hybridfree/eevblog-posts huggingface dataset:
HP 54835A scope Calibration failure. - Page 1
Forum section: electronics / testgear

author: magnetchief
author_rank: Contributor
timestamp: January 22, 2024, 02:15:18 pm
content: Hi guys, having an issue with an HP 54835A scope.The HDD had failed and the back light was very dim.Replaced the drive with a preformatted image of a later version.Replaced both backlights.Scope seems to be working well, all 4 channels are fine.I can input an AC signal and it displays as I would expect.It passes all the self tests.But will not pass the calibration tests.I am using a 30cm cable for the tests.Measured the DC output voltage from the aux port. It reads apx 800mv. Never changes even during the cal test. Even when changing the level -2.5 to +2.5 just stays at + .8vAny advice appreciated.
Read 121GW SD card by bluetooth - Page 1
Forum section: electronics / testgear

author: jms019
author_rank: Newbie
timestamp: January 22, 2024, 10:31:13 am
content: Is it possible to log to SD card then later fetch the data over bluetooth ?I cannot find the answer anywhere.Jon

author: Kean
author_rank: Unknown
timestamp: January 22, 2024, 11:09:06 am
content: No, this was never implemented in the 121GW firmware. It has been discussed before, but not sure it is actually "documented".Here are a couple of links mentioning it that I found with a quick search.https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg2690580/#msg2690580https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg4724672/#msg4724672
Rigol DHO924S is on Amazon - Page 1
Forum section: electronics / testgear

author: WA9ONY
author_rank: Newbie
timestamp: November 22, 2023, 06:57:55 pm
content: https://www.amazon.com/Oscilloscope-Frequency-Vertical-Resolution-Generator/dp/B0CGHTLRHS/ref=sr_1_3?crid=W17IY90YZT49&keywords=rigol+dho924s&qid=1700679236&sprefix=DHO924%2Caps%2C143&sr=8-3&ufe=app_do%3Aamzn1.fos.2b70bf2b-6730-4ccf-ab97-eb60747b8daf73 David WA9ONY

author: lunix
author_rank: Contributor
timestamp: January 22, 2024, 11:05:13 am
content: If you like to beta test instead of getting work done. I've had it for almost two days. LOTS of bugs.I just got the RIGOL DHO924S, with the PLA2216 logic analyzer accessory. It's given me the "RIGOL.SCOPE app has stopped" (with a restart button) and the "RIGOL.SCOPE app keeps stopping" (with a close button). And it has LOTS of other bugs in the UI. Also, I received 20 leads and 20 grabbers with the $400 accessory, they show it is supposed to have 32 of each.It should be a very fine instrument- but how many releases past the current v1.01 firmware will it take to make it prductive? It crashed (as above) after just a couple hours of use (and I thought it was bricked until I left it un-powered for a couple of hours), and again tonight after just an hour, but I powered down and restarted (my setup was gone, despite having selected to load the last used setup on powerup). It powers up with Chan 1 enabled, and set as the trigger (I guess, the factory default).Hold off until you can read lots of reviews. The DHO900 series has a lot of promise... but grossly under-delivers. And I get paid to do work that requires a scope, and plenty of other T&M stuff. I have never found a single bug in another piece of T&M equipment. (for decades)
upgrading HP 5328A with Option 010 (05328-60038) - Page 1
Forum section: electronics / testgear

author: guenthert
author_rank: Frequent Contributor
timestamp: January 21, 2024, 05:37:38 pm
content: Years ago I bought a -hp- 10544a ovenized oscillator with attached adapter PCB thinking I could use it to upgrade my -hp- 5328A counter which came with plenty an option, but crucially not option 010, the high stability oscillator. Now the service manual states that all one has to do is remove the old oscillator (this 3 pin device in TO-5 case), insert the adapter PCB with the oven assembly, fasten that to the chassis and bob's your uncle. Well, I tried that, but after turning the power on again, the counter didn't count anymore. That's actually not correct -- itdidcount events (for which one doesn't need a clock), but not the frequency or period of an external signal. The count remained 0 (occasionally the last digit jumped one, as there seems to be an off-by-one error happening when changing functions). My heart sank, but there was no magic smoke and eventually the oven became warm to the touch. Such encouraged, I poked around with the oscilloscope and did find a perfect 10MHz on pin 1 of the edge connector to the oscillator. So the oscillator was oscillating, just the counter wasn't counting.A reader familiar with the counter might have noticed that option 010 bears actually the -hp- part number 05328-60018, not -60038. The riddle's solution lies in the fact, that -hp- produced the counter also for the military with slight variations. Afaict, the military version has always the Option 010 built in (there called A3A1), automatically senses the presence of an external reference signal and offers additional outputs for the internal 10MHz reference and a by 10 divided reference.With that tidbit of information and the schematic of the A3A1 PCB (05328-60038) from , the schematic of the counter (which thankfully are provided by Keysight) made sense and it was easy to deduce that the wire-bridge, which connects pin 6 of U16 with pin 13 of the edge connector to the option 010 board had to be cut and rerouted so that pin 6 of U16 connects to pin 11 of the edge connector instead.I did just that and viola, it actually works. Took me a while to gather the necessary info from the Interwebs, so if someone finds himself in the same situation (however unlikely that might be), this hopefully gets him/her on the way sooner.PS: the -60038 is actually the preferred option, as it allows for electronic frequency control (the 'fine tune' multi-turn potentiometer on the option PCB (it took about five whole turns clockwise to remove the 30pbb frequency error seen in the picture)https://radionerds.com/images/9/9a/TM_11-6625-2941-14%26P.PDF
Owon XSA-810-TG Spectrum Analyzer funny business - Page 1
Forum section: electronics / testgear

