hybridfree/eevblog-posts huggingface dataset:
Ono Sokki CF-350 Instruction Manual - Page 1
Forum section: electronics / testgear

author: Clueless
author_rank: Contributor
timestamp: February 05, 2023, 11:43:57 pm
content: I have a good quality printed copy of the CF-350 user manual. If someone has this analyzer but no manual, I would be happy to send this for the cost of postage. And maybe a cup of coffee. There is a lot to the manual. Looks like about 1.5" of paper, printed double-sided. I used to have one of these analyzers and found the manual to be extremely helpful in learning how to use it. But sadly I didn't have the service manual, so when the analyzer stopped working that was the end.
Transform noisy bench power supply to silent one - Page 1
Forum section: electronics / testgear

author: r6502
author_rank: Regular Contributor
timestamp: February 05, 2023, 11:55:02 pm
content: Hello all,I could get an EA bench power supply 2x16V max 5A + 5V supply for a good price (PS 2316-050, the main 2 outputs could be run independent, parallel or in serial). The annoying thing with this device is, that it perfprms like a vacuum cleaner when turned on. The fans for cooling the power electronic, are running at full speed when turned on.I had to improove this, so that the fans are running at high speed only, when a lot of power drawn from the external loads.My goal to minimize the noise of the PS was to use only stocked components for this weekend project. I do not wont to use µC or special IC's (like microchip specil fan control chips like the TC647 or similar). I used what I found in my stock.The design is based on a NE555 used as timing generator and an 74HC123, Dual retriggerable monostable multivibrator, to generate the the PWM for the fan and a few resitors / capacitors and an 100k NTC acting as sensor for the temperature of the heat sink.I think it is a really simple design - please have a look at the atacheed documents and leave your comments.Have a nice week - Guido

author: Clueless
author_rank: Contributor
timestamp: February 06, 2023, 12:35:47 am
content: I had a 80x80mm PC case fan with temperature sensing speed control circuitry built in. The speed is based on the temperature sensed by a thermistor attached with ~6" leads. This was the perfect solution for me to quiet down an HP triple output supply. It looks like the same might work well for your application, if they are still available and if the maximum flow rate is high enough. Sorry that I don't remember the details on the brand of the fan or where I purchased it.

author: dobsonr741
author_rank: Frequent Contributor
timestamp: February 06, 2023, 01:09:49 am
content: I would not build it, rather buy. This guy did the same /w CN made small fan PWM controller:https://blog.donbowman.ca/2018/12/15/project-solitude-silence-the-power-supply/

author: ledtester
author_rank: Super Contributor
timestamp: February 06, 2023, 02:14:52 am
content: I found this blog post on adding a fan to the Topward 6603A helpful:http://www.kerrywong.com/2012/12/08/adding-a-fan-controller-to-topward-6603a/It's as simple comparator circuit which only turns on the fans when the main heatsink reaches a certain temp.I think the main challenge is securing the temperature sensor to the heatsink. In the blog post a tape (perhaps with thermal adhesive) is used. I'd consider tapping a hole for a screw.
Tektronix SD-24 dual channel TDR/sampling head - Page 1
Forum section: electronics / testgear

author: bozidarms
author_rank: Regular Contributor
timestamp: February 05, 2023, 02:45:47 pm
content: For some time i was on looking for one SD-24 head, and finally i got one.That was mine third one, but this time a real winner!All measurements are far better than stated - i presented some here.In the case of such old devices, it is necessary to test them beforehand and sometimes you will be rewarded with real gems.Good measurements values may also be correlated with relatively newer CSA830A, mine has a little bit over 1000 working hours.
I have 120W ASUS PSU, which Buck-boost controller is better DPS3003 or 3005? - Page 1
Forum section: electronics / testgear

author: jkp389
author_rank: Newbie
timestamp: February 05, 2023, 01:58:21 pm
content: So my basic math shows that I should go with the 30v 3a module, which gets up to 96W giving enough space for the PSU to breathe. But then, I see a lot of builds where the PSU is weaker than the module. I am willing to invest a bit more in a DPS3005 or DPH3205 as I want to use it as a hobby bench power supply, but they are rated at 150 and 164W output accordingly. Can they overload the PSU if I don't check the numbers all the time?

author: wraper
author_rank: Unknown
timestamp: February 05, 2023, 02:31:54 pm
content: Unless you can limit maximum current in settings, I do not recommend using a more powerful module since it opens possibility of overloading the PSU. Also I don't see a point buying buck-boost variant as it's almost in a price range of Gophert NPS-3203 and NPS-1601 and you get a finished product, not something you need to slap together.
Budget Power supply with Ethernet (LXI/SCPI) - Page 1
Forum section: electronics / testgear

author: nightfire
author_rank: Frequent Contributor
timestamp: February 04, 2023, 10:15:42 am
content: I am currently thinking of having an addition to my wishlist for nice testgear. As my scope and electronic load are capable of being controlled remotely, I would like to extend that to a power supply.Requirements: 0-15V, 2A, being able to setup voltage in 0.1V steps, and 10mA current limit.Does not have to be able to present a cool display etc., remote controllability is the key feature here.Any suggestions for some budget models, that do not break the bank?

