hybridfree/eevblog-posts huggingface dataset:
Scope Recomendation - Page 1
Forum section: electronics / testgear

author: Sienna
author_rank: Newbie
timestamp: November 03, 2013, 01:07:58 pm
content: Hello,I am in the market for my first Oscilloscope. Mostly I deal with micro controllers, so debugging microcontrollers / PWM circuits will be the primary intended usage for the scope. (I recently acquired two ebay LAs, a LogicPort and a Tek 1240, so that side is covered.)In the end, I would like four channels. The current fastest micros I deal with are the ~30MHz ARM chips. (Next step, playing with the 200MHz PRU in the BBB.) The PWM signals I will be debugging are in the 2.5MHz range (current limit of high power LED controllers), so not really very high.I am looking for suggestions on a new scope:1) Buy a DS1074Z (I had one on order with Tequipment, only to find out it is a ~4 week delay.) While this is definitely the cheapest option, I am starting to wonder if the 250Ms/s will be the limiting factor on this scope.2) Upgrade to a DS1104Z (same concerns over 250Ms/s).3) Buy one DS2072 now, and another one later. Still cheaper then the DS4000 series, and possibly provides more flexibility later. I am anticipating that one of the LAs would be able to concurrently trigger both scopes, correct? Or is it not advised to view three / four related signals on two scopes (say Sync PWM, Input PWM, and LED PWM at once)4) Save for a few months, and get a DS4000 series.5) Some other brand the good folk at EEVBlog recommend?Thanks in advance for any suggestions.

author: Nermash
author_rank: Frequent Contributor
timestamp: November 03, 2013, 01:21:07 pm
content: I would either go with Rigol DS4000 or wait a few months untill the new Siglent 2000 series hits the market.

author: quarros
author_rank: Regular Contributor
timestamp: November 03, 2013, 01:31:34 pm
content: Quote from: Nermash on November 03, 2013, 01:21:07 pmI second that. The Rigol 4000 have one additional advantage tough. It can be easily hacked to have all the triggers and decoding as far as I know.
HyElec Power Supply - Page 1
Forum section: electronics / testgear

author: simpson
author_rank: Contributor
timestamp: November 02, 2013, 07:53:01 pm
content: I picked up this HyElec 3003D DC power supply for $20 at an estate sale this morning. It seems to be in mint condition and working fine. It even came with a pair of leads.I'm not familiar with this brand but it appears to be the same as the Mastech unit with the same model number. It is a single output 30v/3A supply. It seems like a step up from my little $10 kit-built supply that I've been using. At this rate I might soon start to look like I know what I'm doing.Anyway, does anyone have experience with these?

author: Zbig
author_rank: Frequent Contributor
timestamp: November 03, 2013, 01:00:09 pm
content: I wouldn't call it a brand, really. You can find the exact same design under metric gazillion of different names. Had you ordered just enough of these from the Chinese guys who make them, they'd probably be happy to slap "simpsonElec" there for you as a bonus.
dso 2072a with options - Page 1
Forum section: electronics / testgear

author: JohnnyGringo
author_rank: Regular Contributor
timestamp: November 03, 2013, 12:34:56 am
content: When I purchase a Rigol 2072a, do I need to specify the options that I want at the time of the purchase? Or can I just order options as they become needed? Would I have to send the scope back to Tequipment for them to do the upgrade, or do they just send me a OS upgrade/patch?Surely, someone in this forum has actually paid for some options/bandwidth before?-Thanks,

author: AndreaEl
author_rank: Contributor
timestamp: November 03, 2013, 12:47:18 am
content: You can buy now the oscilloscope without any option and buy late the option.With the code of the option that you have buy and your serial N of oscilloscope go to the rigol website and you will have the code for install the option in you oscilloscope.When you buy the oscilloscope you have full memory, but it's limited by software if you not enter the key for the memory upgrade option.
Fluke 187 continuity no beeper sound - Page 1
Forum section: electronics / testgear

author: mianchen
author_rank: Regular Contributor
timestamp: November 02, 2013, 12:46:28 pm
content: I have received my newly scored Fluke 187 this morning. The meter looks pretty new. It was calibrated (no date, but there are 2 stickers on it, and look relatively new and clean). The range switch is working and has a nice feeling to it when turning. Quick test with myChinese voltage refgave almost same readings (minus 1-2 digits depending on range) on that little "certificate". Ohm/diode/temperature/DC mA/DC A and Cap everything seems fine and is very responsive. However the continuity buzzer doesn't seem to be working. This function itself seems to be ok: The bar graph is responsive so is the reading...I have replace the batteries with 4 fresh Duracells AA - no difference.I had a look at theuser manual. There isn't anything related to muting/unmuting the buzzer. Does anyone know what is going on? I may have to take it apart later (don't want to do it now in case I need to return it - I like it, will accept a none working buzzer anyway, but just in case there are more probs).

author: ModemHead
author_rank: Frequent Contributor
timestamp: November 02, 2013, 02:48:34 pm
content: Some piezos are mounted in the case parts and have contacts you can clean, but this one is soldered on the board. A scope will probably help to find out if it's the element or the driver.

author: Unknown
author_rank: Unknown
timestamp: November 02, 2013, 02:52:06 pm
content: Is beep enabled in the setup menu?

author: mianchen
author_rank: Regular Contributor
timestamp: November 02, 2013, 06:35:34 pm
content: Quote from: alm on November 02, 2013, 02:52:06 pmbingo

author: nanofrog
author_rank: Super Contributor
timestamp: November 03, 2013, 03:52:26 am
content: Quote from: mianchen on November 02, 2013, 06:35:34 pmDon't beat yourself up. At least it all works.Enjoy your new.