author: jrgandara
author_rank: Contributor
timestamp: October 05, 2023, 05:40:14 am
content: Hello all!Anyone also using these Owon Spectrum analyzers? I had the Rigol TG-815 and the Siglent 3021. Both very capable for duplexer adjustments. Used to reach more than -100dBm with those but not quite with the Owon although the specs says -160 DANL. Mine lock the attenuation in 20dB and I could not manage to change to zero. Also the RBW will not go under 3KHz (needed to increase the sensitivity) and the deep of the notch is very noise even at -90dBm. I checked Owon web site and found nothing about firmwares updates. Maybe things work different with this Owon and I'm making mistakes.Anyone got one of those? Any suggestion?Thanks in advance.JR

author: minsik
author_rank: Contributor
timestamp: January 25, 2024, 11:12:56 am
content: Hidid you contact Owon for any firmware updates even though they have not put on the web site?Did you do more duplexer or cavity filter adjustments and form any other opinions?Do you use for general radio communications work, ie FM vhf/uhf?Only because the Owon XSA810-TG seems the best value currently for me as a hobbyist.thanks Minsik.

author: RFDx
author_rank: Regular Contributor
timestamp: January 26, 2024, 02:40:54 am
content: Quote from: jrgandara on October 05, 2023, 05:40:14 amOwon specifies the isolation between tracking generator (@ 0dBm output) and RF input at only 60dB, that's why I can't imagine you being able to reach your -100dBm target. It really doesn't matter how far down th DANL can go or how narrow the resolution bandwidth can be made while the TG is turned on.
Missing plastic cap on input probe on the DHO804 - Page 1
Forum section: electronics / testgear

author: mkosett
author_rank: Contributor
timestamp: January 20, 2024, 11:23:27 am
content: I just got my DHO804 and i see no plastic cap on the input probe as how it should be in the attached picture below. Should i be worried? .... I bought it in India, does it have to do something with that?

author: Grandchuck
author_rank: Super Contributor
timestamp: January 20, 2024, 02:07:48 pm
content: My guess is that it was returned.

author: DaneLaw
author_rank: Frequent Contributor
timestamp: January 20, 2024, 03:38:42 pm
content: Quote from: mkosett on January 20, 2024, 11:23:27 amWorried about what exactly?How did your unit arrive, was it wrapped & sealed - all for your protection.. you should incl. that fundamental info, if people should have any aspect of guessing on your behalf if there is something to be worried about..And why should India as a purchase location be synonymous with missing plastic caps?I don't have a DHOxxx, but got another product from Rigol a month back (sig gen) using the same form factor... it got 6xBNC sockets and none of those had plastic/silicone caps.Units fresh out the own - will usually have an official Rigol tear-sticker, alongside thin plastic film...exampled on my unit below, though quite an early unit snxxx000000013

author: mkosett
author_rank: Contributor
timestamp: January 20, 2024, 08:09:28 pm
content: but seal was intact. and also the stock is fresh ( print date of manual is 4th jan 2024)

author: SeanB
author_rank: Super Contributor
timestamp: January 20, 2024, 08:11:29 pm
content: Factory worker left them off during packaging then is the most likely thing. Or they ran out of stock on the line, and thus a few dozen did not get these caps. You can buy them and put them on.

author: mkosett
author_rank: Contributor
timestamp: January 20, 2024, 08:14:47 pm
content: Yes that's quite possible.
Thurlby Thandar TF830 user advice please - Page 1
Forum section: electronics / testgear

author: davebullock
author_rank: Contributor
timestamp: January 19, 2024, 12:50:15 pm
content: HI everyone.I have to time the delay between two pulses to microsecond accuracy and have in my test gear a Thurlby Thandar TF830.I don't have a user manual for this instrument and have failed to find such any detailed operating instructions on the web.I have only ever used this TF830 for measuring RF frequencies not timing.In the past I have used 'timer counters' that had an A and B input such that counting could be started by a pulse on 'A' and stopped by a pulse on 'B'. The resultant delay being displayed on the readout.However whilst the TF830 has a function called A/B RATIO I am not convinced that this is the function I require (or..... if it is, how to set it up).Does anyone out there have experience operating this instrument or have a copy of a USER manual that I can copy please?Thanks in anticipationDave

author: AVGresponding
author_rank: Super Contributor
timestamp: January 20, 2024, 11:18:27 am
content: It's always worth firing an email off to Aim-TTi, their tech support are usually very helpful with manuals for older stuff.

author: Solder_Junkie
author_rank: Frequent Contributor
timestamp: January 20, 2024, 01:22:37 pm
content: See attached service manual, it describes the operation of the counter as well.SJ

author: davebullock
author_rank: Contributor
timestamp: January 20, 2024, 04:35:45 pm
content: HI, Thanks for your replies.Yes I already had the service manual but it doesn't describe how to use the RATIO A/B or exactly what it does?However it doesn't do what I hoped it did, ie, measure the timing difference between a pulse applied to port A and sometime later Port B (which is what I need)Instead I found this on the Fluke website:-RATIO A/BTo find the ratio between two input frequencies, the counter counts the cycles on twochannels simultaneously and divides the result on the primary channel by the result on thesecondary channel.Ratio can be measured between inputs A and B.Back to the drawing board :-)Dave
Tektronix 1740A Waveform monitor > need calibration and firmware recovery disks - Page 1
Forum section: electronics / testgear

author: xymox
author_rank: Contributor
timestamp: January 16, 2022, 12:09:02 am
content: I really need the floppy discs that came with the service manual for the Tektronix 1740A. The lithium battery in the SRAM dies and lots are dying now and there is no way to recover them without these disks that came with the service manual.