author: tautech
author_rank: Super Contributor
timestamp: February 04, 2023, 10:24:25 am
content: Quote from: nightfire on February 04, 2023, 10:15:42 amAre we telepathic ?Anyways, SPD1168X and SPD1305X both meet your requirements.
Hantek DSO2D10 UART decoding not working - Page 1
Forum section: electronics / testgear

author: Nilo
author_rank: Newbie
timestamp: February 04, 2023, 04:23:56 pm
content: Hi!I was just trying out UART decoding on my Hantek DSO2D10 and noticed it wont decode, just saying "Please adjust the trigger(No trigger)".I read the manual and looked up the sections for UART decoding and triggering to set it up right, yet the scope wont decode anything.I have the CH1 connected to USB/UART converter, baud is 4800, 8 bits, 1 stop bit.Am I missing something?My Hanteks firmware is version 3204.

author: DavidAlfa
author_rank: Super Contributor
timestamp: February 05, 2023, 01:41:39 am
content: You're probably on FW3204, it's a known issue.Try FW3202 or 3205, check the FAQ in my signature.
Low cost power meter - Page 1
Forum section: electronics / testgear

author: pope
author_rank: Frequent Contributor
timestamp: February 04, 2023, 11:11:35 am
content: I would like to get a low cost power meter. Nothing too fancy but it should be able to measure accurately low power devices (say anything above 100mA).After a bit of research I found theZHURUI LPT200and theZhurui Power Recorder PR10.Do you know if these are any good/accurate for low power devices?Also, I'm open to other recommendations of course!Thanks
Agilent 8560E SA troubleshooting guidance - Page 1
Forum section: electronics / testgear

author: NHnewbie
author_rank: Contributor
timestamp: February 02, 2023, 07:56:59 pm
content: All,Looking for troubleshooting guidance on my Agilent 8560E SA. I have owned this SA for several years and it has worked well. Recently I am seeing an issue that requires attention. The SA boots up with a clear crisp trace and graticule. When the CAL signal is connected to the input, I see the expected pattern on the screen. The problem is that most screen annotations and menus are not displayed. I can bring up some menu items by pressing keys on the front panel, however most of the usual text does not appear. Also no error messages. I have opened up the unit to inspect the A2 controller board (seems like the most likely location of the problem) and see no obvious issues.Any guidance appreciated.RickK8EZB
It's possible to unlock MSO2202A on 2023? - Page 1
Forum section: electronics / testgear

author: Hugorp
author_rank: Newbie
timestamp: February 02, 2023, 11:56:58 am
content: Hi all,I have a Rigol MSO2202A without serial decode options activated. I was trying to unlock it using Rigol bildschirmkopie by LAN and i gel the memory dump file xxxxx.scpiI used rigup 0.4 and rigup 0.4.2 with the memory dump file. Version 0.4.2 shows error "no keys" but version 0.4 gave me RC5KEY1, RC5KEY2, XXTEAKEY, PUBKEY, PRIVKEY and SERIAL.So i used the app in gotroot.ca/rigol/riglols with serial number, private key and DSHH option but the key given didn't work in the MSO2202A.It's possible to unlock it?Software version is: 00.03.06Hardware version is: 2.3

author: tv84
author_rank: Super Contributor
timestamp: February 02, 2023, 02:43:31 pm
content: I bet that in 2024 it will still be possible. You must use rigup to finish the job, not just extract the keys.
Any product similar to Fluke SV225 'Stray Voltage Adapter' ? - Page 1
Forum section: electronics / testgear

author: TomKatt
author_rank: Frequent Contributor
timestamp: February 07, 2023, 12:05:46 pm
content: I'm somewhat embarrassed to admit that despite believing I have a pretty good knowledge of electronics, I was recently stumped while testing some home mains wiring in a 2 way switch circuit... With the circuit breaker off, I was still picking up rather substantial voltage readings that I now understand to be 'ghost voltages' induced into the wiring by other live wires nearby the ones I was testing. My Greenlee DM820A (Brymen BM827S?) does not have a LoZ feature - something I now better appreciate and believe should add to the toolbox!Rather than purchase another meter to obtain LoZ capability, I see that Fluke makes an SV225 'Stray Voltage Adapter' that is a small plastic cased adapter with standard width banana jacks that adds LoZ input to any meter with standard jack spacing. 'Electronics Projects' has a YT video repairing the Fluke SV225, and it's apparently a VERY simple circuit consisting of a 3K resistor with a PTC on each leg that adds a parallel resistance to the meter input to drag any induced voltage down to 0. However, Fluke charges $99 for this simple adapter (which probably has a $10 BOM). I can appreciate the safety factor and whatnot, but $99 seems a bit excessive. I could build my own adapter, but without knowing the exact parts used would rather not guess and bet with my life should something catastrophic occur.Does anyone know of a similar product that might be a bit more economical ?Thanks!YT video of Fluke SV225:
lecroy 422 bad sector damage HDD - Page 1
Forum section: electronics / testgear

author: bengata
author_rank: Contributor
timestamp: February 01, 2023, 03:09:02 pm
content: Hello ,I am looking for XStreamDSOInstaller4.6.1.5.exe. Or a new version. The reason is that the HDD was damaged after an electric shock and I cannot restore anything from it. Please give a link if you have one. The manufacturer denied me registration and I can't download from there

author: Momchilo
author_rank: Regular Contributor
timestamp: February 01, 2023, 03:31:56 pm
content: Hi,did you save the calibration folder? This would be quite important. Otherwise the scope will probably be out of specification.I don't need to register and can download the software without any issues from the Lecroy website. I uploaded X-Stream 6.8.1.4 for you. That is the newest possible version for the 4XX Wavesurfer series. Here you can download the X-Stream.exe:https://www.file-upload.net/download-15087198/xstreamdsoinstaller_6.8.1.4.zip.html

author: bengata
author_rank: Contributor
timestamp: February 01, 2023, 03:49:49 pm
content: The bad thing is that I can't access anything from the old HDD. I don't have a calibration folder saved . Thanks a lot for the link but i can't download

author: Momchilo
author_rank: Regular Contributor
timestamp: February 01, 2023, 03:58:33 pm
content: They deleted the file. I uploaded it again as a zip-file. Here you go:https://www.file-upload.net/download-15087198/xstreamdsoinstaller_6.8.1.4.zip.htmlI can't upload it here in the forum because the file is too large.