author: mianchen
author_rank: Regular Contributor
timestamp: November 03, 2013, 01:28:04 pm
content: Quote from: nanofrog on November 03, 2013, 03:52:26 amI don't really want to bump the thread showing my £&$*£^ moment, but I have to say, I like this meter, and thank you for the reply

author: SeanB
author_rank: Super Contributor
timestamp: November 03, 2013, 02:15:02 pm
content: We have all had those moments........ I was going nuts tracing a phone cable when I suddenly realised the end plugged into the wall was loose, as the clip had broken but the helpful user had pushed it into the network socket next to the phone socket.......

author: Lectricman
author_rank: Newbie
timestamp: November 04, 2013, 10:13:38 pm
content: The Fluke 187 is a really great meter. Congrats ! You will really enjoy it. I have used mine for 7 years now.
Since Rigol CS just... - Page 1
Forum section: electronics / testgear

author: Dark Prognosis
author_rank: Regular Contributor
timestamp: November 03, 2013, 02:34:21 pm
content: sucks and their technical department holds your equipment hostage for months on end I have a question.I am saving Amazon dollars for a scope and I was going to do the Rigol 1102E in January as I will have over 400 Amazon dollars by then. So, which scope do I get for that? Seems the Rigol has the market tied up at that price range but with the stuff I am seeing out of Rigol they will not get a penny from me unless they suddenly drop that Asian mindset of losing face and fix what is broken from them after the fact.Dave showed them a glitch recently but I think he publicly called them out at a show and they had no choice but to eat some crow and quickly try to save face. You tell them something is wrong via email or sending in your unit and that is where their ugliness kicks in, or so I have read too many times.So, now what?!?
isr658 - Page 1
Forum section: electronics / testgear

author: trebor
author_rank: Newbie
timestamp: November 01, 2013, 11:40:14 pm
content: hii have an isr658 oscilloscope i bought off ebay a few months ago, all was good but now somestimes it will not come on although the on light is on nothing comes on screen, after several attempts it will come on. can anyone suggest a likely suspectthanks

author: Whales
author_rank: Super Contributor
timestamp: November 02, 2013, 12:37:00 am
content: Are you sure it is simply not needing a little while to warm up?If not, it could be a great range of things, including poor solder joints or corroded contacts. I fixed my analogue scope by cleaning all of the jumpers between boards. I would recommend you do a visual inspection inside for anything looking burnt, bulging or bad, then clean all of the jumper contacts with a little bit of very fine sandpaper.SERIOUS SAFETY ADVICE:DO NOT open up any analogue scope (nor CRT TV for that matter) without first researching how to discharge the tube capacitance! It will go *thwump* and kill you with a manic laugh if you do not do so!

author: trebor
author_rank: Newbie
timestamp: November 02, 2013, 12:39:38 am
content: yeah it does take little while to come on, but i leave it for a similar time each time and some time it works other times no display
HP 3325A  & 3580A - Page 1
Forum section: electronics / testgear

author: faguotek
author_rank: Newbie
timestamp: May 03, 2013, 04:31:26 pm
content: Hi all,I am looking for a complete set of knobs for my HP3580A, seems very difficult to find. Does anyone knows where to find that ?I am also looking for 3325A A6 board, or a set of ROM and RAM, mines are dead, and my machine does not work anymore.Thanks for your help.Steven.

author: ddavidebor
author_rank: Super Contributor
timestamp: May 03, 2013, 07:20:43 pm
content: Are you sure rom is dead?Usually is nly nvram with dead batteries.

author: PaulAm
author_rank: Frequent Contributor
timestamp: May 03, 2013, 09:06:45 pm
content: k04bb has 3325b rom images; I'd swear I saw the A versions at some point. You can try on the hp_agilent_equipment yahoo group. You're probably going to have to find some proms or eproms and burn the image, or find a replacement processor board.

author: faguotek
author_rank: Newbie
timestamp: May 04, 2013, 11:54:09 am
content: Hi !Paul.Thanks for your suggestion. I already post a message on HP group !I suspect the ROM to be dead. I already change 95% of SN74xx, and nothing change...My machine is A model, not B. Do you think 3325B wirmware fit the A model ?

author: vk2hmc
author_rank: Contributor
timestamp: October 07, 2013, 09:38:40 pm
content: Steven,Hopefully your 3325A is fixed by now?If not, did you ever get your hands on a A6 board or the Roms?I probably have a working A6 board I could use for exchange (depending on the condition of the old one) with your defective.--marki

author: eurofox
author_rank: Unknown
timestamp: November 01, 2013, 09:15:26 am
content: Quote from: faguotek on May 03, 2013, 04:31:26 pmI'm looking as well for a complete set of knobs for my HP3580A for the restauration of the instruments.I'm ready to buy a "dead" complete instruments for the knobs.eurofox
Prices for Tektronix TLA - Page 1
Forum section: electronics / testgear

author: echen1024
author_rank: Super Contributor
timestamp: November 01, 2013, 02:30:54 am
content: I would like the fair prices for the Tektronix TLA600 series of portable LAs, and possibly the 721 benchtop unit and the 714 portable. I'm looking to spend no more than $500, unit + cards. I have the P6417 probes already. the
Blog Writing - Page 1
Forum section: electronics / testgear

author: welshmike
author_rank: Newbie
timestamp: October 31, 2013, 02:36:13 pm
content: Hello,I'm looking for someone to write one or two blogs each month for a Test & Measurement website. (please note these will not be guest blogs and will be owned by the website.)Please email with any interest.ThanksMike

author: Bored@Work
author_rank: Super Contributor
timestamp: October 31, 2013, 02:46:36 pm
content: Quote from: welshmike on October 31, 2013, 02:36:13 pmSo why do you use the subject line "Guest Blog"?And may I guess, the blog entries have to be written for free?

