hybridfree/eevblog-posts huggingface dataset:
looking for a usb/desktop spectrum analyzer - Page 1
Forum section: electronics / testgear

author: bug13
author_rank: Regular Contributor
timestamp: November 06, 2017, 08:49:36 pm
content: Hi guysWe are looking for a usb/desktop spectrum analyzer for 900Mhz ISM band, we are intend to use it with an 900MHz yagi (and maybe an RF filter too), to do a rough estimate of RF power radiation pattern.Our device under test will be transmitting continue signal on a rotating table, in an open field, the spectrum analyzer will be recording the signal at a fix distance. This is our best attempt to do a rough estimate with limited budget.Any recommendation for a well price usb/desktop spectrum analyzer?Thanks guys!!PS: We have consider using a RF power meter, but we think using a spectrum analyzer will give us more information.

author: BNElecEng
author_rank: Regular Contributor
timestamp: November 06, 2017, 08:52:38 pm
content: Take a look at the HackRF one. It's an SDR but can be used as a spectrum analyzer. The accuracy is not great but it might work for you.I use it for troubleshooting noisy circuits.

author: MrW0lf
author_rank: Frequent Contributor
timestamp: November 06, 2017, 09:35:11 pm
content: There is also RF Explorer in various flavours + 6GHz signal gen which will function as SNA. Could be used for simple filter testing etc. Also could hook signal gen to antenna and listen with RFEx somewhere else.https://www.seeedstudio.com/category/Ham-Radio-&-Instruments-c-c-1004%7C%7C68.html?p=0https://www.seeedstudio.com/RF-Explorer-Signal-Generator-%28RFE6GEN%29-p-2074.html

author: MasterT
author_rank: Frequent Contributor
timestamp: November 06, 2017, 09:45:26 pm
content: RTL2832 dongle/

author: Kilo Tango
author_rank: Regular Contributor
timestamp: November 06, 2017, 11:02:36 pm
content: Basically any of the decent ones would do. To give yourself an indication of harmonics maybe go for something that goes up to 2.7GHz. The HP7495, Agilent E4406 and the R & S CMU200 would all cover up to 2.7GHz and have other features that could be useful. A load of them appeared on Ebay recently and you should still be able to get one at a good price. Only problem is the HP will run on batteries, but not for long, and the E4406 and CMU200 are mains powered so a power supply is really needed.Ken

author: billfernandez
author_rank: Regular Contributor
timestamp: November 06, 2017, 11:59:11 pm
content: Don't have hands-on experience, but this looks applicable:Aaronia SPECTRAN HF-2025E V3. 700MHz to 2.5GHz. USB connection to PC. Software runs on Windows, Mac, Linux. $500 Euros.http://www.aaronia.com/products/spectrum-analyzers/HF-2025E-V3-Low-Cost-Spectrum-Analyzer/
GW INSTEK GDS-2000 Firmware source ?? - Page 1
Forum section: electronics / testgear

author: vinito
author_rank: Contributor
timestamp: November 07, 2017, 01:34:16 am
content: Hi folks. Noob here.I searched the forum for an hour and the only thing I could find were a few dead links, so please forgive if I'm screwing up by posting. But I hope someone can help.I just picked up a GW INSTEK GDS-2072A scope which arrived today. Fiddling around with it has been promising and for what I can do with one I think it should be plenty good for me for a very long while. Buying it seemed like a bit of a no-brainer since I found it new for just over $300 and I see today the same place has it priced for just over $500 - I think I got a little lucky. Yaaay.I've scoured the INSTEK website and it has several applicable downloads (one of which enabled the DVM which was cool to figure out), but I've searched high and low there and can't find what I am looking for, which is namely:What is the current firmware version number? And if mine is older, from where,oh wheredo I download the file to update it ?Seems odd that finding even the most current firmware version number should be so difficult to find. Customer Support Fail !Anyway, any help you better folks can offer is appreciated. Thanks.edit to add: I did also send a request for this info to INSTEK via their website, but often companies either take forever or never respond. I don't know if INSTEK will be one way or another, but I thought I'd ask here to cover both bases and if anybody else needs this info they can find it here too.

author: vinito
author_rank: Contributor
timestamp: November 07, 2017, 02:12:49 am
content: I just knew that would happen. I figured out what I needed right after I posted that.Just so anybody else might want or need to know, you just have to register a V.I.P. account at theINSTEK site(Member/VIP), login and then you have access to the firmware history and most current file to download - from the "downloads" area for your instrument.Alrighty then.
Tek 2467 Surgery - Page 1
Forum section: electronics / testgear

author: tecman
author_rank: Frequent Contributor
timestamp: October 29, 2017, 06:43:23 pm
content: Some months ago I picked up a Tek 2467 on ebay. Price was very good, and physically very clean, only missing one of the rear plastic feet. It powered up and was fully functional. Since the cal data seemed all okay (a quick performance check had vert and horiz all in spec) I wanted to take care of the Keeper battery for the CMOS CAL RAM. I ordered a new Keeper battery on Mouser. Seemed the best solution rather than try to replace it with a nonvolatile solution. I would get 10-15 more years for $ 15. I pulled the board and soldered a 1n914 to the cathode of CR2770 (battery in line with battery on the board). I hooked up an external lithium battery (CR123) to the attached diode and ground. After a quick voltage check, I removed the existing Keeper battery and soldered in the new one. Another voltage check and I removed the attached diode and installed the board. Powered up and all is well.I was amazed the the original battery was dated coded 1988 ! 30 years later and it still reads 3.6 volts. I also machined a heat sink I had in the bin and mounted it to U800. PS caps look good visually, and the scope works well, but next job is to replace them before they blow up.paul