author: bengata
author_rank: Contributor
timestamp: February 01, 2023, 04:00:26 pm
content: Thanks, I took it down
(HP 8562A) Preselector Offset/Slope, Flatness filter diagram or visual? - Page 1
Forum section: electronics / testgear

author: Kal_Ebration
author_rank: Newbie
timestamp: February 02, 2023, 03:51:21 am
content: I have been calibrating SA's for over a year now by following the guide but I'm curious to know what the filters look like and how they are responding to values. I tried searching for a bit and maybe I'm just not using the right terminology to find said visuals.Any help or pointing in the right direction is much appreciated!Thanks!
Protek 6510 Oscilloscope User and Service manuals - Page 1
Forum section: electronics / testgear

author: EvgenyG
author_rank: Regular Contributor
timestamp: February 01, 2023, 03:31:04 am
content: Hi All,Does anybody have a user and/or service manual for Protek 6510 Oscilloscope? Also known as Hung Chung 6510 - 100Mhz Oscilloscope.It is a pretty nice old school analog scope. Had a fat trace fault that I've managed to fix. Would love to calibrate it now.I've searched the Internet but I could only find user/service manuals for 6502/04/06 scopes but those are completely different inside, both horizontal and vertical units.
first impressions of a 12 year old (?) meter - Page 1
Forum section: electronics / testgear

author: golftango
author_rank: Contributor
timestamp: January 31, 2023, 08:04:46 pm
content: i have no need for such a meter since although i'm a 55 year ham and been tech-adjacent my whole life i'm now outsourced and retired and i can no longer see good enough to work on modern circuits with their tiny components. but i'm still studying and experimenting and my electricity in this crap house justifies having test equipment for that at least.in any case, i hadn't bought a new meter in decades and still use simpson and triplett analog voms so when i saw a very futuristic one on amazon with a color screen and an intriguing /auto/ mode i bought it (kaiweets km601) and got sucked down the rabbit hole.i want to claim in advance i've beta tested my whole life and i tend to find the negative things and bugs before i get to the positive things.i had settled on the 87v max before i came across a 28-ii on ebay and came to realize that there were only minor difference. i got the 28-ii in yesterday (in nearly like new condition with box & accessories for $200-250 less than a new 28ii or 87v max) and first impression was not positive as i wanted to replace whatever batteries were in there with duracells and found the battery compartment door an infuriating design. one spring is in the compartment and two springs are on the inside of the door and i'm still not sure i got it to fit together properly as the seams aren't flush although the gasket inside seems fine. needless to say, not at all impressed with this design which i've seen in none of the hundreds of battery-powered devices i've bought over the years.anyway, my next big huge disappointment was to find that two of the features i was looking forward to the most which are toggled on with a power on sequence are not persistent. what genius determined that? if i take the trouble to turn them on then i want them on--i don't want to have to turn them on every single time i power on the meter. the smoothing and the higher resolution are the ones i'm talking about, but indeed it doesn't look like any of them are persistent except the ºF/C setting so they at least understand the concept. perhaps i'm missing something, but the manual is very detailed and thorough and i'm sure would have mentioned it.on the positive side, i suspect the neighbors kids could use this thing for soccer practice--it's a beast! by far the most impressive piece of test equipment i've owned. oh, and despite it being bought used and iffy origins judging by the documentation and batteries, it registered fine at fluke. also, i called them to ask some questions and quickly got a very friendly english-speaking technician and we chatted so long i managed to find my answers before he got around to looking them up. very impressed./guy (73 de kg5gt | wqpz784)
Riden - alternarive PC software - Page 1
Forum section: electronics / testgear

author: scarman20
author_rank: Newbie
timestamp: January 31, 2023, 09:44:50 am
content: Hello everyone, this is my first post, so first I'd like to say hello to everyone. I have a question about Riden service power supplies. Is there any alternative PC software for these devices? The one provided by the manufacturer sucks. Ideally, it would be a program that shows the same screen on the computer as it is on the device display, without a thousand additional functions that badly affect the readability of the application. I think that creating such an application would not be a big problem, there is, for example, the PX100 battery charging program that fully works with Riden devices.I found something on GitHub but I don't know how to run it on Windows:https://github.com/ShayBox/RidenGUIThanks in advance for the tips. Regards

author: tatel
author_rank: Frequent Contributor
timestamp: January 31, 2023, 09:54:23 pm
content: https://www.eevblog.com/forum/testgear/ruideng-riden-rd6006-dc-power-supply/
Itech IT8512G+ DC Load strange behavior! Is this normal? - Page 1
Forum section: electronics / testgear

author: Faranight
author_rank: Unknown
timestamp: February 01, 2023, 06:05:10 pm
content: Greetings, EEVBlog!So I recently got anItech IT8512G+DC load that I planned to use for some PSU and solar testing. I've been messing around with this unit on some small solar panels, and I noticed that the constant voltage (CV) option causes the voltage to crash under certain circumstances. I wasn't able to pinpoint the exact conditions on a solar panel, but I decided to reproduce the issue with a lab PSU @10VDCand a470Ωresistor in series. At some point the unit will not be able to accurately regulate the voltage any more (there will be a voltage offset) under the CV load option until the voltage is sufficiently reduced. I'm not sure what's going on here or whether this is normal behavior or not, but I want some opinions before I go pestering the ITECH tech support.Is this a bug in the model or am I doing something wrong?It sort of acts like a schmitt trigger... crashes at high voltage, but recovers at low voltage. The thresholds are not constant and seem to be dependent on the source voltage and the resistor value.Here's a short video for better demonstrationKind regards!EDIT: Changed video host to Vimeo.