author: Manolo Mos
author_rank: Contributor
timestamp: December 28, 2023, 04:51:56 pm
content: I'm in the same case. I have a Tek 1765, I removed the Nvram Dallas DS1225 for to backup the calibration, but when I read the memory, the memory was empty. In the threads about oscilloscope Tek 2465 talks about what happened me, a operational backup memory that is ereased when you remove and try to read it.I see a link for download the Tek 17xx calibration software but it don't work.https://www.tek.com/en/support/faqs/where-can-i-get-1740a-1750a-or-1760-calibration-softwareService manual in page 2-13 talks about a program for to download the calibration data to a PC, nvsave.exe, and for upload, nvrestore.exe. That programs are ideals for to download calibration data for to replace the Dallas nvram DS1225.

author: Manolo Mos
author_rank: Contributor
timestamp: January 20, 2024, 12:15:06 am
content: I've downloaded it onhttps://groups.io/g/TekScopes/files?p=created,,,20,2,0,0These are the filesNVSAVE.EXECONVERT.EXEUPGRADE.EXENVRESTOR.EXENEW_CAL.EXESOFTWARE.BINNEW_CAL.EXE17XX.PRC
Info and help on the Meguro MO-1254A Oscilloscope - Page 1
Forum section: electronics / testgear

author: Igac
author_rank: Newbie
timestamp: January 18, 2024, 02:21:03 pm
content: Hello, I'm new-ish to electronics and found a good deal for a Meguro MO-1254A scope.Does anyone have experience using these scopes do they come with off-the-rack hardware, maybe some tips or manuals?The scope is very well-priced for my region so I'm thinking about pulling the trigger.Thank you guys in advance!

author: Lochstreifen
author_rank: Newbie
timestamp: January 19, 2024, 06:42:45 pm
content: It's a 50 MHz analog CRO with second time base and a well thought out user Interface.It was also rebranded as Gould OS 350, Elenco and Heathkit SO-4251.You can find the manual for the otherwise identical 40 MHz version herehttps://elektrotanya.com/meguro_mo1253_40mhz_dual_channel_oscilloscope_sm.pdf/download.html
I broke my 747 Tube Tester! - Page 1
Forum section: electronics / testgear

author: Wil_Bloodworth
author_rank: Regular Contributor
timestamp: January 19, 2024, 04:16:26 am
content: Well, after replacing all the capacitors and calibrating the machine, I went back to the beginning of the calibration... just to check again. When I got to step #2, the Test 1 button no longer worked. It doesn't seem to do anything at all now. It won't calibrate and it's as if the button no longer works at all. So, my new-old tube tester is now a door stop.I also notice that the two 5W resistors on the board with all the calibration pots are overly hot as well.Any thoughts on how to figure out what I could've broken?Thank you,- Wil

author: pelud
author_rank: Regular Contributor
timestamp: January 19, 2024, 11:31:51 am
content: Try cleaning the contacts for the light bulbs. They are notorious for going bad.You can also get low readings when they get dirty.Edit: Also check that the "signal" wire is not shorted to ground.
Do you recognize this connector? Chauvin Arnaux E14 Current probe - Page 1
Forum section: electronics / testgear

author: diegoperez
author_rank: Contributor
timestamp: February 24, 2018, 02:22:40 pm
content: After searching for a while, I could not find any information about this current probe.It is very similar to the ubiquitouschauvin arnoux E3N current probe, which I think is rebadged under various other brand names.But this one does not have the dc-offset trim pot nor the over-range led indicator. In addition, I think this current probe needs a terminating resistor at the connector end, because the gain seems to be wrong when connected to a 1-MOhm scope input impedance.Any info regarding the connector or the probe will be welcomed.Thanks,Diego

author: 0xfede
author_rank: Regular Contributor
timestamp: February 24, 2018, 09:09:19 pm
content: Hi Diego,it seems to me a lemo connector.Have a look to their site:https://www.lemo.com/enBest,0xfede

author: vtp
author_rank: Regular Contributor
timestamp: February 25, 2018, 09:41:10 am
content: Try Hypertronics D-series, possibly D02.

author: diegoperez
author_rank: Contributor
timestamp: February 25, 2018, 10:44:33 am
content: Quote from: vtp on February 25, 2018, 09:41:10 amWow, that's right. It's a D01 series with 3 contacts (but only two are populated).After comparing the dimensions whith the catalogue, I also noticed a 'D01' engraving mark in the connector, which further confirms it.Thank you!

author: angeeinstein
author_rank: Newbie
timestamp: January 16, 2024, 07:39:43 pm
content: Did you get this probe to work?

author: shakalnokturn
author_rank: Super Contributor
timestamp: January 18, 2024, 10:46:18 pm
content: This also seems to be the same connector I was inquiring about in this topic:https://www.eevblog.com/forum/testgear/dossena-multiver-3-sn-3-phase-network-analyser/msg5096883
rohde & schwarz fsp13 - Page 1
Forum section: electronics / testgear

author: dencyaupin
author_rank: Newbie
timestamp: June 29, 2021, 04:51:08 pm
content: Hello everyone! I became the proud owner of a rohde & schwarz fsp13 Spectrum Analyzer, but unfortunately it does not pass the self test and does not start calibration. Reference signal level 128MHz sees at 0dbm -26dbm! The level of the external 10GHz generator is fully met. Tell me where to dig? Analyzer above 3 GHz works fine.

author: dencyaupin
author_rank: Newbie
timestamp: June 30, 2021, 06:26:19 pm
content: Diode Ring Mixer?