author: tecman
author_rank: Frequent Contributor
timestamp: November 06, 2017, 06:55:20 pm
content: One full Saturday and it is now fully re-capped. Now working on knob/control issues. Most of the knobs are very brittle. The push-pull assembly for the "B" time base was broken into several pieces. I rebuilt it with PC7 (strong epoxy) and I am currently filing and shaping to have it fit and move smoothly.I check PS voltages and all were within spec. Still needs some tuning adjustment on the CRT to sharpen the trace a bit more. I looked at some rise times at 500 ps/div. Amazing how well you can resolve fast events with the MCP CRT. I already prefer it to my Rigol 1054 (100 Mhz modded). Many years ago I often used a 2465 at work, so it feels like home.I am again surprised how well the scope is after 30 years. No prior service work is apparent. Got to hand it to Tek for the durability.paul

author: w2aew
author_rank: Super Contributor
timestamp: November 06, 2017, 09:45:46 pm
content: Glad to hear your success - I love my 2467 too. I remember buying a few when they were new - about $12000 at the time - 3x more than the 2465 just because of the MCP CRT.
Precision decade resitor boxes VEB Schlotheim - Page 1
Forum section: electronics / testgear

author: frozenfrogz
author_rank: Frequent Contributor
timestamp: November 06, 2017, 12:11:38 pm
content: Hello fellow electronicians,I am in negotiations with someone from the small ads in Germany. He offers a big lot ofdecade resistor boxes from VEB Schlotheim(former GDR).Two sets (0,1 .. 1 .. 10 .. 100 .. 1000 .. 10000 Ohms x10) will be bought by me, there are two more complete sets including bridge connectors and additionally three 0,1 ohm, three 1 ohm, four 10 ohm and one 10000 ohm (these are all the grayish ones, not the even older silver hammer effect enamel ones).The seller seems to also have a lot of electronics stuff dating all the way back to 1889 - I requested a list of things he has stocked. He seems like a good sport and is asking reasonable prices.I thought some of you might also be interested and I could either offer to buy them all and reship to whatever location or send you the contact details to get in contact with the seller on your own.
Test equipment cost - Page 1
Forum section: electronics / testgear

author: UncleSam
author_rank: Newbie
timestamp: November 03, 2017, 04:30:47 pm
content: I am just wonder, Dave, if you have ever made a video on the cost of the lab equipment that you use? I don't recall having seen you mention this in your videos. But I might have missed one. I know that a frequency response analyzer is an extremely costly piece of equipment. But without that.... Considering only the lab equipment that you regard as vital to making all the videos you have made. Would you be willing to venture a guess?

author: Mr. Scram
author_rank: Super Contributor
timestamp: November 03, 2017, 04:41:16 pm
content: Quote from: UncleSam on November 03, 2017, 04:30:47 pmHave a look at the "how to set up an electronics lab" videos. There's both a budget and bigger budget version. That should give you some idea.

author: StillTrying
author_rank: Super Contributor
timestamp: November 05, 2017, 08:14:45 pm
content: I expecttest equipmentto be one of the things dropping in price over the next 2 or 3 months, as the world's economies collapse.

author: Mr. Scram
author_rank: Super Contributor
timestamp: November 05, 2017, 11:36:13 pm
content: Quote from: StillTrying on November 05, 2017, 08:14:45 pmDon't worry, it's just Britain leaving the EU. The rest of the world will just carry on.
Post your test equipment rebadges here - Page 1
Forum section: electronics / testgear

author: Scratch.HTF
author_rank: Regular Contributor
timestamp: November 05, 2017, 08:21:58 am
content: (originally posted at Badcaps.net)Somehow, I have managed to identify certain pieces of rebadged electronics to their OEM.If you know the rebadged model, there could be some hackability in it (especially if it runs on Linux!)So far, here are three models (Jaycar brand Digitech) I have matched to their OEM:QC-1929 = Hantek 6022BEQC-1932 = Atten ADS1022CQC-1936 = Hantek DSO4000C - it has the same cabinet as my Hantek HDG2000So if you can positively match a particular model of test equipment with its OEM model e.g. Digitech (Jaycar) and Hantek with specific model numbers, please post it here.

author: Muttley Snickers
author_rank: Unknown
timestamp: November 05, 2017, 09:24:59 am
content: I think you may discover that all of the Digitech products sold through Jaycar and elsewhere are just rebadged from various manufacturers, a large number of the Digitech multimeters Jaycar carry are made by CEM but not all of them, don't quote me on this but I'm pretty sure Digitech products are also sold internationally through a variety of other retail outlets.You can add this one to your list, the Digitech QC-1934 sold through Jaycar is in fact a Siglent SDS 1102CML. Anyway, you might want to create an editable reference list otherwise the thread will end up all over the place and not be very helpful to those seeking this type of information.

author: Cerebus
author_rank: Super Contributor
timestamp: November 05, 2017, 10:48:55 am
content: Other sellers who are infamous for rebadging and have a place the in the list:FarnellRSMaplin (Once the UK's Jaycar, now probably closer to the UK's Dick Smith, if I understand the Aussie vendor's market positioning properly.If I have a think about it I can probably add some RS kit to the list, albeit probably more historical items.