author: HKJ
author_rank: Super Contributor
timestamp: February 01, 2023, 07:07:20 pm
content: Quote from: Faranight on February 01, 2023, 06:05:10 pmI have not checked your links, but if the current is within a few mA of what is needed for the correct voltage, you will not get better.The load adjust current and have a resolution of about 1mA, i.e. it cannot do smaller steps to adjust to correct voltage.

author: Faranight
author_rank: Unknown
timestamp: February 02, 2023, 08:29:29 am
content: Hmm, the odysee link doesn't seem to be working for me right now. I'll see, if I can upload it to vimeo later.You think so? Here are the IT8512G+ specs from the datasheet.I'm assuming the device switched to the lower measurement range (left column) since I did hear a relay click after lowering the current range down to 1A.This range seems to have the resolution of 1mV in CV mode and 0.1mA in CC mode, respectively.
Frequency response analysis with Owon vds1022(i) - Page 1
Forum section: electronics / testgear

author: jasonRF
author_rank: Regular Contributor
timestamp: January 29, 2023, 10:18:20 pm
content: Attached is some python code for generating Bode plots with the vds1022(i) using the SCPI interface. I have only used the code in python 3.9 running under Windows 10. Since I have no intention of making it nicer I thought I may as well share it as-is. Warning: I am not a good programmer, so don't expect great code. If you improve it, or have a better approach, please share!The main script is vds1022autoFRAv0.py, which includes a lot of comments to explain how to use it properly. But if something is confusing please ask. It allows the user to select from 3 different signal sources:1. PC audio (such as the headphone jack) which of course only works for audio frequencies. If you use this approach, please read and heed the warning in the comments.2. An Arduino-controlled AD9833-based signal generator I posted herehttps://www.eevblog.com/forum/projects/simple-2-mhz-sine-generator-python-bode-plotting-script-for-picoscope-2204a/msg4501558/#msg4501558It is usable from about 1 Hz to 5 MHz3. tinySA spectrum analyzer, which can be used as a sinewave source. It is most useful at frequencies of 100 kHz and aboveThe remaining four .py files include the interfaces for the scope and the signal sources. Hopefully, reading the FRA script should provide enough examples to understand how to use them.Attached are the output plots for testing two different devices, as well as a couple of plots comparing the results to what I get with a Picsocope 5244B and the FRA4Picoscope software:A. simple low-pass filter consisting of a 680 Ohm resistor and a 100 nF capacitor. The phase rising above 100 kHz is consistent with the presence of a non-zero capacitor ESR (or perhaps resistance in solderless breadboard, etc). I don't know why there is a discrepancy in the phase between the 5244B and the vds1022 using the arduino/AD9833 generator; it could be because it does not use the same solderless breadboard setup for the filter, or perhaps is an SNR issue (the 5244B has better sensitivity than the vds1022). EDIT: and now that I think about it, I think I haven't calibrated the probes for either in awhile ...B. discrete battery-powered headphone amplifier, built before I had any kind of scope so did not realize it had such a large bandwidth. It is driving a 33-Ohm resistive load here.Hopefully other folks find this useful.jasonEDIT: by the way, I actually have the Multicomp Pro MP720016, which is a rebranded vds1022.
Teardown of an appliance tester BBC Metrawatt Metratester 3 - Page 1
Forum section: electronics / testgear

author: WackyGerman
author_rank: Regular Contributor
timestamp: July 20, 2014, 07:05:15 pm
content: Here are some pictures of my teardown of the BBC Metratester 3 appliance tester . On the pictures you can see the multiple board construction of this unit . What a hell if you have to repair it.

author: SeanB
author_rank: Super Contributor
timestamp: July 20, 2014, 07:15:25 pm
content: Lovely power devices in there, have not seen those cans for a long time.

author: WackyGerman
author_rank: Regular Contributor
timestamp: July 20, 2014, 07:26:57 pm
content: yes old stuff from the 1970`s . This good old puppy still works . The measuring voltage for the isolation test ist still roundabout 740 VDC and the scale shows the value of 10 MOhms when testing the voltage with a digital multimeter

author: de.boer
author_rank: Newbie
timestamp: January 28, 2023, 05:29:26 pm
content: Hallo WackyGerman,ich las im Forum Du bist ein Besitzer eines BBC Metrawatt Metratester-3.Auch ich habe solch ein Gerät.Leider ist bei meinem der Printtransformator defekt und ich kann kein Originaltrafo mehr zur Reparatur auftreiben.Mein Plan ist eine Reparatur mit mehreren Standard-Transformatoren.Dafür müsste ich die Ausgansspannungen kennen.Ich hätte eine Bitte:Würdest Du bitte für mich an Deinem Gerät ausmessen welche Sekundärspannungen der Trafo hat?Da gibt es drei Sekundarwicklungen, eine mit einer Anzapfung - also benötige ich die vier AC-Spannungswerte.Auch bei der Primärwicklung gibt es drei Anschlüsse - einer ist unterbrochen. :-(Hast Du eine Idee wofür der dritte Primäranschluss ist?VG van de.boer
Rohde & Schwarz quoting 3 months lead time on new equipment purchases ?! - Page 1
Forum section: electronics / testgear