author: welshmike
author_rank: Newbie
timestamp: October 31, 2013, 02:48:22 pm
content: Good Point, I will look to change that.And no I do not expect the blogs to be written for free.
Tekpower TP3711A Programmable DC Electronic Load - Page 1
Forum section: electronics / testgear

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: October 30, 2013, 10:57:07 pm
content: Does anyone have experience with the Tekpower TP3711A Programmable DC Electronic Load. This is a 300W, I am also looking at the BK Precision 8500 which I believe is also a 300W. The BK has better resolution than the Tekpower but also is twice the price. Any thoughts?

author: Unknown
author_rank: Unknown
timestamp: October 30, 2013, 11:15:30 pm
content: I believe this is a rebadged Array load. Some information:https://www.eevblog.com/forum/testgear/why-is-bk-precision-still-in-business-bk8500-programmable-load-oem-found/15/https://www.eevblog.com/forum/testgear/array-electronic-loads/Google findsseveral more threads

author: reagle
author_rank: Unknown
timestamp: October 31, 2013, 01:40:54 am
content: I have one- it is indeed a rebadged Array. Seems to be well built, but missing pulse load mode- you have to use their crappy PC GUI to program a waveform or enter it manually. Otherwise no complaints
Voltcraft HPS-13030 - Page 1
Forum section: electronics / testgear

author: eurofox
author_rank: Unknown
timestamp: October 31, 2013, 06:45:02 am
content: Hi guy's,I bought on eBay Germany 3 instruments (not working) to check my “repair knowledge” :1 Process calibrator (from customer return) , was repaired in just an ½ hour1 nice Voltcraft multimeter (from customer return) and as well repaired in an ½ hour1 nice power supply Voltcraft HPS-13030, this one is giving me hard time, I just wonder if someone got a schematic of this.I can see that already other people try to repair it, the strange thing is that it work ok but the display give 50% of the real output voltage. The front panel, voltage, current and display is driven by a CPU.It is really an interesting device, very small footprint for a 900 W power supply.Is in fact the same power supply than this one.Any idea to help me is welcomeeurofox
Signal Distribution Box - Page 1
Forum section: electronics / testgear

author: jbrewton
author_rank: Newbie
timestamp: October 30, 2013, 07:32:37 pm
content: New to the forum, but have been watching Dave for a while. I saw a video where a guy had a distribution box to distribute an audio signal to a counter, oscilloscope and distortion analyzer all at once. Anyone used these in the past? Recommendations?
Risetime of hacked DS2072 - Page 1
Forum section: electronics / testgear

author: Circlotron
author_rank: Super Contributor
timestamp: November 02, 2013, 10:39:39 am
content: Got a 100nF polypropylene cap with 10mm leads, charged it to 12.6V on a battery then applied it directly to the BNC connector of the scope. Had to try it about a dozen time to not get any "contact bounce" but finally got a clean waveform. As you can see from the pic, 1.44ns risetime, 11.44% overshoot. That'll do me just fineWould be interesting to see what other people get for this easy-to-do test, particularly in comparison to a non-hacked DS2072, and other scopes too for that matter. Use a good low impedance film cap with short leads, not an electro!

author: BravoV
author_rank: Super Contributor
timestamp: November 02, 2013, 12:13:39 pm
content: Better tool & far more reliable method ->EEVblog #306 - Jim Williams Pulse Generator
High Speed measurements with the Keithley 2110 DMM - Page 1
Forum section: electronics / testgear

author: trevwhite
author_rank: Frequent Contributor
timestamp: October 30, 2013, 09:45:09 am
content: Hi all.I wanted to test how well the KEITHLEY 2110 DMM works with high speed measurements. I decided to measure a 1KHz signal going in and take 1000 measurements - all being written to the internal store of the device.The manual says to set the NPLC to 0.001 for a really low integration time - 20uS integration. It also states in the manual it is possible to take 50,000 readings per second so I think it should work.Well I assumed I would end up with a set of results that would represent a square wave. But it didn't come out that way, it came out as a stable average voltage of 50% the peak square wave voltage. I do not know if the ADC is holding charge but can anyone help with setting the DMM up to make this type of measurement work? Maybe my understanding of the meter's performance is wrong?My end goal is to measure uA current of a processor and measure changes of current over a few 100ms so I need to know the measurements are good and working. The 1KHz voltage signal is my way of checking I can set the DMM up properly and calibrate how fast the ADC converter tracks changes in input.Really appreciate any help.ThanksTrev
A used agilent 34401A - is the price right? - Page 1
Forum section: electronics / testgear

author: JJalling
author_rank: Unknown
timestamp: October 29, 2013, 09:56:30 am
content: Hi,I have just been offered a (used) Agilent 34401A for about 400 EUR incl shipping to DK. What do you guys think about the price? Is it ok?BR Jonas

author: KJDS
author_rank: Super Contributor
timestamp: October 29, 2013, 10:14:26 am
content: It's about right though possibly a little on the high side.I have the Keithley 2015THD which is also a 6.5 digit meter listed on ebay for £315 including UK shipping and to Denmark would only add another £20 at most. I'm also happy to offer a discount for any sale away from ebay.

author: iNoxxam
author_rank: Contributor
timestamp: October 29, 2013, 04:51:08 pm
content: Yeah, maybe a little too high. But not from afar. Whatever you won't regret that!