author: Muttley Snickers
author_rank: Unknown
timestamp: November 05, 2017, 11:13:16 am
content: Yes, you are spot on, I remember once posting in the Siglent SDM-3055 thread where RS Components had claimed and badged that particular meter as their own, in addition to whacking a huge margin on it compared to other existing distributors.Also I discovered this site recently which lists and compares the basic specifications of a variety of scopes, it might come in handy for somebody after just a quick comparison between models, beware though as I'm not sure how often it gets updated but I would guess it has been a while.Scopechart.comhttp://www.scopechart.com

author: PTR_1275
author_rank: Frequent Contributor
timestamp: November 05, 2017, 01:08:49 pm
content: I recently saw a tenma power supply that was a rebadge of a TTI (Thurlby Thandar). The tenma ones are going for about half the price of the tti ones on eBay too
Is it good idea to protect DMMs with new TVS diodes? - Page 1
Forum section: electronics / testgear

author: 001
author_rank: Super Contributor
timestamp: October 30, 2017, 07:20:51 pm
content: Is it good idea to protect DMMs with new TVS diodes?TVS diode much faster than varistors etchttps://en.wikipedia.org/wiki/Transient-voltage-suppression_diodeCapacitanse also smallMaybe some typical circuit avaliable now?

author: MosherIV
author_rank: Super Contributor
timestamp: October 30, 2017, 08:25:07 pm
content: It is not a good idea to try and improve the input protection of a dmm yourself unless youA) know what you are doingB) have the equipement to check the modification has the desired effect (without causing unwanted effects)(see joeqsmith thread on handheld meter robustness testing )Have a look at Dave's video on dmm input protectionGood meters (such as Fluke and Keysight) has this kind of protection

author: joeqsmith
author_rank: Super Contributor
timestamp: October 31, 2017, 09:16:21 am
content: Quote from: MosherIV on October 30, 2017, 08:25:07 pmAgree. That said, OP may just be asking why not use them. They certainly have their place. The cheap ANENG meters I looked at use one. Not that it did them much good. The poor circuit board design did a much better job protecting the electronics. Funny is some people look at this as a good thing.I used them as part of the videos I made showing a highly modified UT61E. I had several videos showing Dave's pre-production 121GW meter after I damaged it with a fairly low voltage hit. One of the videos showed the meter after I had repaired it. I added two different TVSs to the meter along with a few other changes in an attempt to harden it.My advice is start reading the datasheets. There are reasons the various techniques are used.

author: EEVblog
author_rank: Unknown
timestamp: October 31, 2017, 09:53:07 am
content: The 121GW has a TVS in lieu of the usual transistor zener pair primarily due to the unusual high voltage 15V diode mode requirement.They are pretty sweethttp://www.mouser.com/ds/2/389/sm6t-955193.pdfOne issue is that of leakage, it may upset the calibration of the high resistance ranges.Not easy to find low leakage types. The lower voltage ones typically have higher leakage.

author: 001
author_rank: Super Contributor
timestamp: October 31, 2017, 12:44:05 pm
content: Thanx a lot!I`m going to use cheap autoraging DMM (in voltmeter mode + extermnal shunt) as a panel ammeter for my DIY bench AC power supply (variac+iso transformer 220/400V)If I use cheap DMM (in AC voltmeter mode only, 50/60Hz) can I use TVS diode across external shunt to safe dmm in the case of shorting load?PS - What is typical DMM input circuit with TVSs?

author: joeqsmith
author_rank: Super Contributor
timestamp: November 04, 2017, 04:59:07 pm
content: Quote from: EEVblog on October 31, 2017, 09:53:07 amThat supply was a weak point. Was this a new change in attempt to harden that part of the design?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 04, 2017, 07:25:26 pm
content: Quote from: EEVblog on October 31, 2017, 09:53:07 amHmm, unusually well specified, I like the clamping curves.Tim
Rigol DS/MSO2xx2A-S -- How to Calibrate Generator Offset? - Page 1
Forum section: electronics / testgear

author: TurboTom
author_rank: Super Contributor
timestamp: November 04, 2017, 12:16:24 am
content: I've got a "pimped" Rigol MSO2072A-S and lately found the AWG to have some annoying DC offset (several tens of millivolts). Of course, I could compenste it by adding a DC offset via the controls but that's not the way it should be. Running the scope's internal calibration wouldn't help and I didn't find any information how to calibrate the AWG section of the scope. Does anybody know if there's a way to calibrate the AWG with the scope automatically -- maybe by linking the AWG output(s) to the scope's inputs?Even though the usefulness of the internal AWG is limited, I'ld appreciate any input on that issue. I'ld just like to have the instrument running as it was meant to be...Thanks and all the best,Thomas

author: TurboTom
author_rank: Super Contributor
timestamp: November 04, 2017, 07:08:24 pm
content: Peter-thanks for this information. Strange enough, any inquiry that's referenced to a certain channel won't work on my "pimped" MSO2072A-S. I found exactly the same commands from your list in the memory dump of my scope (what else should I expect) but apparently they are supposed to be used differently compared to your DS1xx4Z-S. Or is there a neccessity to enable calibration mode first on my model?I actually checked the inaccuracies at the output of the generator module and they are substantial and actually behave quite strange. First of all, there's a substantial gain and offset error when increasing output amplitude above 900mV (DC output). At that level, the hardware is reconfigured and probably another gain stage is inserted into the signal path (audible switching of a relay).The worst inaccuracies I get when I generate an offset square wave with eiter the upper or the lower level at 0V (i.e. 2Vpp square with either +1V or -1V offset). If the offset is positive, the 0V level is a tiny bit above 0, maybe 10 to 20mV. I wouldn't worry about that. But when the offset is negative, the 0V level is more than 200mV below zero! And funnily both channels behave very similar.To me it almost seems that the AFG has lost its calibration more or less completely. But what might have caused that? Maybe while performing a firmware update? Could there be a (hidden) self calibration function for the generator as well where the outputs are routed to the scope section's inputs? But how should this be invoked?I guess I might just ring up Rigol Europe - I had been in touch with them before and they always were very friendly and helpful - maybe they can give me a hint. Yet I'm not to sure if I want to send my highly modified scope there...Cheers,Tom
A-B problem on HP 1741A - Page 1
Forum section: electronics / testgear