author: luudee
author_rank: Frequent Contributor
timestamp: January 27, 2023, 04:19:05 am
content: Hi Guys,just tried to place an order for a NGP804, and was told there is a 3+ months lead time.Anybody else encountered that ?Thanks !luudee

author: tautech
author_rank: Super Contributor
timestamp: January 27, 2023, 04:31:13 am
content: Quote from: luudee on January 27, 2023, 04:19:05 am6+ weeks for some products has been normal for a couple of years with component shortages and shipping delays.Then add another 6+ weeks to get things a few 1000km and things really start adding up.FedEx and DHL are just loving it.

author: pdenisowski
author_rank: Super Contributor
timestamp: January 27, 2023, 05:23:32 pm
content: Lead times on R&S products vary based on the product, options, promotions etc. It's definitely not 3 months for all productsI don't have visibility into lead times for Thailand (?), but I do know we have a worldwide promotion on power supplies (including an NGP package) going on right now.https://www.rohde-schwarz.com/us/products/test-and-measurement/power-supplies/power-supplies-promotion_253924.html

author: Sighound36
author_rank: Frequent Contributor
timestamp: January 27, 2023, 07:35:39 pm
content: Lecroy is pretty much the same supply time, waiting for a new WaveproHD lead time is cited at 18Weeks same for the Waverunner HD and HDO6000B as well. Usual chip supply issues

author: Martin72
author_rank: Super Contributor
timestamp: January 27, 2023, 10:20:33 pm
content: When we bought our two Lecroy scopes in 2019, we had to wait 3 months for them because the units are assembled in the U.S. only when ordered and are not in stock.The chip crisis has probably made the wait time worse, no question.

author: luudee
author_rank: Frequent Contributor
timestamp: January 28, 2023, 04:37:28 am
content: Yeah, I understand that there is (was) a component shortage. But it seems many large manufacturers have their own stock ...Siglent and ITECH don't appear to have this kind of issues. I am told the ITECH IT-N6952 is in stock for example.This is NOT a high-end DSO, it's a fancy power supply. So it really is strange IMHO ...(Shipping to Thailand is usually quick. But we have to add a week for customs. Sometimes only a day, sometimes 4 days .... )Cheers,luudee
DECTECH DC load calibration software. - Page 1
Forum section: electronics / testgear

author: f14
author_rank: Regular Contributor
timestamp: January 25, 2023, 10:37:33 am
content: Hi Guy,I need calibration some Dectech 8312D load and in the website they told use software calib not hardware via pot inside the load like chroma( and yes no pot inside dectech load ). I tried sent a email to Dectech but no response . Hope someone in here have it . this load usual use in ATE systemhttp://www.dectech.cn/productinfo/110997.htmlthank you for your help!
Re: Keithley 2015 THD - question - Page 1
Forum section: electronics / testgear

author: mzacharias
author_rank: Frequent Contributor
timestamp: January 24, 2023, 10:28:30 pm
content: I have a quick question regarding a Keithley 2015 THD multimeter. (Yes I know there's much better analyzers around, but I have neither the money nor bench space for those.)As I recall, the loop-back distortion runs about .05%, (haven't tested lately) yet units under test routinely measure .005%, often even less, still using the internal generator.Just wondering why this would be. BTW the 2015 owners manual specs .005.

author: switchabl
author_rank: Frequent Contributor
timestamp: January 24, 2023, 11:52:46 pm
content: 1. If the DUT acts as a low-pass filter, it may suppress higher harmonics present in the test signal. E.g. if you are testing an audio amplifier with a bandwidth of 20 kHz at 10 kHz, anything above the 2nd harmonic will essentially be cut off, while in loop-back configuration the full 50 kHz bandwidth of the analyzer is available. Look at the individual harmonics instead of THD to see which ones are affected.2. Unlike noise, distortion components add coherently. If they are out of phase, the DUT distortion can cancel out some of the distortion of the generator (or analyzer) instead of adding to it. This introduces serious measurement uncertainty as you get close to residual distortion level of your instrument. You want your generator and analyzer to have significantly lower distortion than your DUT to avoid this.(Also, the distortion level of the generator will be somewhat dependent on the load. However, I doubt it will become significantlybetterwith a low input impedance DUT connected compared to loop-back.)
Calibrating frequency counter SDS1102CML (non+)  - Page 1
Forum section: electronics / testgear

author: dxhound
author_rank: Newbie
timestamp: January 25, 2023, 08:54:11 pm
content: I bought a SDS 1102CML and upgraded it to the latest firmware and to an SDS1152CML. The last thing that I want to do is get the the 6 digit frequency counter calibrated. I checked it agaisnt my 10mhz rubidium standard and the counter on the scope reads 9.99998. Im sure the IF frequency used for the self cal process is the 1kz square wave. on my HP53181a frequency counter, the 1kz square wave is off showing 1,000,069.1) is there a way to calibrate the counter or the 1khz IF?2) Is it possible to hack the counter to display 7 or 8 digits?

author: dxhound
author_rank: Newbie
timestamp: January 26, 2023, 10:16:12 pm
content: ??