author: free_electron
author_rank: Super Contributor
timestamp: October 29, 2013, 05:26:15 pm
content: too high. 300$ tops...

author: KJDS
author_rank: Super Contributor
timestamp: October 29, 2013, 05:33:29 pm
content: Ebay completed listingshttp://www.ebay.co.uk/itm/HP-AGILENT-34401A-1000VDC-10mA-100mA-1A-3A-3HZ-300KHZ-DIGITAL-MULTIMETER-REFURB-/321217802114?pt=Desktop_PCs&hash=item4aca12af82$539http://www.ebay.co.uk/itm/HP-AGILENT-34401A-MULTIMETER-BENCH-6-5-DIGIT-DMM-/370900873829?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item565b6a3265&nma=true&si=Qk3NuxJdPhj%252BRlm5JDz4DMOfqhA%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557£429http://www.ebay.co.uk/itm/HP-AGILENT-34401A-MULTIMETER-BENCH-6-5-DIGIT-DMM-/290974849438?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item43bf73d99e&nma=true&si=Qk3NuxJdPhj%252BRlm5JDz4DMOfqhA%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557£343

author: senso
author_rank: Frequent Contributor
timestamp: October 29, 2013, 06:34:47 pm
content: Quote from: free_electron on October 29, 2013, 05:26:15 pmIn US it might be too expensive, in EU, pretty price, they usually go for 400-500€, or more, depending on how many bidders and if there is "advertising" of the selling.
Rigol RP3300 and RP2200 Probes - Page 1
Forum section: electronics / testgear

author: Electro Fan
author_rank: Super Contributor
timestamp: October 29, 2013, 06:23:53 am
content: Is there any reason to think that with a Rigol DS1104Z scope that a Rigol RP3300 probe would work as well, better than, or less well than a RP2200 probe? Thx

author: iNoxxam
author_rank: Contributor
timestamp: October 29, 2013, 04:49:52 pm
content: Hello,AFAIK, it should not matter. Both probes have higher bandwidth than your oscilloscope. You may notice a tiny difference in high frequencies but nothing that would make the measure unreleavant.Except that, maybe the build quality changes, but I have never seen a RP2200. For some reason I use a RP3500 (500MHz) probe instead of a RP3300 (300MHz) probe with my DS2072 (70MHz) and I prefer the RP3500 because it's handle is thicker and I got it better in hands, but except that, I dit never notice any differnce while doing measures.
Battery Corrosion Ate Plastic on Fluke 39 Power Meter. - Page 1
Forum section: electronics / testgear

author: cartertools
author_rank: Newbie
timestamp: October 30, 2013, 11:31:43 pm
content: First post on the forum...I bought three Fluke 39 Power Meters at the local university surplus sale today. All three had battery corrosion, two particularly bad with heaps of crust in the battery compartment. I spent time dissolving it all with vinegar and found that the plasic had actually been eaten into. I've never heard or read of such a thing and the only thing I can think of is that there was heat produced as the battery decomposed which allowed the plastic to melt into the corrosion. The rubber outer molding was not effected, interestingly enough. None of the corrosion effected the boards, etc either, it all stopped at the terminals.Two of the meters now work and I'll be getting some replacement terminals for the third (it had more of a rusty corrosion) and battery covers soon I hope.Anyone come across this sort of damage before?

author: PedroDaGr8
author_rank: Super Contributor
timestamp: October 30, 2013, 11:34:56 pm
content: Some thermoplastics are sensitive to highly caustic materials (a few others are very sensitive to highly basic materials). It's likely that the type of plastic used is of the caustic sensitive type (as alkaline batteries use a KOH solution). I had several reactions in the past that I had to source new clips for because the fumes from the reaction (highly basic if I remember correctly) caused the clips to become VERY brittle.
Rigol DS1104Z button query - Page 1
Forum section: electronics / testgear

author: santiniuk
author_rank: Contributor
timestamp: October 22, 2013, 11:03:02 am
content: Hi,I've just received the Rigol DS1104Z scope and quite an impressive unit. Not the greatest of spec but we have a lab full of equipment and I wanted something compact for my desk work.I have a question that I know has been asked but cannot seem to find on the forum. I sure someone mentioned that on the rigol scope the intensty knob was used on the menu selection to select a value and then you pressed the knob to select and exit. When doing this it often skips during the slight turn of the knob on pressing.Someone mentioned a button also worked as the 'enter' press but cannot seem to locate the post. Any idea what the button is to press ?Thanks

author: kizzap
author_rank: Unknown
timestamp: October 22, 2013, 01:26:37 pm
content: If you press the buttons on the side of the screen relative to the thing you want to modify it will cycle through the options.-kizzap

author: santiniuk
author_rank: Contributor
timestamp: October 22, 2013, 02:50:06 pm
content: Hi Kizzap, yes that's correct. I press the relative button and it cycles the list. It was the option to then select and exit from the list.I've now found the key. It's the up arrow pointer on the right hand side.Thanks

author: alank2
author_rank: Super Contributor
timestamp: October 25, 2013, 12:38:47 pm
content: What does your 1104Z go down to for the timebase? 5nS 2nS?