author: qu1j0t3
author_rank: Regular Contributor
timestamp: November 04, 2017, 04:24:51 pm
content: I have a 1741A whose A-B mode doesn't quite work (but other modes seem all fine).If I switch a 2 channel signal to A-B, the sweep disappears far off the right edge of CRT. While BEAM FIND is pressed, it swoops back in (and looks correct).I haven't opened it up to diagnose it per service manual but I figured I'd shoot off a lazyweb question first, just in case anyone had seen something like that before. I've tried all possible POSITION settings and can't bring the trace in. (I think POSITION is operating properly in other modes.)I should add the Chan A and Chan B signals are both between 0/9V.

author: qu1j0t3
author_rank: Regular Contributor
timestamp: November 04, 2017, 05:27:27 pm
content: OK, it could be that this is just a biasing issue. I've never really used X-Y modes before so I wasn't sure if they expected a +/- range or + range. If I use AC coupling and adjust the channel V/div I can see the Chan B horiz sweep in positive quadrant (Chan A vertical is easily centred with POSITION). Pretty sure if I bias Chan B around 0V when DC coupled I can view the whole trace? Chime in if I've got any of this wrong...
Cheap 3 channel voltmeter with datalogger - Page 1
Forum section: electronics / testgear

author: 001
author_rank: Super Contributor
timestamp: November 03, 2017, 12:53:02 pm
content: Hi!I need for 3 channel DC voltage logging (1 measurment per second and 0.5% tolerance is affordable)What is the way?Buy three cheap datalogging DMMs like DT-4000ZC/TekPower TP4000ZC vs. some specialised project (I don`t hear nomore)?

author: shteii01
author_rank: Frequent Contributor
timestamp: November 03, 2017, 08:30:20 pm
content: What kind of voltages are we talking about?With a rate of 1 measurement per second and low voltage, you could use Uno and this macrohttps://medium.com/@islamnegm/quick-start-to-simple-daq-system-using-plx-daq-excel-arduino-d2457773384bto record.

author: ebclr
author_rank: Super Contributor
timestamp: November 04, 2017, 05:50:06 am
content: https://www.ebay.com/itm/iCP12-usbStick-6-Ch-USB-PC-Oscilloscope-Data-Logger-IO-ADC-DAQ-PWM-PIC18F2550/280916642088?hash=item4167efc928:g:mfUAAOSwys5WUMMB

author: 001
author_rank: Super Contributor
timestamp: November 04, 2017, 04:06:08 pm
content: Quote from: ebclr on November 04, 2017, 05:50:06 amLooks goodIs it some opensorse project or occasional ebay item?
HP 3458a assembly language programming - anybody done this? - Page 1
Forum section: electronics / testgear

author: martinr33
author_rank: Frequent Contributor
timestamp: November 03, 2017, 04:25:18 pm
content: The 3458a is a highly programmable multimeter running on a 68000 processor. It has a simple BASIC interpreter that allows for quite complex scripts.The BASIC language has an "escape" that allows you to directly execute 68000 binary code. The only thing I have found is in the manual, which describes how to call a data array.So... anybody got any examples?I did not yet find anything about what you can do in this code. For example, how is data stored and where do I find it?CALLARRAY array name, integer_listFetches the internal address of the specified array and begins execution there.The array must have been previously loaded with data (converted to ASCII)using the FILL command. The binary data must be Motorola 68000executable code written using relative addressingHere's an article talking about making the 3458a run some scope-like routines.https://www.radioexperimenter.us/1989-04/waveform-analysis-software.html
High Voltage power supply  - Page 1
Forum section: electronics / testgear

author: ankurb
author_rank: Contributor
timestamp: November 03, 2017, 01:32:17 pm
content: Hello there,My partner and I are currently working on a third go-around on a science experiment and because we have a limited budget I bought a used HV power supply. It is rather old and the meter does not seem to work (perhaps it only good for parts but I took a gamble.) Anyways, I was hoping someone might have some ideas to see if it is salvageable?As you all know HV power supplies are extremely expensive and was hoping to get lucky with this older one. Looks like it is in pristine condition internally but quite old using vacuum tube tech inside.HV light turns on but meter is not responsive and don't hear much when I turn the dial. Perhaps I need to put in a load for it to work? It uses an older octal cable it seems.Sorry, I'm mainly a theorist so really starting from the ground. Any advice or assistance would be greatly appreciated. Thank you very much for your time.Best,AP.S.I posted once before and have had very positive results in my first two experiments but was using a traditional flyback with DC supply. Wanted something a little more robust and more pure DC signal.Here are some pictures if that helps.
looking for 2-rails linear PSU - Page 1
Forum section: electronics / testgear

author: sdouble
author_rank: Frequent Contributor
timestamp: November 05, 2017, 09:42:53 am
content: Hi Folks,I'm looking for a well regulatated (at best linear) linear power supply to power an front end equipment. 10 mv p-p ripple max.Only 300 mA needed on the +9 V and 200 mA on the -5V one. The PSU should operate 24 hours 7/7I'm looking for a fixed voltage device of limited weight. A DP832-type device won't do the job, too bulky and too heavy.thanks for your help !
HP 83475a Lightwave Communications Analyser - Manual? - Page 1
Forum section: electronics / testgear

author: Chig
author_rank: Contributor
timestamp: June 26, 2017, 04:51:00 am
content: Hey crew,Anyone, by some unbelievable chance, has a pdf (or even hard) copy of the user (and or service) manual for the HP 83475a?Looked around, and haven't been able to find one myself. Closest i've come across is a manual for a 54615, which *looks* like the same vintage/series as the 83475a, so i'm guessing has a significant amount of similarity with.