author: tautech
author_rank: Super Contributor
timestamp: January 26, 2023, 10:27:30 pm
content: Just know yours is 2 Hz off at 10 MHz.If you can imagine the counter and probe cal are referenced to internal clock/s with their own specific accuracy and jitter so therefore to have a cheap device be precisely accurate is unreasonable.The probe Cal output is a reference fast edge square wave NOT a frequency standard however for it to be just 0.069 Hz off is impressive.Can you by engaging a frequency measurement get the better resolution you seek ?

author: dxhound
author_rank: Newbie
timestamp: January 26, 2023, 11:07:41 pm
content: Alot of work I do with transceivers require to not only to calibrate the frequency, in the different IF stages, but to also adjust the waveform for spectral purity. My hope was to do this all on one device and declutter the already crowded bench.I know 200hz off does not sound like much, but when dealing with SSB where there is no carrier to reference, this will creat an issue, especially on CW signals where the tx signal may only be 50hz wide.

author: dxhound
author_rank: Newbie
timestamp: January 26, 2023, 11:08:52 pm
content: I would add, that the 1kz out and frequency counter seem to be very stable, just off....
Tek DPO3054 stuck in endless video test loop - Page 1
Forum section: electronics / testgear

author: pets57
author_rank: Newbie
timestamp: January 24, 2023, 10:52:28 am
content: Hi all,My Tek DPO3054 is stuck in a continuous, unstoppable video test mode. It cycles full-screen splash colours every 15s or so then briefly returns to the post boot 'power-up self test passed' screen with push menu off, etc. Nothing seems to stop it!This occurred after running an SPC which passed fine. However, after that I noticed the Error Log screen contained a whole bunch of low-level 'Manufacture Test' options one of which was 'Run RTC OK'. Inadvertently I pressed this and now it continually cycles this damn video test loop!!Nothing stops it - cycling power, re-installing firmware, etc.Help and thanks in advance!!PeteSTOP PRESS - Ive sorted this - solution below.The firmware version v2.14 for the DPO3054 contains a 'manufacture test mode, accessed by pressing the 3rd then 4th side buttons when in the Error Log screen. This is useful when debugging an SPC fail (i.e. confirming that a recal will fix). However, when in this mode there are some buggy tests (or tests that should not be used without further system knowledge) as described in my original post above. This is not available in later firmware versions. Btw, I was first put onto this v2.14 feature by Tek support when trying to debug an SPC fail as it has a menu option for showing more error detail and erasing the error log.When stuck in this endless unstoppable video test loop there is a 2-3s gap every 15s or so when the normal scope screen and user controls are active. Patiently navigate to the Utility/Self Test/Self Test screen and select Abort Self Test - you will see this weird behaviour is actually a stuck in video test mode. Aborting this self test fixes the problem.Lesson learned - 'don't mess with low level diagnostic test modes without detailed knowledge'!Pete
Tenma 72-8695 - Page 1
Forum section: electronics / testgear

author: Geoffa
author_rank: Newbie
timestamp: January 23, 2023, 04:36:15 pm
content: Hi, Does anyone have a circuit giagram for Tenma 72-8695 with the PCB 20100521 ?Will be much appreciated to repair, seems to have lost voltage control feedback.- otherwise excellent PSU.I have done a search but not found.Thanks

author: mcinque
author_rank: Unknown
timestamp: January 23, 2023, 09:44:58 pm
content: Most probably you didn't find anything beacuse it's rebranded. Tenma does this with Uni-T products for example. Look at board inside if you can find numbers or codes and search them on google. You could find the original manufacturer.
Cat 5/6 cable testing with a scope and frequency counter?  - Page 1
Forum section: electronics / testgear

author: Zyvek
author_rank: Regular Contributor
timestamp: January 23, 2023, 06:38:26 pm
content: This is just under the "is it possible/just for fun" category. If I needed to do this in a regular basis, I'd buy a dedicated cable certification tester.I have a new box of older Cat 5 cable. My understanding of cat 5, 5e, 6, 6a classifications is largely based on the frequency they can support. (I believe Cat 5 being 100Mhz and Cat 6A being 500Mhz)Is it possible using a equipment that I have in my lab? (Scope, frequency counter, frequency generator)I'm guessing someone has tried this before.Thanks, sorry if this is a silly idea.

author: eloso
author_rank: Regular Contributor
timestamp: January 23, 2023, 06:56:38 pm
content: Well I happen to think its a great question - for academic and educational purposes only of course. In reality as you are obviously aware, a cable certifier is the "proper" way to do it.To certify a cable you need to measure its return loss and its crosstalk between the other pairs in the same jacket and compare this with the laid down standards. I reckon as a minimum you need a VNA. A scope and frequency generator isn't going to cut the mustard.The question sent me off on my own internet search and I thought this was quite a nice explanation which touches on an answer to the question.https://www.idealnetworks.net/wp-content/uploads/2019/04/Certification_why_what_how_US.pdfHas anyone ever bothered to attempt this ? It kind of begs the question - if you are a designer of cable certifiers might you use a standard lab VNA to establish baseline measurements to calibrate your LAN certifier design/prototypes against ?CheersEloso
Atorch DL24MP :  a flaw or a strange strategy? - Page 1
Forum section: electronics / testgear