author: santiniuk
author_rank: Contributor
timestamp: October 28, 2013, 01:26:51 pm
content: Hi,Sorry for the delay, I was out of the office. Just checked unit and I can go down to 5.00nS(Just with a single trace.)Thanks

author: Deckert
author_rank: Regular Contributor
timestamp: October 28, 2013, 02:42:20 pm
content: Quote from: santiniuk on October 28, 2013, 01:26:51 pmHm... that's a bit disappointing. The DS1052E (50MHz) goes down to 5ns and the DS1102E (100MHz) goes down to 2ns. Even the Siglents go down to 2.5ns on 100MHz models.--deckert

author: alank2
author_rank: Super Contributor
timestamp: October 28, 2013, 02:43:21 pm
content: Quote from: santiniuk on October 28, 2013, 01:26:51 pmThanks for confirming that; I hope they go down to 2nS with a firmware update at some point.Alan

author: Deckert
author_rank: Regular Contributor
timestamp: October 29, 2013, 12:30:58 am
content: Quote from: alank2 on October 28, 2013, 02:43:21 pmnS = nano Siemensns = nano seconds?--deckert
Hameg HM 204-2 teardown - Page 1
Forum section: electronics / testgear

author: gis
author_rank: Contributor
timestamp: October 29, 2013, 11:56:36 pm
content: Hi,taking apart the just-arrived HM 204-2, I'm stucked with Y division concentric variators: how can I take them away without broken anything?Thanks for replies!
xfet voltage referances - Page 1
Forum section: electronics / testgear

author: johansen
author_rank: Super Contributor
timestamp: October 28, 2013, 08:57:52 pm
content: Does anyone know about this technology?http://www.mouser.com/ProductDetail/Analog-Devices/ADR4550ARZ/?qs=sGAEpiMZZMuBck1X%252b7j9fJ909qbP0fXHoNTGx6%2f1d5Q%3dexplained here:http://www.analog.com/library/analogdialogue/archives/32-1/xfet.html
Best oscilloscope sub-£300? Current offers? - Page 1
Forum section: electronics / testgear

author: 8086
author_rank: Super Contributor
timestamp: October 28, 2013, 07:50:35 pm
content: Looking for inside information from you guysAnyone know of any good offers or deals on sub-£300 scopes?Thanks

author: Carrington
author_rank: Super Contributor
timestamp: October 28, 2013, 08:06:35 pm
content: But what are you looking for exactly?- New, used?- Digital, analog?

author: 8086
author_rank: Super Contributor
timestamp: October 28, 2013, 08:10:46 pm
content: New, digital.

author: Carrington
author_rank: Super Contributor
timestamp: October 28, 2013, 08:16:14 pm
content: Then something like this: Voltcraft, Hantek, Tekway, Siglent or similar.I believe that all these brands have models for a similar price.Look in this topics:https://www.eevblog.com/forum/testgear/hantek-tekway-dso-hack-get-200mhz-bw-for-free/https://www.eevblog.com/forum/testgear/review-of-owon-sds7102/msg313606/#msg313606
Tektronix 2236 has a lazy channel - Page 1
Forum section: electronics / testgear

author: lnx64
author_rank: Regular Contributor
timestamp: October 26, 2013, 12:17:47 am
content: Not sure how to describe this, other than my 2236 Tektronix has a lazy channel, on channel B.Channel A works great, and has allowed me to do a lot of work and repairs on older retro game consoles. But channel B can't even show me a proper wave form for a TV scan line. Here, I'll show you what it's doing.Here's channel A. As you see, it looks fine:http://img.photobucket.com/albums/v395/Evilweredragon/channela.jpg~originalHowever, take a look at channel B, and you realize somethings not right here:http://img.photobucket.com/albums/v395/Evilweredragon/channelb.jpg~originalI've already taken it apart and didn't see anything obviously wrong, other than a loose vertical position knob for channel A, which I fixed.I have a feeling it needs deep repair on channel B. Channel A is definitely working all the way up to 100MHz like it should, but B won't reach 1MHz.Any ideas? Thanks!

author: AlfBaz
author_rank: Super Contributor
timestamp: October 26, 2013, 12:25:45 am
content: hmmm, sorry for asking the obvious but when using channel 2 do you select ch2 as the trigger?

author: lnx64
author_rank: Regular Contributor
timestamp: October 26, 2013, 12:36:53 am
content: Yes.In the pic it wasn't, but it does the same thing even when channel 2 IS set as the trigger.

author: oldway
author_rank: Super Contributor
timestamp: October 26, 2013, 06:54:06 am
content: Hallo,I think its more likely a defective input FET in B channel. (Q63)

author: sync
author_rank: Frequent Contributor
timestamp: October 26, 2013, 12:43:31 pm
content: Ch B is really lazyLooks like it lost a lot of it's bandwidth.Are positive and negative DC voltages measured correctly on Ch B?Do you have another oscilloscope?

author: lnx64
author_rank: Regular Contributor
timestamp: October 26, 2013, 03:10:42 pm
content: Quote from: sync on October 26, 2013, 12:43:31 pmOddly enough yes, voltages are measured fine. No other scope though.

author: sync
author_rank: Frequent Contributor
timestamp: October 28, 2013, 01:31:50 pm
content: Bummer. With a second scope you could feed a signal into both channels of the broken scope and compare the signals to isolate the fault.You can use the working channel A of your 2236 to trace the signal of the broken channel B. But no comparison of course. Use a square wave signal which is not displayed correctly. Get the service manual and follow the signal path of ch B.A warning. There are high voltages on the main board. Read the service manual about this and be careful.