author: TerraHertz
author_rank: Super Contributor
timestamp: June 27, 2017, 05:36:19 am
content: I'd have suggested artekmanuals.com (only sell PDFs), but a search there shows nothing. Maybe you should contact them and ask?

author: Chig
author_rank: Contributor
timestamp: June 28, 2017, 02:08:36 am
content: No joy, sadly.He was certainly quick to reply though, will keep him bookmarked for any other manuals i need sourced.

author: ghpicard
author_rank: Contributor
timestamp: November 03, 2017, 03:07:15 am
content: Hi there,If you look in this guy's pagehttp://emperoroftestequipment.weebly.com/you will see that the HP 83475 is equivalent to the HP 54610 and he also has the manual in PDF format.It seems worth an email.
Fluke 80i-1010 Teardown and repair video  - Page 1
Forum section: electronics / testgear

author: PA4TIM
author_rank: Super Contributor
timestamp: November 02, 2017, 07:22:36 am
content: I had a Fluke 80i-1010 in for repair. There is almost no info about this AC+DC current probe on the net. Not even on the Fluke site. So I made a video about it to show what is inside and how to repair it.It is in 2 parts because of the length. My laptop is rather slow and internet where I live is still powered by steam and smoke signals. 30 minutes takes a night to upload so I still can use my laptop during the day.https://youtu.be/gabDPs2LavEhttps://youtu.be/LMHDX8FLCpk
Looking for compact insulation tester - Page 1
Forum section: electronics / testgear

author: 001
author_rank: Super Contributor
timestamp: October 31, 2017, 03:36:21 pm
content: I`m looking for compact insulation tester to check DIY transformer isolation with 1kV DCV (1.5kV will be awesome)Since it is only insulation, acurasy of +/-25% will be okCan I find some afordable toy at ebay/ali? (is it usable?https://www.ebay.com/itm/HDT20A-LCD-Digital-Insulation-Resistance-Tester-Megohmmeter-Meter-1000V-Hot/361857687789?epid=16004017841&hash=item54406620ed:g:ki8AAOSwa~BYV5T2)May be somebody made some DIY wariant of insulation tester? Help with the schematic pleaseThanx!

author: Mr. Scram
author_rank: Super Contributor
timestamp: October 31, 2017, 04:08:50 pm
content: Quote from: 001 on October 31, 2017, 03:36:21 pmWhat did your research turn up? It seems you're starting a lot of "what to buy" threads, but there is a lot of great information out there. It would help if you could post the things you've looked at and why you liked some, and didn't like others.

author: 001
author_rank: Super Contributor
timestamp: October 31, 2017, 04:15:46 pm
content: NOT TURN. BUT INSULATION of my self made transformersNow I use this muscul-powered monster

author: Electro Detective
author_rank: Super Contributor
timestamp: November 01, 2017, 09:44:17 pm
content: If you prefer or are used to the analogue meter style, the KYORITSU 3132A or a rebadged model like Sperry etc is a nice insulation tester that supplies 250V/500V/1000+ Volts of DC juice,has Ohms/Continuity test and a voltage alert in case the DUT is energized.It takes 6 AA batteries, compact with a protective cover, and easy to use with no menus or multifunction digital wankery to think about when you're busyThe TEST button can be pressed when needed, or pressed and turned for continuous insulation 'zap'with auto dischargeThey are common and well priced if used, and easy to test with any multimeter if they are ok or not,just check for battery leakage if buying used.Bear in mind that you have to half or double what the meter reads at 250v and 1000v positions, because the 3132A meter needle calibration is set for the 500v standard,whereas a digital tester gives a direct readout = no big deal or major math workKeep your windup one too, because it works without batteriesThere are some decent cheap digital insulation testers too, get one with DAR and PI functions if affordableIf you do a lot of insulation testing, or for peace of mind, it's handy to have an analogue, digital, and a manual windup tester to double check and verify your work

author: 001
author_rank: Super Contributor
timestamp: November 02, 2017, 01:20:48 pm
content: It is interstingCan You help me with some nowday meggers service manuals or schematics?
Instek PSM-6003 FW ROM? - Page 1
Forum section: electronics / testgear

author: dgtl
author_rank: Regular Contributor
timestamp: November 01, 2017, 08:20:21 pm
content: Does anybody have the FW image of GW-Instek PSM-6003 power supply?I got a non-operational GW-Instek PSM-6003 linear DC supply. The story goes that the unit was working in a PC-controlled setup and then suddenly completely died. I've checked the uc board and everything looks okay (supplies are fine, reset is not asserted and crystal is running), no activity on the 8052-based W78E516 uc other than ALE pulses and external WDT reset pulsing every so often because it is not reset, all other pins not moving. I took the socketed chip out and read back the contents. The LDROM part was fine (strings like "Erasing" and "programming" visible etc), but the APROM was cleared to FFs, the lock bits were not set (they would not allow the LDROM to be read back either). It seems that there exists some kind of FW update functionality, the chip can reboot from LDROM and then erase and reflash the APROM part. My theory is that the RS232 communication from PC got messed up in some way and it happened to trigger the FW update procedure, that erased the FW and then the supply was bricked...I would try to program the uc APROM if I could get the FW image file somewhere. Alternatively, I could try to get another uc and program that. The biggest issue is getting the FW image file.
SKY Top Power STP3005 - noisy switching supply - Page 1
Forum section: electronics / testgear

author: bbt95762
author_rank: Contributor
timestamp: August 19, 2017, 08:16:37 pm
content: Hey, I recently purchased a SkyTopPower STP3005 switching supply from eBayone of those you get what you pay for moments I thinkincredibly noisyhttps://youtu.be/r0OCPXS96ogbut, for $30...must be some way to clean it up. I'm guessing if I open it, I"ll find no chokes or caps, anyone else have experience with this supply?Thanks,Brian.