author: dencyaupin
author_rank: Newbie
timestamp: December 19, 2023, 01:27:27 pm
content: Hello everyone, does no one know this diode assembly? I installed BAT15 and everything worked

author: dencyaupin
author_rank: Newbie
timestamp: January 19, 2024, 10:48:32 am
content: Why does no one know the part number for this part???
2000V rated DMM/scope for solar - Page 1
Forum section: electronics / testgear

author: kuon
author_rank: Regular Contributor
timestamp: January 18, 2024, 09:36:25 pm
content: Hello,I am looking for a 2kV rated DMM/scope solution to measure solar strings. Especially to inspect the CPL signal many inverter use. I do not need decoding, only see if it's there and the "look" of it (frequency, amplitude). 100Mhz should be plenty enough.Most strings are under 1kV, but sometimes it is a bit more, and it can be way more when not installed properly, so I want to be safe and have a 2kV capable scope.I don't need anything fancy with features, just something safe, super reliable and rugged.For budget I was thinking <1k$, but as it is important to me, I'm ready to go up to 5k$ if it is what it takes.

author: Martin72
author_rank: Super Contributor
timestamp: January 18, 2024, 09:47:33 pm
content: Hi,Some time ago I was looking for a DMM that can measure over 1500V and found one at Uni-T, but there are also "better" ones from Beha Amprobe.Otherwise I would take a portable scope plus differential probe.Or a portable scope with isolated inputs and a 1:100 probe.

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 18, 2024, 09:51:58 pm
content: Why wouldn't you just get high voltage probes? I have a PR2000B probe that can handle 2kV.

author: BeBuLamar
author_rank: Super Contributor
timestamp: January 18, 2024, 09:56:20 pm
content: The Fluke 393 clamp meter is rated for 1500VDC.

author: Someone
author_rank: Super Contributor
timestamp: January 18, 2024, 09:56:57 pm
content: It is the probe, not the device. But your budget is ambitious.http://www.pmk.de/en/products/5_mm_hochspannungstastkoepfeAs above, a high voltage and high ratio differential probe may be the quickest and cheapest route.

author: kuon
author_rank: Regular Contributor
timestamp: January 18, 2024, 09:59:43 pm
content: Quote from: KungFuJosh on January 18, 2024, 09:51:58 pmI'm fully open to this solution too.I found the CT4072 from cal test. I guess I can look at any portable scope then.

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 18, 2024, 10:15:40 pm
content: Quote from: kuon on January 18, 2024, 09:59:43 pmThat's the best solution. Now you're not limited in scope choice, and if you ever want a different scope, you'll already have the probes you need.
Bug Rigol DS1054Z?  No capital letters when saving with new filename. - Page 1
Forum section: electronics / testgear

author: kosmos
author_rank: Contributor
timestamp: January 18, 2024, 02:51:28 pm
content: Helle, when you take a picture with the DS1054Z using the print button, it is continuously saved in this format DS1Z_QuickPrint....png. If I want to enter a file name, I can switch to capital letters, but when I confirm a letter it still appears small. Is that the case with you too?Does Rigol care about such things? You don't exactly see a lot of firmware updates with them?

author: ebastler
author_rank: Super Contributor
timestamp: January 18, 2024, 06:54:02 pm
content: I have never used custom filenames so far -- always renamed files later on the PC, or pasted the picture into a document right away. But I just tried, and could enter upper- and lowercase letters without a problem. They also do appear correctly in the file name on the USB stick.What firmware version are you on? I am on 04.05.SP2.Regarding your general question "Does Rigol care?": That scope has been on the market for more than 9 years now, and has just been superseded by the DHO800/900 series. (Which does not necessarily mean that Rigol will take it off the market -- they have often continued to sell earlier models, like the DS1000 series which is still available today.) I think it is safe to assume that any bugs which remain now will remain forever.
Bought some attenuators - Page 1
Forum section: electronics / testgear

author: mojoe
author_rank: Frequent Contributor
timestamp: January 08, 2024, 03:54:22 am
content: Taking a chance on an Amazon purchase, since I can easily return them, I bought some attenuators to use with my new TinySA, NanoVNA H4 and LiteVNA 64 (fun stuff to play with and learn). I won't post a link, but if you search for "XRDS -RF SMA Male to SMA Female Coaxial RF Attenuator, DC to 8 GHz" you will find several values. I'm still waiting on some of them, but the 6 dB and 10 dB attenuators arrived today.Of course, the first thing I did was break out the LiteVNA. The H4 only goes up to 2 GHz. I did a full calibration of the LiteVNA from 1 MHz to 8 GHz with 1024 points. The results for both the 6 dB and 10 dB values look good (I checked each pair). Up to about 7 GHz, they are +/- 0.5 dB or less. From 7-8 GHz, +/- 1.0 dB or less.I'd post a screenshot, but I'm having trouble with the NanoVNA Saver software. Perhaps I'm doing something wrong. Later, I'll look around for other software to try.When I ordered the two VNA's, I also ordered the Nooelec attenuator kit, but I wanted more of the 3, 6, 10, 20 & 30 dB values, and these XRDS ones were much less expensive (about $12/pair).I'm just passing this along in case others are looking for some attenuators. I plan on checking every one, when the others arrive, to make sure I don't get a dud.

author: mojoe
author_rank: Frequent Contributor
timestamp: January 08, 2024, 09:07:40 am
content: More testing - I looked at the return loss.Above about 6 GHz the return loss gets worse than -20 dBm. The Nooelec attenuators did the same. Still, higher than I'm likely to ever need.

