less. the idea of this is to extend cell life while still yielding perhaps 70% of usable capacity. 8 x 2000mA.h x 3.7v x 70% = 40wh. the old lead-acid battery pack was only around 20wh.any useful suggestions or other constructive input would be much appreciated before i proceed further...cheers,rob :-)
So... is the 3720-MTC-3 cable magic? Over 1000 EUR for it. - Page 1
Forum section: electronics / testgear

author: daqq
author_rank: Super Contributor
timestamp: November 06, 2023, 08:31:44 am
content: Hi,We're looking over the options of buying a DAQ system. So far the best option for our needs seems to be the Keysight DAQ970A with a bunch of cards. But I've also been looking into others, such as the Keithley devices. Some look great, but one thing stood out:https://www.newark.com/keithley/3720-mtc-3/cable-assembly/dp/59T7977?MER=sy-me-pd-mi-acceOver 1000 EUR for 3 meters of chunkier cable with D-subs on each side? Is it a magic cable? Does it grant wishes? It's basically an interconnect (1 of 2) between a card (which is cheaper than 2 cables) and a terminal box (which is cheaper the cable).Is there something special about the cable?Thanks,David

author: Fungus
author_rank: Super Contributor
timestamp: November 06, 2023, 09:21:06 am
content: 300 Euros per meter for a 78-core cable? Plus two connectors? That's a bargain!Is it the same as this?https://www.aliexpress.com/item/1005004295959810.html
Rigol 1054Z 2nd hand , looking at trial screen options ? - Page 1
Forum section: electronics / testgear

author: KD0CAC John
author_rank: Frequent Contributor
timestamp: November 06, 2023, 08:20:18 pm
content: Looking at a 2nd hand 1054Z , estate sale - so can not talk to last user .All the options the screen shows ended .On some other gear I have read about making trial options getting opened to being turned on past trial period .Most of what I remember was doing hacks before trials ended .So looking at this unit - the question in mind is if anyone has been able to turn the options on - full time ?Thanks all

author: RoGeorge
author_rank: Super Contributor
timestamp: November 06, 2023, 08:25:38 pm
content: All the options in DS1054Z can be unlocked, as if it the instrument were a full-option DS1104Z.DS1054Z and DS1104Z have the same hardware and the same probes, only that DS1054Z has some software limitations from the factory. All the limitations can be removed, and all the options can be unlocked permanently, no matter if they show expired or not.

author: Fungus
author_rank: Super Contributor
timestamp: November 06, 2023, 08:54:36 pm
content: Quote from: KD0CAC John on November 06, 2023, 08:20:18 pmYes, it's easy.Just go to this web page and generate your keys:https://gotroot.ca/rigol/riglol/
low frequency AC coupling box BNC? - Page 1
Forum section: electronics / testgear

author: coppercone2
author_rank: Super Contributor
timestamp: November 03, 2023, 07:07:25 am
content: I want to buy a AC coupler box. like a little box with BNC connectors and some caps in it. Like a thru.Any part # ?I mean like a nice small metal one I can stick on a shitty function gen that has a DC offset that is messing with stuff.I can make one with a pomona box. But I was hoping there is some part# that can be cheap on ebay (random accessory)

author: alm
author_rank: Super Contributor
timestamp: November 03, 2023, 11:42:46 am
content: Spectrum analyzers often use DC blocks. I imagine you can find those for affordable prices, although the cut off frequency may be too high (you don't specify low frequency).You'd have to find an instrument that uses these as accessories so they are made in large quantities. Maybe for audio?