author: bbt95762
author_rank: Contributor
timestamp: September 13, 2017, 07:37:35 pm
content: on the bright side, the eBay seller seems genuinely interested to solve the issue.I snapped this photo of the inside (we tried some additional caps between +, -, and EARTHI was surprised the high side caps are much bigger (10000uF) then the output side caps 470uF)

author: electronhauler
author_rank: Newbie
timestamp: November 01, 2017, 06:22:11 pm
content: If you can add a common mode choke and a couple of ground capacitors to the output it will reduce the noise.See attachment
Simple VGA DAC for Hantek HDG2000 and certain others - Page 1
Forum section: electronics / testgear

author: Scratch.HTF
author_rank: Regular Contributor
timestamp: November 01, 2017, 02:02:13 am
content: I made this since I am adding a Raspberry Pi inside for my "ultimate workbench" with many great functions.From what I have measured on the HDG2000, DCLK frequency is 26.666667 MHz (1/15 core frequency) with H/V frequencies of 30.24kHz/56.94Hz and a low Horizontal blanking overhead (82 pixels) and short Horizontal Sync (8 pixels) which may have issues (especially size and positioning) when used with a simple VGA DAC (resistor based, as shown below) and certain LCD panel controllers or VGA-HDMI converters (may be detected as either 800x480 57 Hz or 640x480 57 Hz).This would be less of an issue by increasing the video clock frequency to 33.333333 MHz (1/12 core frequency which corresponds to the typical DCLK value for the AT070TN92 display) along with changing the Horizontal parameters to correspond with VESA 800x600 @ 56Hz and the Vertical parameters to correspond with IBM 640x480 60 Hz resulting in a H/V frequency of 32.55kHz/62Hz.I do not recommend soldering directly to the FPC connector as solder can bridge the tiny gaps between pins on this connector, so FPC breakout boards are strongly recommended.A simple VGA DAC (+3.3V) is shown below:Bit5 -300R-200R-\4 ----1K0------*---*---- OUT (0-0.7 Vpp) assuming 75R termination3 ----2K0------* |2 --2K0-2K0--* 61 --6K8-1K2--* 80 -----16K-----/ 0R|GNDAll resistors are 1% units.Only one channel is shown; use 120R series resistors for H Sync and V Sync.Here is the pinout of the LCD panel interface:|-----------------------------------------|2 40| | | | | | | | | | | | | | | | | | | || | | | | | | | | | | | | | | | | | | |1 391 Switched +5V 2 Switched +5V3 Backlight ON 4 GND5 GND 6 +3.3V7 +3.3V 8 Mode9 Data Enable 10 /V Sync11 /H Sync 12 GND13 Blue 5 14 Blue 415 Blue 3 16 GND17 Blue 2 18 Blue 119 Blue 0 20 GND21 Green 5 22 Green 423 Green 3 24 GND25 Green 2 26 Green 127 Green 0 28 GND29 Red 5 30 Red 431 Red 3 32 GND33 Red 2 34 Red 135 Red 0 36 GND37 /Clock (DCLK) 38 GND39 Left/_Right 40 Down/_Up
Suggestion: Test equipment Wiki - Page 1
Forum section: electronics / testgear

author: tszaboo
author_rank: Super Contributor
timestamp: October 27, 2017, 02:36:18 pm
content: I have a suggestion to make. We should put our heads together and create a Wiki for test equipment.We should start probably with something simple, like multimeters and see if this works, or not.The main reason for this would be the scarcity of information. Manufacturers disappear, or they discontinue a product, and all the info on their product page just disappears. For example if I search for the basic DCV accuracy of a Fluke 8840A, there is no easy way of finding it. I either have to download the instruction manual from Fluke, and search for the tables, or got to some third party website and look at incomplete specification.Dave, I'm wondering if you would be interested of web hosting this? It could be under the EEVBLOG wiki.I know maintaining a wiki is not a small task, but there is definitely a need for this.

author: Old Don
author_rank: Regular Contributor
timestamp: October 27, 2017, 05:45:41 pm
content: Sometimes the Wayback Machine will have a stored web page or two with the information you need. Not often that it will have any of the downloads, just the web pages. Helps if you have the full www.... address to enter!See:https://archive.org/web/

author: tszaboo
author_rank: Super Contributor
timestamp: October 30, 2017, 09:47:33 am
content: Well, I guess it was a bad idea.

author: TiN
author_rank: Super Contributor
timestamp: October 30, 2017, 10:12:09 am
content: Maybe not bad idea, but just not feasible as hobby. It's a hard and very time consuming work even just to structure and format all the stuff.I mean look atnearby thread about DMMsto get the idea.Hosting is not even a question, that is zero problems today. So I'd think you definately underestimate "small task" here. I have ~200 articles on my site and I spent at least10 timesmore time refining the content and correcting for mistakes, than actual fixing gear or running the test. And that is still, limited to only what I'm interested about, not everything out there, not even 0.001%.