author: oldway
author_rank: Super Contributor
timestamp: October 28, 2013, 04:32:05 pm
content: Why do'nt you change Q63 ? I'am 90% shure this solve the problem.This fet is a highly ESD sensitive device, be careful.
BK Precision slow  resistance  - Page 1
Forum section: electronics / testgear

author: oliver602
author_rank: Regular Contributor
timestamp: October 27, 2013, 07:18:15 pm
content: Hi,Got a BK Precision 2708B in October 2011 from Mouser after Dave's review and like it very much apart from the beeper.I noticed recently in resistance mode it takes a long time to settle. If I put the test leads together or plug in a short piece of test lead it will jump down to about 3ohms then get progressively slower as it approaches 0 (about a minute). If i jump from diode mode to resistance mode it does the same in reverse, It'll take about 5 seconds after auto ranging to show over limit. DC voltage works fine and compares spot on to my Fluke 87.Not sure what to do with it, can anybody offer some advice?Thanks

author: oliver602
author_rank: Regular Contributor
timestamp: October 28, 2013, 02:07:51 pm
content: Decided to battle customs and send it back under warranty.
Siglent 2013 Catalogue - Page 1
Forum section: electronics / testgear

author: Fay
author_rank: Contributor
timestamp: May 29, 2013, 09:32:15 am
content: Just received a updated catalogue from Siglent, however not covering the SDS2000 & SDS3000 which I most interested?To share with bros here in EEVBlog?O0

author: leandro
author_rank: Newbie
timestamp: May 30, 2013, 09:25:56 am
content: hi Fay, SDS2000 will be mass produced months later. Spec comes soon

author: Fay
author_rank: Contributor
timestamp: May 30, 2013, 09:47:35 am
content: Would you mind?

author: Siglent
author_rank: Regular Contributor
timestamp: July 05, 2013, 08:58:10 am
content: Quote from: Fay on May 29, 2013, 09:32:15 amThank you for your attention, We will release at an appropriate time

author: rf-loop
author_rank: Super Contributor
timestamp: October 28, 2013, 09:12:46 am
content: SDS2000 series datasheet(en).

author: Herman
author_rank: Contributor
timestamp: October 28, 2013, 09:35:06 am
content: Quote from: Fay on May 29, 2013, 09:32:15 amthe Chinese website of siglent has some information?but it is different to understand
Bench meter noise injection - Page 1
Forum section: electronics / testgear

author: Harvs
author_rank: Super Contributor
timestamp: October 28, 2013, 07:07:06 am
content: I lost about an hour yesterday trying to find the source of a truck load of noise on the ADC output of a new board I've just assembled.Turned out it was my bench meter I had monitoring the ADC input. It's an Escort 3146A, or probably more commonly known now as an Aglient 3402A.Attached is the scope captures of putting a banana to bnc converter on the meter, then coax to the scope. One is fed through a 50ohm terminator and the other with no termination.The large thin spikes I believe is the VFD, as you can pick them up just holding a probe near the front of the VFD.So, is this unusual? None of my handheld DMMs exhibit any noise injection into the DUT at all. Any idea what might be causing it? All looks about right inside, and the meter appears to work perfectly otherwise.
Testing reaction to power dips - Page 1
Forum section: electronics / testgear

author: logictom
author_rank: Unknown
timestamp: October 28, 2013, 03:12:32 pm
content: How do you go about testing a circuits reaction/ability to maintain functionality against power dips?We have a battery pack with a monitoring circuit attached which resets when a large load is connected, this was fixed by adding a big cap but I was wondering how you could methodically test for this?I did a quick search and found some test gearlinkfor this sort of thing but it's beyond budget.I was thinking of switching in a large resistive load but was curious what other methods are/can be used?Other than dummy loads are there any diy approaches that are usable?

author: grumpydoc
author_rank: Super Contributor
timestamp: October 28, 2013, 03:31:36 pm
content: With a variac.

author: nctnico
author_rank: Super Contributor
timestamp: October 28, 2013, 06:02:04 pm
content: Some HP power supplies can be set (HP calls this programming) to output a certain voltage based on a voltage. The PSU works more or less like a big amplifier. The extra device you need is a function generator. I guess other power supply makers offer similar features.

author: CodiJack
author_rank: Contributor
timestamp: October 28, 2013, 06:37:46 pm
content: You didn't mentioned about how much current you would like to load and what is the voltage.For a few hundred $ you can get electronic load (B&K, Chroma, ...) for a 30A load (on e.g. 10V)or about 300W total. Such load might easy simulate load dips.

author: KJDS
author_rank: Super Contributor
timestamp: October 28, 2013, 06:38:54 pm
content: There are a lot of interesting HP power supplies with fancy features, mostly called source meters.For mains, I've seen devices that remove every fifth cycle, and also used to use a huge valve amp with a simple function generator input that would enable testing from 70 to 500V at up to 30 amps from 44 to 500Hz. The room it was in didn't need any other heating and was unbearable through the summer.

author: logictom
author_rank: Unknown
timestamp: October 29, 2013, 09:34:20 am
content: Thanks for the feedback.Looking for a programmable supply/source meter type of device looks like it would be the best bet. I had been thinking in terms of pulling the actual battery pack low to cause the dip but it would be much easier to use a supply as the electronic loads I have been looking at for the high end case would have to be in the order of 2.5kW - dropping a spanner on the terminals would probably have been the easiest way to test thatBy using a variac do you mean to use it as a variable resistor? Bit lost there
DS2072 - what's this led for? - Page 1
Forum section: electronics / testgear

author: Circlotron
author_rank: Super Contributor
timestamp: October 27, 2013, 11:19:14 am
content: The led indicator above the multifunction knob - sometimes it comes on and if I shift a captured trace horizontally the trace disappears and I can't get it back. Have to power down scope to get led to go off. What is this led? See green arrow on pic.

author: Hydrawerk
author_rank: Super Contributor
timestamp: October 27, 2013, 02:16:52 pm
content: This led probably indicates that the multifunction knob is in use.