author: nonlinearschool
author_rank: Contributor
timestamp: January 18, 2024, 02:44:27 am
content: Hey!I just bought some attenuators. I bought one and did notice it was a N-type connector.So I ordered two more today, a 10watt 30dB and a 2watt 20dB. for my tinySA. Frankly I am just kind of in the dark on which ones to buy. I did not, forgot to check the max frequency but I guess I'll find out. I only want to check an assortment of HT radio antennas I bought. and the 5watt and 8 watt HTs. I thought of contacting Joe Smith and ask him since he is so very familiar with this stuff. However I just took a chance and think this time I did OK.Does anyone want a 10watt 30dB N-type connectors? I don't even have that type connector. maybe some old tv coax that I no longer have any reason to use. Does anyone want 100ft of TV coax?

author: rhb
author_rank: Super Contributor
timestamp: January 18, 2024, 04:17:42 pm
content: FYI The SMA connector is only rated for 500 connections before it needs to be replaced. You'd be better off with an SMA-N adapter and N cabling. If you stick with SMA be sure to put M-F "connector savers" on everything. Don't forget to put them on the cables as I did! I've been cutting worn out SMA-M connectors off of cables so I don't use them by mistake.Have Fun!Reg
Agilent/Keysight Bench Multimeter U3402A residual count when shorted - Page 1
Forum section: electronics / testgear

author: uwer
author_rank: Newbie
timestamp: November 05, 2014, 03:24:48 pm
content: Hi everyone, I would like to get some input on the following.At work we use several (5 or 6) Agilent U3402A multimeters. One of them died with an inexplicably defective high current range although the fuse was ok. In another one the low current range died, I am unsure why but that's beside the point anyway. (Both devices were replaced out of warranty at our cost.)Another one of these meters has developed a high residual resistance display. When shorted I have seen anywhere from a little over 1 to more than 70 Ohms.Here is my real inquiry:The replacement devices showed what I consider pretty high residual counts in the AC ranges when shorted, as shown in the attached pics.Our older meters of the same type do not behave like that and pretty much zero out with somewhere between 0 to 7 digits remaining. We have since exchanged two units only to have the new ones behave in the same (bad) way.For a supposedly high quality meter, I don't find these residual counts acceptable. What do you guys think?

author: jpb
author_rank: Super Contributor
timestamp: November 05, 2014, 03:56:00 pm
content: See this thread for a discussion of rms converter noise which I think is relevant to what you're seeing:https://www.eevblog.com/forum/testgear/keithley-2000-trms-converter-noise/

author: macboy
author_rank: Super Contributor
timestamp: November 05, 2014, 08:05:56 pm
content: +1 to what jpb said.This is RMS converter offset. This exact question pops up every so often here. This offset is normal and always present. Some HP gear will display a false zero count when the count is low enough. This is misleading IMHO, but I understand the RMS converter noise issue and don't expect to see zero.I have a few Keithley 2001's on my bench, these are $5k meters. They do the same thing.Very few meters do not have this issue. The Agilent 3458A comes to mind. It can do 100000 samples per second at 4.5 digits, and compute the RMS from them. It can also use an RMS converter in the conventional way, and it will then exhibit this offset issue.

author: uwer
author_rank: Newbie
timestamp: November 06, 2014, 04:45:40 pm
content: Very enlightening.Thank you for your comments. You saved me a lot of trouble arguing with our supplier.

author: macboy
author_rank: Super Contributor
timestamp: November 06, 2014, 06:09:51 pm
content: One more comment on this,do not null/zero out this offset. The applied AC voltage does not add algebraically to this offset, it adds as RSS - Root of Sum of Squares. So, hypothecially, if you get 0.200 mV with the inputs shorted, and then apply 10.000 mV, the display will be sqrt(10^2 + 0.2^2) =10.002 mV,not10.200 mV. If you had "nulled" out the offset, then applied the 10.000 mV, the display would read 9.800 mV, a large error.

author: lern01
author_rank: Regular Contributor
timestamp: January 18, 2024, 09:45:56 am
content: Quote from: macboy on November 06, 2014, 06:09:51 pmHow to enter calibration mode for u3402a. Thanks!
HP 8903a replacement options - Page 1
Forum section: electronics / testgear

author: akabek
author_rank: Contributor
timestamp: January 18, 2024, 01:23:37 am
content: I have a HP8903a running Pete Millet's software that I use for audio repair/testing. Space is an issue for me so I am contemplating looking for a small setup. Are there other options in the $500 range? What are the thoughts on the Analog Discovery, Quant Asylum? Any other options out there?
SDS1202X-E Trigger Serial doesnt work? - Page 1
Forum section: electronics / testgear

author: STM55
author_rank: Newbie
timestamp: January 16, 2024, 02:13:44 pm
content: Hi! I cant trigger spi signal (1 burst in 2 seconds)Latest firmware 1.3.27Spi in: mode 3Data sent: 0xF0Trigger set to -> serialdata : 8Clock:CH1: edge:falling treshold 1VMOSI:CH2 treshold 1Vbits set to: xxxx xxxxorder: MSBAuto semms to give short blip on screen, normal mode does nothing, single mode does nothing.I can trigger this signal in trigger: edge, it looks ok.Edge:

author: tautech
author_rank: Super Contributor
timestamp: January 16, 2024, 08:21:17 pm
content: Seems obvious you have data that isn't coinciding with the clock.No wonder a Serial trigger is confused.

author: nctnico
author_rank: Super Contributor
timestamp: January 16, 2024, 08:40:06 pm
content: Buzzz. Wrong answer. That data looks just fine. Keep in mind that with SPI data can be send/captured on rising or falling edges. In this case data is sent on rising edges and captured by the device on the falling edges.The right answer is likely that just like serial decoding, SPI decoding got messed up as well on a recent firmware release on this oscilloscope. The OP can try to downgrade to a previous firmware version to see if that works.