author: Filippo52
author_rank: Regular Contributor
timestamp: January 22, 2023, 10:42:28 am
content: This is not a product review but just an observation about a strange thing.The DL24MP model, as anyone who owns it knows, uses 4 MOSFETs instead of one. Unfortunately there are small heat sinks and therefore the ability to disperse heat is not very good. However the MOSFETs share the work and the probability of burning even at startup when the heatsink is cold is much lower.To balance the load between the 4 MOSFETs Atorcho has adopted the solution of putting a low value resistance to level the inevitable differences between the mosfets as well as obviously driving the gates of the MOSFETs independently. On paper, an excellent performance. However, looking closely at the resistors, I noticed something very strange.On one side there are two resistors with the inscription 0R22 and on the other side with the inscription 0R25. The measurements, made with an LCR such as the DE5000, confirm that there are 0.22 ohm resistors on one side and 0.25 ohm resistors on the other.I thought of a strategy and then did some miduras under load. These measures confirmed the fear. By giving constant DC 4 Ampere, MOSFETs with 0.22 ohm resistances draw a little more 1 A and those with 0.25 ohm resistances a little less. Nothing serious but why??I can't think of anything good and I ask you.Seems to me either a mistake or worse I ran out of resistors by one value and they used the closest ones thinking no one would notice the difference. But if so, does the vaunted attention to quality disappear due to a trivial mistake or the lack of a component?I am attaching two photos to document, only one of the resistors on each side can be read very well but I think it is sufficient.

author: dougbert
author_rank: Contributor
timestamp: January 22, 2023, 11:38:06 pm
content: Consider that would be happening if the DL24MP was being supplied with 12 volts at a 4 amp setting: each MOSFET (and the resistor in series with it) is getting about 1 ampere at 12 volts, sothe total resistance is 12 ohms. Thus, the 0.03 ohm variation in per-MOSFET resistance is totally insignificant. At the lowest reasonable input voltage (I found that my unit handled 1.5 volts at 4 amps ok),each MOSFET would have a resistance of about 1.5 ohms, but since each one would be dissipating only 1.5 watts, so there is no way that a ~3% variation in current would harm them.I suspect that the resistors are needed only prevent a sudden spike of voltage from harming the MOSFETS when they are fully turned on.
OWON SPE Power Supply loud fan noise - Page 1
Forum section: electronics / testgear

author: Miha
author_rank: Contributor
timestamp: January 25, 2023, 10:42:41 am
content: I bought Power Supply OWON SPE3102.And it have loud fan noise.How can I configure or modify the product so that the fan turns on only when it really needs to be cooled.
change ps 613u pots - Page 1
Forum section: electronics / testgear

author: fxkl47BF
author_rank: Contributor
timestamp: January 21, 2023, 07:52:53 pm
content: i acquired a non-working ps 613u power supplytwo 2200uf caps had explodedi replaced them and it appears to be workingmy complaint is the voltage and current pots are very sensitiveit's near impossible to adjust them with any precisioni'm thinking to replace them with multi-turn potsis this a good idea or a waste of time

author: Swake
author_rank: Frequent Contributor
timestamp: January 22, 2023, 09:46:15 pm
content: Yes it is a good upgrade certainly for the voltage, somewhat less useful for the current.You can use a multiturn pot or add a second 'normal' pot that will handle the fine adjust (about 1/10 or 1/20 the resistance of the original pot).Which method is better for you is more a question of preference. The 2 pot solution is somewhat quicker but less elegant.
UNI-T UT61D genuine bodge diode - Page 1
Forum section: electronics / testgear

author: hozone
author_rank: Regular Contributor
timestamp: January 22, 2023, 07:14:10 pm
content: Hello,I've a UT61D with some AC reading problem, reading are lower then it should be. As example my main here in Italy it's something around 220V but this the meter reads 50V.Opening it I've seen a few components with some sign of corrosion, at least it seems to me that. So simply resoldering three components solves the problem. For this reason I think my problem should have been a cracked solder.But that's not the reason for this post.Here I just want to show you what I think it was a genuine bodge high speed switching diode.When I opened the multimeter, I've noticed that the R9 does not seems a resistor. Indeed desoldering it, turns out that over the resistor someone in the farm soldered a high speed switching diode. It's marked C3, and I think it's a 1SS226, maybe to protect something, but I've not investigated further.This is just to show you some image of the meter and that diode.~ Side note: Image taken before desoldering and soldering it back again ~~ Side note: date on picture is wrong, I've take those picture a few days ago... not 2018 ~
Tektronix TDS 7XX/6XX/5XX external reference input mod? - Page 1
Forum section: electronics / testgear

author: hvontres
author_rank: Contributor
timestamp: January 21, 2023, 09:00:05 pm
content: I was wondering if any has added a better frequency reference to their older Tek TDS series scopes. I have been playing around with OCXOs and my new to me HP5316a and it seems that the timebase on my 744a has a lot of jitter on it. I looked at the TDS520b schematics (thank you xdevs) and it seems that the 1Ghz clock is derived from a 25ppm crystal. I was wondering if anyone has added an external frequency reference or even just a more stable internal reference on their scope. I was thinking having a PLL that could synch up with a 5 or 10Mhz external clock would be a great way to improve the scope.