author: tszaboo
author_rank: Super Contributor
timestamp: October 31, 2017, 09:28:52 am
content: Quote from: TiN on October 30, 2017, 10:12:09 amAnd that is why I'm suggesting a wiki. Something which is crowd sourced, and not maintained by one person. Right now, all this information is scattered around the web, not structured, not maintained, and lost.
Keithley 2450 - constant power battery discharge & distributor recommendations - Page 1
Forum section: electronics / testgear

author: Sparky
author_rank: Frequent Contributor
timestamp: October 30, 2017, 05:27:18 am
content: Hello friends!I want to tackle Zinc-Air battery discharge testing and it seems the 2450 is the "go to" equipment for performing such tests, especially as you can then load the data as a battery model to the 2281S and reliably simulate battery conditions and check for weird behavior of your device as you approach the drop-out voltage. I think that can be super helpful for testing low-power wireless devices that might start behaving unpredictable at critically low voltages.I have read some Keithley app notes and watched YouTube videos and it looks as thoughthe 2450/2460 only allow Constant Voltage (CV) and Constant Current (CC) discharge-- I didn't see any option for Constant Power (CP). Is there any "work around" for attempting CP discharge with 2450? Must one use a dedicated DC load to achieve constant power loads?I have checked our EEVblog test equipment friends (TEquipment.NET, Saelig) for discounts but neither of them are distributors for Tektronix/Keithley. Could anyone recommend a distributor in the US that is good for pricing of Keithley equipment? It would be a great help!Best wishes!Sparky

author: HighVoltage
author_rank: Super Contributor
timestamp: October 30, 2017, 09:46:46 am
content: 1.) You should be able to achieve constant power discharge through a script. It is almost limitless, what you can do with script programming in the 2450 and 2460 SMU.2.) You might be able to get the best price or a significant discount at Keithley / Tektronix directly for a "demo" unit with full warranty and all accessories. At least, here in Germany, Keithley is offering these "demo" units for sale.

author: Sparky
author_rank: Frequent Contributor
timestamp: October 31, 2017, 12:50:26 am
content: Quote from: HighVoltage on October 30, 2017, 09:46:46 amThanks @HighVoltage! Using scripting is a great idea! One can read back the voltage and then adjust the current for a specified power. I wonder how much iteration would be needed? Adjusting the current might cause a voltage change (particularly if the battery is new or approaching 100% discharge)...and one would need to adjust the current again based on updated voltage measurement, etc, etc. Perhaps it wouldn't be too bad, especially during the time where the voltage of the cell is flat.Thanks for idea of the demo unit! That's great suggestion -- I will check it out!
Prema 4000 6.5 Digit Multimeter - Page 1
Forum section: electronics / testgear

author: BNElecEng
author_rank: Regular Contributor
timestamp: October 30, 2017, 04:30:42 pm
content: Hello everyone,I've recently bought a Prema 4000 multimeter as my first foray into the world of higher precision measurements. I'm planning to put my own version of the Mini Metrology Lab together.I couldn't find an existing discussion about this multimeter, so I thought I'd create a new topic.Has anyone used the Prema 4000 in the past? If so, could you tell me about your experiences with it? I'd like to find out about quirks early on if possible.Thanks

author: guido
author_rank: Regular Contributor
timestamp: October 30, 2017, 06:30:08 pm
content: Seems closely related to the 5000. If you look at the manualhttps://prema.com/index.php/en/service-en/maintanance-of-measuring-instruments, then the schematics are for the 5000. Not sure what the difference is.The 5000 is more common i think. I have two. Be careful with the handling. The case is bomb proof. But the ICs are in cheap sockets. One small moment of not having contact and the calibration RAM is empty (in mine 21C14 ICs, one of the three RAM chips has battery backup). I modified my meters, adding a specific IC handling the battery backup. Wiring the VCC, GND and CS direct, without using the socket. Obviously you then need to re-calibrate them.I also changed the PS caps and replaced the chopper amp in one (it was a bit "noisy").

author: BNElecEng
author_rank: Regular Contributor
timestamp: October 30, 2017, 08:08:58 pm
content: Thanks for the heads up. I'll take mine apart carefully and see if anything needs to be put back into place after being shipped.The specs on the 4000 aren't going to be winning any awards but I'm hoping it'll be a good stepping stone to more precise measurements.If you have a rough schematic of your battery backup circuit, I'd like to see if I can make it work before I take it for calibration.

author: Kleinstein
author_rank: Super Contributor
timestamp: October 30, 2017, 09:20:18 pm
content: I think I have used one of the similar looking DMMs, but can't remember the exact model.AFIAR it was reasonable for it's time and price - I remember it was one of the cheapest 6 digit DMMs at that time (1990s). I used it extensively for thermocouples (thus low voltage) and it worked quite good, including the scanner I had inside. There seemed to be some noticeable DNL, I am not used from other DMMs : not all numbers appeared equally often, even visible from the display.
I just got my first oscilloscope! - Page 1
Forum section: electronics / testgear

author: altmangf
author_rank: Newbie
timestamp: October 30, 2017, 03:21:48 am
content: I finally got an oscilloscope! It's a Tektronix 2335 given to me by a generous neighbor in exchange for a 6-pack of Sanitas Black IPA. Nice!Looking forward to calibrating the unit, as I'm sure documentation is readily available online. I've never calibrated a scope...what could possibly go wrong.The handle is/stand is missing. Did these scopes use a standard form factor for the case? Maybe handles from other Tek oscilloscopes will fit?

author: radhaz
author_rank: Regular Contributor
timestamp: October 30, 2017, 03:28:59 am
content: Congrats!