author: tautech
author_rank: Super Contributor
timestamp: January 16, 2024, 10:26:19 pm
content: Quote from: nctnico on January 16, 2024, 08:40:06 pmData is Ch2, and about 4 clock cycles of it are before the active the clock period.Something is wrong with the OP's setup.

author: ebastler
author_rank: Super Contributor
timestamp: January 16, 2024, 10:44:41 pm
content: Quote from: tautech on January 16, 2024, 10:26:19 pmIt should not matter what the data line does before the clock pulses start. There is valid data while the clock ticks, and it does represent the intended value of $F0, sent MSB first.However, it looks like the data line changes exactly on a falling edge of the clock. If that is meant ot be the active clock edge, there may be an ill-defined state at that point. (If a hold time is required after the edge -- not sure whether that is the case?)

author: 2N3055
author_rank: Super Contributor
timestamp: January 16, 2024, 11:08:43 pm
content: SPI supports 4 modes.Mode 3 is clock idle state high, sample on rise edge, clock out on falling edge.So data edges will be in synch with clock falling edge, and sampled on next rising clock edge.Most commonly used mode is mode 0. Means clock is idle low.When you use CS too it is obvious what framing is. You only need to set what clock sampling edge is.With only 2 ch used, you need to set framing by timeout.for mode 3 you need to set clock rising and set proper timeout

author: 2N3055
author_rank: Super Contributor
timestamp: January 16, 2024, 11:14:43 pm
content: Just a note.Useful practice is to set decode first with single (or about one) data frame captured by using single edge trigger. You set decode setup to the point it decodes right. Then copy setup to trigger.That way you have verified the setup beforehand.
Suspiciously Cheap HP 8722ES 40 GHz Network Analyzer - Page 1
Forum section: electronics / testgear

author: EE54
author_rank: Regular Contributor
timestamp: January 16, 2024, 04:15:48 pm
content: Came across this interesting listing on EBayhttps://www.ebay.com/itm/166550392927?hash=item26c72d505f:g:ocwAAOSwEi5lpB5VThere's no way anyone who somehow owns a 40 GHZ VNA would sell it for that cheap.The seller page look kinda strange too. 50% Satisfactory rating, 4 items sold total and the VNA is the only current item listed.What do you guys think? Obvious scam or a clueless owner?

author: sorenkir
author_rank: Regular Contributor
timestamp: January 16, 2024, 04:39:12 pm
content: A quick Google Image search gives the answer:https://cogwell.com/products/agilent-8722es-vector-network-analyzer-50mhz-to-40ghz-opt-010-1d5?variant=39781836030130Michel.

author: EE54
author_rank: Regular Contributor
timestamp: January 16, 2024, 04:53:46 pm
content: Ah, thanks.I’ll report the listing in a few minutes.Maybe message the seller for kicks.

author: EE54
author_rank: Regular Contributor
timestamp: January 17, 2024, 06:56:33 am
content: Hmm, what a shame
AWG2020: I need help identifying components on A3 board - Page 1
Forum section: electronics / testgear

author: piranha32
author_rank: Unknown
timestamp: February 02, 2023, 05:43:56 am
content: Hi!I've got an AWG2020, which did not power on. After cleanup of the boards, replacement of all 22uF caps and repair of corroded traces the generator sprung back to life, except one failure in the output circuitry. It looks like the error is caused by damage on the A3 board. It was most likely caused by leaking caps, but this time the damage to the traces is not as extensive as on other boards, but the SMD resistors around the input circuitry are damaged. The top protective layer peeled off exposing the resistive traces, and along with the top layer the markings also disappeared.Can somebody, please, take a picture of this section of the board with resistor markings readable?

author: gianrisa
author_rank: Contributor
timestamp: November 23, 2023, 10:54:19 pm
content: Hey did you manage to save it do you still need a pic I can do it for you I have the 2021 but I think the frontend is similar

author: piranha32
author_rank: Unknown
timestamp: November 24, 2023, 01:32:32 am
content: Hey! Thanks for replying!I will appreciate if you could take pictures of your board. The more, the better

author: gianrisa
author_rank: Contributor
timestamp: November 26, 2023, 10:35:10 am
content: Hi here few shots, if you need I can add even more you let me know what you need.I'm looking for the option 4, still no luck till now.

author: RPP
author_rank: Contributor
timestamp: January 16, 2024, 07:35:12 pm
content: I just finished up an AWG2020 that had output issues among other things. . . . Info here:https://www.eevblog.com/forum/testgear/tektronix-awg2020-no-output/I have photos if you need more.Rich
How to turn on ERES SDS2104X Plus - Page 1
Forum section: electronics / testgear

author: swmcl
author_rank: Contributor
timestamp: January 16, 2024, 10:18:44 am
content: Hi all,I'm reading the manual and expecting to see an option for ERES in the 'Acquire' menu.I aint seein it !How does one use ERES on this scope please ? Software version 1.5.2R1 Hardware version 05-05Cheers !

author: tautech
author_rank: Super Contributor
timestamp: January 16, 2024, 10:32:29 am
content: Quote from: swmcl on January 16, 2024, 10:18:44 amIt's in the Math menu.QuoteEngage the additional bits required from the ERES menu.QuoteOutdated.Install the latest from here:https://int.siglent.com/download/firmwares/?ProId=53There is a later version with the beta testers currently however I don't yet have an ETA.