author: tchiwam
author_rank: Regular Contributor
timestamp: January 21, 2023, 10:06:29 pm
content: I generate a PPS to the rear trigger on my TDS694C, that's usually pretty good to keep things in check. Since all my instruments are tied to that PPS too.I am still interested by a scope with 3GHz BW and >10Gsps with en external 10MHz ref.
Rohde & Schwarz CTS series firmware / service manual requested - Page 1
Forum section: electronics / testgear

author: MindBender
author_rank: Regular Contributor
timestamp: May 05, 2021, 07:28:28 pm
content: Hi,I have recently acquired a piece of niche test Equipment. A Rohde & Schwarz CTS65 Digital Radio Tester for GSM and DECT. Yes, it was offered as defective, but it also was so cheap that I couldn't afford not to buy it.I seems to boot just fine, but after displaying the options installed, it briefly shows and error, followed by the application restarting itself:### System error in file '.\fsrc\\STU.c'condition 'FALSE violated!'I was unable to get a DOS prompt on the instrument itself, but I dumped the CF-Card contents and I found a log file (FATAL.ERR) there, containing:Wed May 5 00:42:20 2021V5.56 16.11.04#### System error in file '.\fsrc\\STU.c', line# 757 ####condition 'FALSE' violated!String: 'TIMEOUT_IN_STU_TASK in Task State WAIT_FOR_DOWNLOAD_OK'#### end of error protocol ####Going though the stings of the main application, CTS.EXE, searching for the name of the .bin file (LHPROG.BIN) next to it, produces sting 'Link handler program file not found.' in close proximity. I think the application is uploading LHPROG.BIN into one of the MCUs, and times out while waiting for this firmware to report after launch.Does anybody here have firmware for this instrument available, to rule out corruption of a very old CF-Card? Thanks a lot in advace!Cheers!

author: MindBender
author_rank: Regular Contributor
timestamp: May 06, 2021, 08:16:12 am
content: If anybody has a service manual on the Rohde & Schwarz CTS series, or the CTS65 specifically, I would be more than happy to obtain a copy of it.

author: xenonfire
author_rank: Newbie
timestamp: January 21, 2023, 12:22:33 pm
content: Hi MindBender.Still looking for help?I have the same R&S machine and access to some files on the hard drive.Did you find the file \CTD\BIN\LHPROG.BIN or some firmware?
HP3582A Audio spectrum analyser - Page 1
Forum section: electronics / testgear

author: cowasaki
author_rank: Frequent Contributor
timestamp: August 31, 2022, 08:00:20 pm
content: I have been looking for an audio spectrum analyser for 5 years. I eventually found one I could afford at a police auction of all places. It was advertised as untested BUT with a 90 day return warranty due to their inability to test the item so they were unable to list it as working. As it was a 250 miles round trip I went to collect it with a carry bag containing some leads and a signal generator. Unfortunately when I got there the device lights up with a stationary dot at the middle near the top of the screen and no text. No amount of button pressing and turning of controls brought it to life and they looked at my dejected face and offered me a refund. I had paid £400 for it so had to take it. Only then did I realise that it was a refund but I could keep the faulty item as they couldn't sell known faulty goods.So I walked away (rather staggered away these things weigh a ridiculously large amount!) with the device but it was not working.When I got home the dot isn't now appearing either although when you switch the power off you see a flash of the dot appearing.The device was VERY well packaged so no damage was caused on the way home.So here I am with a faulty HP 3582A which cost be nothing.I planned to have a look inside and clean all the contacts then check the power supply and caps. After that its a bit outside of my area of expertise. Anybody on here know their way round one of these? Anybody know someone in England that repairs them that doesn't charge silly money? There is somewhere in the US that charges $500 for a repair, service and recalibrate package. Something like that would really suit me. The device is in surprisingly good condition." alt="" class="bbc_img" />

author: Duce67us
author_rank: Contributor
timestamp: August 31, 2022, 09:22:27 pm
content: Hello,Maybe check out this older post and see if it helps.https://www.eevblog.com/forum/repair/hp-3582a-repair/msg2795148/#msg2795148

author: tospa
author_rank: Newbie
timestamp: January 21, 2023, 11:36:21 am
content: I´ll try my luck here.I recently got a HP3582a analyzer, but it came without any probe(s).My question is, can I use "any" probe (e.g. oscilloscope probe) for this machine or do I need to find one of the original HP 10001A probe(s) that was recommended by HP at the time?

author: cowasaki
author_rank: Frequent Contributor
timestamp: January 21, 2023, 12:06:13 pm
content: It is audio frequency so pretty much anything will give you a reasonable display. If the output you want to view is BNC just use a BNC to BNC lead. For looking at an audio test point I tend to use a BNC to micro clip lead or similar. I modified Kim with a couple of pairs of speaker output post with central 4mm sockets as the originals were damaged or missing. I have a couple of those leads that have a ground and hot pair of 4mm banana plugs 19mm apart then go to a lead with a crocodile clip and a micro clip.
Auto-Ranging circuit using op-amp - Page 1
Forum section: electronics / testgear

author: Anitech
author_rank: Newbie
timestamp: January 12, 2023, 08:11:53 am
content: I am trying to understand the attached schematic and trying to scale it to my specifications. Can anyone help me understand the circuit here?The application is to measure current in the uA and Ampere range as well. Which I need to change the shunt resistor automatically when the current consumption of DUT changes beyond the range.I am open to other suggestions for other implementations to solve the purpose.

author: gamalot
author_rank: Super Contributor
timestamp: January 12, 2023, 08:25:13 am
content: https://www.eevblog.com/forum/beginners/how-does-this-op-amp-autoswitcher-from-nordic-ppk2-works/msg4096165/

author: Anitech
author_rank: Newbie
timestamp: January 20, 2023, 07:50:20 pm
content: Thanks a lot for referring to the relevant thread. But the solution is still missing there.

author: 1audio
author_rank: Frequent Contributor
timestamp: January 20, 2023, 08:29:25 pm
content: This is a link to an autoranger to go in front of a soundcard.https://www.diyaudio.com/community/threads/autoranger-for-soundcards.299635/post-4815633Its loosely based on the input circuit of the Boonton 1120 audio analyzer. The thread is long but you should be able to get some good ideas in the first few messages.