author: tggzzz
author_rank: Super Contributor
timestamp: October 30, 2017, 09:02:12 am
content: Don't even think about calibrating it until you are very familiar with how scopesand probesshould be used and how they work. You run the risk of misunderstanding something and screwing up your scope!Have fun using it

author: rstofer
author_rank: Super Contributor
timestamp: October 30, 2017, 02:53:45 pm
content: ^^^^ This!Why mess with it? Scopes are an 'about so much' kind of instrument. A little + or - doesn't mean much. I've been using scopes for a very long time and I have never removed the cover from my Tek 485. It still shows traces, they pretty much look like what I expect and the Time/Div seems pretty close. I don't even have the service manual because I know I don't have the tools or the capability to service it. It works! No need for me to break it...
+/- 12V PSU for Keysight N2782B current probe (solved) - Page 1
Forum section: electronics / testgear

author: HighVoltage
author_rank: Super Contributor
timestamp: October 29, 2017, 05:14:55 pm
content: For a Keysight N2782B current probe that I bought without a power supply, I need a +12V / -12V power supply.I am looking for alternatives to the original Keysight N2779A PSU, which cost is about Euro 1300 in Germany.I want to build my own 230V power supply for this current probe but I don't want to do it from scratch.The specs are (Based on the N2779A Datasheet):+/- 12V2.5 A maxDoes anyone here have a suggestion, of what kind of power supply I could buy that has good dual output +/- 12V?

author: Someone
author_rank: Super Contributor
timestamp: October 30, 2017, 12:07:39 am
content: You wont need 2.5A for that probe, 250mA per rail is sufficient.

author: HighVoltage
author_rank: Super Contributor
timestamp: October 30, 2017, 12:43:45 pm
content: OK, after looking around for a while, I found a suitable PSU by Traco Power+/- 12V at 1A per channel, medical quality.This should work great.I will post some pictures, when I get it.
Rigol DS2072 math A-B doesn’t work. Others okay - Page 1
Forum section: electronics / testgear

author: Circlotron
author_rank: Super Contributor
timestamp: October 29, 2017, 08:17:57 am
content: Firmware 00.03.05.SP3Hardware version 2.I want to use differential input mode so channel 1 normal and invert channel 2 and use math A-B function. Purple line is flat no matter how far up the sensitivity is wound. Other simple arithmetic functions appear to be okay.Anyone else see this?

author: texaspyro
author_rank: Super Contributor
timestamp: October 29, 2017, 06:01:12 pm
content: Quote from: Circlotron on October 29, 2017, 08:17:57 amch1 - (-ch2) would display ch1+ch2. I don't think you want to invert channel 2 for a differential display if you are using an (A-B) math function.

author: Circlotron
author_rank: Super Contributor
timestamp: October 29, 2017, 10:14:59 pm
content: I tried every combination of normal and inverting of both channels but still no cigar.

author: JDubU
author_rank: Frequent Contributor
timestamp: October 30, 2017, 02:09:38 am
content: I also have a DS2072 with hardware version 2 and firmware v00.03.05.SP3.I connected both probes to the scope's square wave calibration output lug with channel 2 set to invert.Here is a screenshot using Math A-B. Note that Source A and Source B need to be set in the math controls

author: Circlotron
author_rank: Super Contributor
timestamp: October 30, 2017, 04:56:28 am
content: Quote from: JDubU on October 30, 2017, 02:09:38 amThat was it. Both sources were set as Ch1. The tricky part was that AxB, A/B and A+B all still give a reading of sorts so I never thought of that. What's more, I have only ever used the advanced option, and with that you type in an equation that has the choices of Ch2 and Ch2. You don't have to assign them as such.
Function Generator Reccomendations - Page 1
Forum section: electronics / testgear

author: Tom10000
author_rank: Contributor
timestamp: October 30, 2017, 03:31:30 am
content: I have Been looking for a function generator for the last 10 minutes and i just didn't know wich one to buy please could i have any recommendations i am willing to spend about $60 Australian Dollars.

author: ataradov
author_rank: Super Contributor
timestamp: October 30, 2017, 03:59:20 am
content: At this price, you don't have too many options. I will be something like thishttps://www.ebay.com/itm/Digital-DDS-Dual-channel-Signal-Generator-Source-Frequency-Meter-Counter-25MHz/252183431116. They do work, but have terrible UI.
DC Load for PSU test - Page 1
Forum section: electronics / testgear

author: g0mgx
author_rank: Regular Contributor
timestamp: October 27, 2017, 05:53:52 pm
content: Has anyone got any experience with one of these:http://www.ebay.co.uk/itm/DC0-5-60V-Load-Battery-Tester-150W-Constant-Current-Electronic-Discharge-Load-AM/282580693059?hash=item41cb1f3043:g:1u4AAOSw0hRZcZ7gImage attached.Very interested in any feedback or experience with these devices.MarkG0MGX

author: exe
author_rank: Unknown
timestamp: October 27, 2017, 09:42:59 pm
content: I have one, it works. I used it to measure LiPo capacitance. It's a pretty basic unit, though. No chopping, no curves plotting, no constant power, etc. Just a load. 150W sounds a bit too optimistic.I'm pretty sure there are more detailed reviews on youtube.

author: exe
author_rank: Unknown
timestamp: October 29, 2017, 08:13:30 pm
content: BTW, I just watched the review from VoltLog, seems there are fake units that look very similar to the real one. So, be sure to read comments in review:(but he reviewed a fake one).I don't know if mine is genuine or not, but I'm happy with it. Readings are accurate on mine, no 10% errors, but I tested up to 30W (maximum for my PSU).

author: g0mgx
author_rank: Regular Contributor
timestamp: October 30, 2017, 08:50:25 am
content: I've ordered one from AliExpress with good feedback.So now we wait a month or two!Thanks for the pointers, appreciated.Mark