author: swmcl
author_rank: Contributor
timestamp: January 16, 2024, 10:47:06 am
content: Thank you Tautech !
From a cheap DMM to a custom panel meter: detaching LCD and other hints. - Page 1
Forum section: electronics / testgear

author: jchw4
author_rank: Regular Contributor
timestamp: January 15, 2024, 10:25:07 am
content: I recently got an old variac and started looking for a modern volts/amps meter. There are cheap panel meters around but they are very limited. The $20 Zotek (ZOYI, Aneng, etc...) meters are so much better!So I thought of basically making a panel meter from a cheap DMM.The first issue seems to be detaching an LCD and making a "display cable". But I am sure somebody has already tried that.Any hints?I could not find any zebra adapters, it will probably require a custom PCB. Is it as easy as it sounds?Did anybody try making a custom LCD zebra strip mount? Are there any tricks that I should better know before trying to design something myself?(Like should the display PCB match the full size of the LCD or is it enough to cover only the contacts for mechanical rigidity? How much do I need to compress the zebra strip?)

author: janoc
author_rank: Super Contributor
timestamp: January 15, 2024, 02:44:17 pm
content: Quote from: jchw4 on January 15, 2024, 10:25:07 amWhy would a variac need more than a basic voltage/current meter with a single range?What are you planning to do with it? Measure capacitors? Probably not, right? Variac is not a multimeter, if you need more accuracy/features for whatever reason once in a blue moon, connect a multimeter to the output!

author: enut11
author_rank: Super Contributor
timestamp: January 16, 2024, 05:28:08 am
content: It has been done before. Look at this thread:https://www.eevblog.com/forum/projects/using-a-fixed-range-ac-voltmeter-with-variable-input/msg2801118/#msg2801118BTW, digital meters are slow to respond to changes so I also have an analog AC meter to monitor the current. When powering up suspect equipment I start at zero volts and slowly wind up the AC while I monitor the current.

author: Kleinstein
author_rank: Super Contributor
timestamp: January 16, 2024, 06:32:15 am
content: Quote from: enut11 on January 16, 2024, 05:28:08 amThe speed depends on the AC conerter: the analog RMS converter like AD637 are relative slow, as they need to filter out the ripple quite well to get really RMS at mains frequency.Some modern meters (both higher grade bench top and rel. low priced handhelds) use digital RMS and can be quite fast with AC, not much slower than with DC. The downside with the handheld DMMs with digital RMS (e.g. UT133) is there limited bandwidth (e.g. 1-5 kHz).
HP8920 displaying over 1.5 Megawatts !!! - Page 1
Forum section: electronics / testgear

author: VE2UM
author_rank: Contributor
timestamp: January 15, 2024, 09:49:24 pm
content: Hi all...This is a weird one...I have been servicing HP8920's / 8922's for years for a radio shop but this one is above all...When connected to a 25W or less transmitter, the RF power display is excellent (particularly for a test set of this age !) but as soon as i use a radio above 25 - 30 Watts, the display comes completely out of this world.Power levels of about 1500000 Watts, 92 dBm, or 9000 RF volts !!! All scales seem to correlate within eachother but with an incomprehensible +47 dB offset !!!!Suddenly, when RF drive rises from 25 Watts to 30 Watts, no glitch, no warning, from 30 to 1500000 Watts !Outside of that offset, everything else is ok. Rock solid OCXO, generate levels, audio... Only this RF power offset !!!In [ BLUE ] [ CONFIG ], all RF offsets are at 0 dB.Have anyone ever seen a such behavior ?One thing sure: HP engineers had real fun designing a radio comm test set able to display over 1 megawatt !!!!73 de Normand VE2UM

author: coppercone2
author_rank: Super Contributor
timestamp: January 15, 2024, 09:53:30 pm
content: it might be making 1MW of power

author: TheSteve
author_rank: Unknown
timestamp: January 16, 2024, 02:04:03 am
content: I've never looked into how it measures power but could it be switching to another range(that clearly has an issue of some sort).
Elejoy solar panel multimeter - Page 1
Forum section: electronics / testgear

author: shakalnokturn
author_rank: Super Contributor
timestamp: January 14, 2024, 03:11:11 pm
content: I stumbled across these PV MPP testers for 60-80€ on AliExpress, haven't done much research on them yet...They're said to be able to test up to 1.6kW, I'm curious to how they'd go about that in a handheld device. I'm assuming they find MPP in a very short time and user has to wait for the device to cool between measurements.
HP8510C owners , OS will not boot - Page 1
Forum section: electronics / testgear

author: shutchman2
author_rank: Newbie
timestamp: January 13, 2024, 05:24:26 pm
content: The 8510C has worked for years and all of a sudden, a week ago it stopped working. The self tests pass ( no error codes on the red 8-4-2-1 bit display on the front of 85101 ) and it gets to the "system initializing" message and does not go any further. After a while, the screen turns solid blue. (it thinks it's related to Microsoft?) The CR2477 battery on the I/O board was at 2.7V. I replaced it with CR2032, and it is now at 3.1V. I have another HP8510C that is working, which has OS HP8510C.06.30 Jul22 1991 OS. I used the Service Functions menu Disc command 21 (initialize disc) and then command 20 to make a copy of it's OS. I tried loading this disk on the broken HP8510C using disk command 19. This did not fix the OS boot problem. I have heard that the EPROM sometimes goes bad over time. The EPROM is AM27C020-200DC with 85101-80133 Rev 3.04. I do not have any original OS disks for either 8510C. I do not know what the OS version was on the now broken 8510C. Does anyone have any advice for me on what I could try next? Thanks in advance. Does someone have the Jedec file and checksum for this version EPROM chip?Regards, Hutch

author: KE5FX
author_rank: Super Contributor
timestamp: January 13, 2024, 06:22:43 pm
content: It looks like the 3.04 EPROM image is available onko4bb.com-- give that a try?