author: JDubU
author_rank: Frequent Contributor
timestamp: October 27, 2013, 03:17:33 pm
content: It means that turning the knob will change a menu selection or currently selected menu parameter value.When it is off, the knob is used to change the waveform trace brightness.If you want to turn the led off (go back to the knob's default, brightness control mode), collapse the current menu by pressing the "Menu" button.
Adding True RMS to Fluke 8840A and 8842A DMM - Page 1
Forum section: electronics / testgear

author: Attorney
author_rank: Regular Contributor
timestamp: October 27, 2013, 12:45:38 am
content: Anyone know if it's possible to add option AC-09 (True RMS) as a field-upgrade to the Fluke 8840A and 8842A DMM?Paul

author: PedroDaGr8
author_rank: Super Contributor
timestamp: October 27, 2013, 01:23:52 am
content: If I remember correctly it's an add-on card you add to the device. The cards tend to be hard to come by.Sent from my EVO 4G LTE using Tapatalk

author: sync
author_rank: Frequent Contributor
timestamp: October 27, 2013, 01:45:23 am
content: Yes, it's an add-on card. After installation the AC ranges must be calibrated.

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: October 27, 2013, 02:40:41 am
content: Hi,The AC boards are very slightly different between the 8840A and 8842A. If you search around you can modify them.Jay_Diddy_B
Tektronix 2225 - Page 1
Forum section: electronics / testgear

author: echen1024
author_rank: Super Contributor
timestamp: October 26, 2013, 02:51:23 pm
content: I have a chance to purchase a broken Tektronix 2225 for $40 + $33 shipping. Should I go for it? The seller says there is a broken vertical board, and he purchased a replacement but doesn't know how to install it.

author: sync
author_rank: Frequent Contributor
timestamp: October 26, 2013, 02:54:30 pm
content: Do you have the equipment to calibrate it? Look at the service manual what do you need.

author: echen1024
author_rank: Super Contributor
timestamp: October 26, 2013, 03:13:10 pm
content: Yes I do...

author: quarros
author_rank: Regular Contributor
timestamp: October 26, 2013, 03:48:58 pm
content: Quote from: echen1024 on October 26, 2013, 02:51:23 pmGo for it I say. I bought the same one for 130 USD (with shipping) and haven't regretted it. It is a good reliable piece of equipment. The biggest problem you will encounter is taking of the knobs, if it wasn't serviced lately. (I know mine was a pain to take apart)

author: sync
author_rank: Frequent Contributor
timestamp: October 26, 2013, 03:56:50 pm
content: Good. You should do a full adjustment after a board swap.But i don't think it's a good deal. I would not pay more than 20-25% of which i would pay for a working one. The 2225 is a very basic scope.And the replacement board could be damaged. IMHO 10-20$ with shipping would be ok.

author: echen1024
author_rank: Super Contributor
timestamp: October 26, 2013, 04:30:53 pm
content: Ok. So basically, the selling price is still a bit high? I know that 2225 prices have skyrocketed after Dave did a video on them.

author: sync
author_rank: Frequent Contributor
timestamp: October 26, 2013, 04:52:20 pm
content: Yes, the selling price is too high. It's broken. And I would place the 2225 a bit over the 20MHz <=50$ class. Why do you want a 2225?

author: echen1024
author_rank: Super Contributor
timestamp: October 26, 2013, 04:53:59 pm
content: I just wanted a cheap analog scope, and love old Tek gear.

author: sync
author_rank: Frequent Contributor
timestamp: October 26, 2013, 05:34:42 pm
content: Ok. Tektronix aren't usually cheap. But i would look for one with dual timebase. That's the main shortcoming of the 2225 IMHO.
HP 1640B Serial Data Analyzer Service Manual wanted - Page 1
Forum section: electronics / testgear

author: oldtvguymatt
author_rank: Contributor
timestamp: October 24, 2013, 08:24:53 pm
content: Hi all,I am currently working on one of these cool old HP Serial Data Analyzers, Basically it is a really cool serial breakout box with the ability yo monitor data lines and even do rudimentary serial device emulation.There is an issue with the vertical section of the display, it is not stable, it is locked but ever 2 or 3 seconds it shakes then goes back to normal. I have looked at the test points but without a service manual I am not sure what the waveforms are supposed to be.Does anyone have the service manual, schematics and BOM for this unit in PDF format.Thanks,Matt

author: dfmischler
author_rank: Frequent Contributor
timestamp: October 25, 2013, 01:27:00 am
content: The 1640B was the first serial data analyzer I used (I think 1981). Sorry, I couldn't find any references to the manual you want except onebay.

author: Mr Simpleton
author_rank: Unknown
timestamp: October 25, 2013, 10:08:55 am
content: You find most HP manuals and CLIP herer:http://artekmanuals.com/manuals/hp-manuals/Prices are very reasonable too! And very good service.Recommended
UT61E how can fix - Page 1
Forum section: electronics / testgear

author: user4963
author_rank: Newbie
timestamp: October 22, 2013, 07:50:47 pm
content: I am have problem. it wrong value measurement.this video:http://youtu.be/zaFsA8M0edICan we help you? please.

author: tom66
author_rank: Super Contributor
timestamp: October 22, 2013, 08:22:13 pm
content: I would clean the range switch, seen this caused by a dodgy range switch before.

author: mariush
author_rank: Super Contributor
timestamp: October 22, 2013, 08:27:49 pm
content: The first two (v and mv) are somewhat normal. The meter is sensitive and will show different measurements even when you move your hand over the probe tips or the holes for the probes. When you have the probes connected to actual circuit, the measurements will be fine.The resistance measurement is a bit strange, it shouldn't show that. Like tom says, open it up and check the selection wheel and buttons.