author: coppercone2
author_rank: Super Contributor
timestamp: November 04, 2023, 12:37:21 am
content: yeah I meant a low frequency one, I excluded DC blocks because I associate that with at least MHz signals.I kind of wonder how 2x wet tantalum capacitor would work in a high value one. That might even work for coupling an amplifier to a higher power load. The leakage is really low.. might work?
LCR Kevin clip for HP 4263A - Page 1
Forum section: electronics / testgear

author: MrArthegor
author_rank: Newbie
timestamp: November 08, 2023, 06:15:40 pm
content: Hello everyone,I have recently buy on eBay an HP 4263A LCR meter, my first LCR Meter. It come with no Kelvin clip or any kind of fixtures. With my previous research I thought that any 4 BNC Kelvin cable would be good but with some extent research it seem to need specific things like all shield need to be grounded together.Official HP kelvin clip (16089A) is very pricy, even used, more than cost of device itself in my case. So my question is anyone using an HP 4263A or equivalent have other recommendation for some Kelvin clip or alligator clip for a cheap price ? I don't have enough knowledge of this kind of device and I wouldn't want to damage it with some bad cable (I was initially planned to DIY this cable but I wasn't able to find any schematic of 16089A or equivalent).Thank you very much and sorry in advance for my probably difficult to understand English, it's not my native language.
UNI-T UTG9010B - Page 1
Forum section: electronics / testgear

author: trigskraj
author_rank: Newbie
timestamp: July 31, 2015, 03:04:50 pm
content: You can share software for the generator UNI-T UTG9010B. Sponsored manufacturer, unfortunately, are wrong.

author: ProBang2
author_rank: Frequent Contributor
timestamp: July 31, 2015, 04:19:04 pm
content: ??

author: Bob F.
author_rank: Regular Contributor
timestamp: July 31, 2015, 04:38:07 pm
content: I suspect a Google translate Divide by Zorro error...Is the OP asking for a copy of the software because the manufacturer's site download file is incorrect?

author: miguelvp
author_rank: Super Contributor
timestamp: July 31, 2015, 08:49:09 pm
content: So the one here is not it?http://uni-trend.com/UTG9010B.htmlEdit: apparently so, it seems the download and manual is for a 2000 & 3000 series scope.

author: Lightages
author_rank: Unknown
timestamp: July 31, 2015, 08:53:48 pm
content: I have also tried to download the English manuals for the UT171X series, and there is nothing. Uni-T also does not answer emails it seems.

author: miguelvp
author_rank: Super Contributor
timestamp: July 31, 2015, 09:06:00 pm
content: No software but at least this link has the actual manual for the UTG9010BS/DS serieshttp://www.uni-trend.com/en/product/Signal_Sources/UTG9000_Series/2014_0725_712.htmlEdit: Download link requires a registered memberhttp://www.uni-trend.com/plus/list.php?tid=222I do have a UNI-T DMM but I didn't register to their site yet.

author: Wayland
author_rank: Newbie
timestamp: November 03, 2023, 03:42:55 pm
content: HiI realise that I'm coming to this topic very late as I see you finished this chat in 2015!I've just bought a UNI-T UTG9010BS in excellent condition, it seems to work OK and I have worked out how to make it do what I want, which is to AM modulate an IF frequency, but it would be nice to have a manual.The UNI-T website has no mention of the product and the link posted here goes nowhere.Does anyone have the .PDF that they could email to me?best regardsWayland Twiston Davies

author: coromonadalix
author_rank: Super Contributor
timestamp: November 03, 2023, 04:06:56 pm
content: https://www.manualslib.com/download/2585259/Uni-T-Utg9000t-Series.html
FY3200S internal impendance problem/modification - Page 1
Forum section: electronics / testgear

author: Pygmalion
author_rank: Regular Contributor
timestamp: November 03, 2023, 03:58:07 pm
content: I have noticed that at high output currents (large voltage amplitude + small resistance load) the internal impedance increases drastically. For example, for an amplitude of 10V (20Vpp) and a 10Ω load, the internal impedance is about 100Ω (the voltage amplitude on the resistor is only about 1V (2Vpp)). Is there any modification that can improve the performance of the FY3200S in this regard?See also:https://www.eevblog.com/forum/testgear/measuring-the-esr-of-capacitor-with-feeltech-fy3200s/