author: shutchman2
author_rank: Newbie
timestamp: January 14, 2024, 04:03:54 am
content: Thank You, I will give that a try. I have a Data-io Unisite.
Twintex PPM-5H07 500V 0.7A DC power supply LINEAR multi stage teardown - Page 1
Forum section: electronics / testgear

author: oz2cpu
author_rank: Frequent Contributor
timestamp: January 13, 2024, 03:54:06 pm
content: I did not expect to see a new cool methode of making a LINEAR dc powersupply,no relays, no pre-regulator, just linear outputstages in series, the idea is all unused stages deliver 0Vone diode loss pr stage is all you drop,it is a 500V unit so this makes sense, its performance is nice and stable, and quite high efficiency for a linear type,see all technical details here :https://youtu.be/BMRDwr5-sl4I am not afiliated with twintex, i just scored one that is all.

author: coromonadalix
author_rank: Super Contributor
timestamp: January 14, 2024, 04:18:35 am
content: until you have a full schematic it's pure speculation, you need a full teardown to see more of the pcb'syou may have other things at work here without knowing itand seeing how they "red wires" the power transistor onto the main board is a joke ... they should be beefier, and they should not show the core like this, poorly madeand yes you may assume and could be right, serial pass transistor in "serial" circuit to get to a high voltage, they use this for a long time in voltage calibrators, to get up to a 1kvthats why you need beefier pass transistor, because they will share the same maximum current load, and the voltage thru them add's up, but we need to know how they switch theses pass transistors ...this is an example of a Fluke 343A calibratorno pun intended ...

author: oz2cpu
author_rank: Frequent Contributor
timestamp: January 14, 2024, 10:00:47 pm
content: I think the schematic you posted use analog mode ?that means all series transistors share the same voltage drop ?I also own a fluke 343A i think i recall it is 1100V at 25mA = 27 watt outputyou have also seen the range switch and first voltage dial handle input voltage to serie regulator,so the voltage drop is not too high, when only low voltage out is needed, quite smart.what I claim this Twintex does :they have one set of transistors made by a double pair, for better power handelingthey are the only ones in analog mode = handle the voltage regulation.all other transistors are on/ off only, and in series, with their own bridge rectifier, also shown quite well in the video,and when in off that stage is skipped by a reverse diode,and when on, it simply add 100V to the input side, of the linear series regulator set.quite smart way to avoid relay switching, so they use transistor stage switching,sorry i dont have a schematic, hope one is leaked one day ??
Rigol MSO5000 Arb Generator DC offsets - Page 1
Forum section: electronics / testgear

author: MotoDan
author_rank: Contributor
timestamp: January 15, 2024, 06:46:20 am
content: I was trying to setup my 5000 to output a simple 0-5V square wave today and was surprised to find that I couldn’t add the required DC offset. Apparently Rigol thinks everyone wants a bi-polar output. With the level set to 5v (the max) I couldn’t change the DC offset at all. I ended up having to set the level at 3V with a 1.5V offset in order to produce a 0-3V signal. I hope I’m overlooking something. All of my other arb gens can do a 0-5V output without any trouble.
Toptes CT-300 (carbon monoxide detector) - Page 1
Forum section: electronics / testgear

author: nikitasius
author_rank: Regular Contributor
timestamp: January 13, 2024, 11:00:45 pm
content: Hi folks!I was burning some gas in my Soto Hinoto candles or sometimes cooking on gas & also i have "chauffage au gaz", mean my appt heating by gas when i enable it (or automatically).The heating device was repaired, cause it had CO leak and remember that i had painful head in past days (regarding the docs it's 35ppm CO). So.. im planning to do some camping, heatingm enjoying fire and i don't wanna die + also i have friends whos on 100% on gas so.. i can check if they have no excessive CO.I was googling and found Toptes CT300 on.. Amazon Francehttps://www.amazon.fr/dp/B0CL9MV4MG. Sadly their website doesn't mention this model..https://www.toptestools.com/so i goodles a bit more, found some aliexpress stuff on another brand which aren't available in France.. well, checked reviews, found only this videoNo tech reviews, no any useful stuff. On amazon.fr all reviews was from "vine club" or testers who got it for free.. so you know how it's goin.. so i decided "well i have amazon prime, if this bitch doesn't work i will return it". Paid my 36.99€ got it today and.. it works lol.1st we need to know that these sensors doesn't detect only CO, it detect other gas also and these gases affect final ppm indications. One more, one less. So be sure that there are no other leaks or your CO values will be bit wrong..Here is a google docs folder w/ all media stuff i did:https://drive.google.com/drive/folders/18UygvaP1QsapLhlqkg7EAvis4L2DkBJoThere are sensor photos:* PXL_20240113_190452921.PORTRAIT.ORIGINAL.jpg* PXL_20240113_222744816.jpgIt's japanese Figaro TGS 5141https://www.figarosensor.com/product/feature/tgs5141.htmlmy datamatrix have `2245230525230412771295042129`.Inside you will see device photos, serial number `H12D-L029493`.Also videos:* burning matches (no sulfur) in glass container PXL_20240113_195449085.TS.mp4* CO and other gases leaving container so ppm goes down PXL_20240113_195617063.TS.mp4* burning matches w/ sulfur PXL_20240113_195900521.TS.mp4Also i have new euro car (ford puma 2), so just after starting engine when there are smoke & smell:* PXL_20240113_211711982.jpg* PXL_20240113_211713597.jpgSo it catches well CO looks like.I'm not genius in PCB, but regarding the photos sensor + audio was soldered after manually and there are tiny traces of flux. Also it use SoC w/ 24bit ADC SDIC 8709https://www.sdicmicro.cn/en/product/detail/id/10432.htmlI will attach some photos here but for more photos look gdrive.Negative moments: ecran is "always on" when device is on.Regarding the PCB there are places for other chips, also missing "vibro" & "NTC" (idk what is NTC).PCB version is `HT621_V1.2`