author: Legit-Design
author_rank: Frequent Contributor
timestamp: October 22, 2013, 10:29:41 pm
content: https://www.eevblog.com/forum/testgear/uni-t-ut61e-multimeter-teardown-photos/msg310594/#msg310594Quote from: user4963 on October 15, 2013, 06:29:11 pmQuite possible there is something providing high resistance path to add parallel resistance. 10K +-5% should be between 9.5k - 10.5k. It's either out of calibration or there is something little too much conducting on the path. Would some kind of flux residue cause that? Or flux residue with added water damage?Normal for cheap multimeters to show random numbers with nothing connected. For example Fluke 87V doesn't do that or atleast not as much, from what I have seen.

author: Unknown
author_rank: Unknown
timestamp: October 22, 2013, 11:36:29 pm
content: Quote from: Legit-Design on October 22, 2013, 10:29:41 pmYes, cheap multimeters like any decent bench meter ($800+) on the lower VDC ranges. This is mostly a function of input impedance. I don't think the 87V offers higher than 10 Mohm input impedance on any of the ranges, while the UT61E offers a much higher input impedance on the mV ranges.

author: retiredcaps
author_rank: Super Contributor
timestamp: October 25, 2013, 12:37:24 am
content: Quote from: alm on October 22, 2013, 11:36:29 pmThe manual for the 87 and 87 III says during power up, the mV provides > 4000 Mohm input impedance.The 87V manual just states "enables the meter's high impedance mode when the mV dc function is used."

author: Unknown
author_rank: Unknown
timestamp: October 25, 2013, 12:52:01 am
content: Only if you hold Hz during power up. If you turn on a UT-61E and an 87V normally and then set them to mV, the UT-61E will be in high impedance mode while the Fluke will be in 10 Mohm mode. So the value from the UT-61E will appear much more noisy. Has anyone compared the UT-61E with the Fluke 87V on high impedance mode with the same leads and lead position?

author: retiredcaps
author_rank: Super Contributor
timestamp: October 25, 2013, 01:26:49 am
content: Quote from: alm on October 25, 2013, 12:52:01 amYes, I forgot to mention my earlier post, it is a power on option.
Rigol DP832 Negative Voltages - Page 1
Forum section: electronics / testgear

author: Nilres
author_rank: Contributor
timestamp: October 24, 2013, 07:06:29 am
content: Hey everyone,I'm relatively new to electronics but I want to buy my first Lab-Power-Supply and think the Rigol DP832 is quite good for my tasks. But I have one question about it (or maybe about Power Supplies in general): The Rigol DP832 has two isolated outputs so I think I can connect those both together to get negative outputs (postive output to the GND of the other and then there is my new GND). But can I then still use the last not isolated 5V output on the devices?GreetsNils

author: quarros
author_rank: Regular Contributor
timestamp: October 24, 2013, 12:51:19 pm
content: You can use it. But remember that Chanel 3 has the same ground as Chanel 2 so if you are using it in a + / - configuration than the third channel can only create a maximum 5V positive voltage relative to the shared ground between CH2-3.

author: Unknown
author_rank: Unknown
timestamp: October 24, 2013, 12:57:35 pm
content: So connect the positive terminal of Ch1 to the negative terminal of Ch2 and 3. This is now your circuit ground. The negative terminal of Ch1 is then the negative rail, the positive terminal of Ch2 the positive rail and Ch3 is positive and referenced to the same ground.

author: Nilres
author_rank: Contributor
timestamp: October 24, 2013, 01:49:18 pm
content: Thanks for the clarification

author: os40la
author_rank: Regular Contributor
timestamp: October 24, 2013, 05:22:16 pm
content: I had asked the same question here.https://www.eevblog.com/forum/blog/eevblog-512-rigol-dp832-bad-design-investigation/msg301400/#msg301400FYI. If you are wondering if you can up the amps. This question has been asked and answered as well"Does anyone know if the DP832 can have its channels 1 & 2 wired in parallel to give 0-30v at up to 6 amps"https://www.eevblog.com/forum/blog/eevblog-512-rigol-dp832-bad-design-investigation/msg312216/#msg312216

author: olsenn
author_rank: Frequent Contributor
timestamp: October 24, 2013, 06:47:22 pm
content: You can get up to 6A by putting Ch. 1 and 2 in parallel. Up to 60V by placing Ch 1. and 2 in series.
Agilent 54642D - Page 1
Forum section: electronics / testgear

author: eurofox
author_rank: Unknown
timestamp: October 23, 2013, 01:51:13 pm
content: Hi guy'sI got today finaly my Agilent 54642D full options with new probes packed in sealed bags (analog + digital), all is virtually new.This scope is a mint+ with no trace of usage, virtually new.Got this all for 900$I loaded the lastest firmware without any problem.eurofox

author: Hydrawerk
author_rank: Super Contributor
timestamp: October 23, 2013, 09:48:32 pm
content: A nice scope from early 2000s.
Owon Line of Oscilloscopes - Page 1
Forum section: electronics / testgear

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: October 23, 2013, 01:59:26 pm
content: Does anyone have any experience with the brand. Good, Bad,

author: AndrejaKo
author_rank: Frequent Contributor
timestamp: October 23, 2013, 02:06:05 pm
content: Take a look at theHUGEtopic about them on the first page of this forum. It's called REVIEW - Owon SDS7102 - A look at the SDS series from Owon. You have pretty much everything that's known about SDS and newer series in that topic.If you want any specific information, then ask a specific question. I myself use SDS7102.

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: October 23, 2013, 02:24:05 pm
content: Thanks, yeah I saw that right after I posted. Good review!