TNP #13 - Teardown & Repair of a Keithley 2001 7.5-Digit Multimeter

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Күн бұрын

In this episode Shahriar repairs a Keithley 2001 7.5 Digit multimeter. This is a very high performance unit and worth repairing. However, the early 90's revision of these units were subject to electrolytic capacitor failure all overt the analog and digital boards. The failed capacitors destroy the nearby traces including the inner layer connections. The teardown of the unit reveals this problem. By using x-ray imaging the missing and damaged traces are identified and meticulously repaired. Several of the power supply diodes were also destroyed. The repaired unit passes all self-tests as well as measured V/I/R in both DC and AC correctly. The unit is compared with measurements reported by a Keithley DMM7510.
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Пікірлер: 73

@WisdomVendor1 2 жыл бұрын

As an ancient electrical engineer that graduated back when the 8085 Intel processor was the bad boy on the block, I have to say that what you do on this channel is nothing less than amazing. Very enjoyable! Also, please give pooch a pat on the head for me.

@alimoradi2323 2 жыл бұрын

Hi شهریار Since these instruments are so sensitive it would be nice if you show the repair process. Trace recovering, components choose, any creativity during repairing. In the end, not only it's satisfying to see something broken comes back to life but knowing people won't let this stuff become junk and cause more pollution in our poor Earth is so nice. Keep the good work mate.

@OctavMandru 2 жыл бұрын

I was binge watching your work, and I have to praise you again for doing such high quality content while not being full time KZfaqr. Thank you, I would never dream to touch such expensive units

@estebansanches4236 2 жыл бұрын

Thank you, I learn a lot about troubleshooting with your videos

@djmips 2 жыл бұрын

Congratulations on fixing an old Keithley finally! Nicely done. That was a lot of fiddly work.

@TheGarrison89 2 жыл бұрын

This was amazing to watch, super informative and entertaining.

@jcudejko 3 ай бұрын

By the time you've gotten to 5:35 I'm massively impressed X-ray?? That is a method I've never considered

@yaghiyahbrenner8902 2 жыл бұрын

Shahriar - gerat work man!

@reallyniceaudio 2 жыл бұрын

I have a 2000 and a 2015. Both bought second hand and have the older type display. I was too scared to pull it apart to check the caps in case breathing on it messed the cal. After seeing what this went through I think I am safe to just pull the top off! Although not in CAL they both agree with each other very well but I need to be brave and check those caps!

@craxd1 Жыл бұрын

The great Capacitor Plague strikes again.

@buildstoys 2 жыл бұрын

Awesome, love the repair videos!

@dencolo 2 жыл бұрын

You are an artist ..

@andymouse 2 жыл бұрын

Great work...cheers.

@JLCPCB 2 жыл бұрын

Great work! 😉

@RyanUptonInnovator 2 жыл бұрын

Very good video.

@SalvagedCircuitry 2 жыл бұрын

Awesome job Shahriar! You are making me frantically search ebay for xray machines :D

@cosmolittle1395 2 жыл бұрын

Regarding leaking components, there was nothing worse than the NiCad RAM backup batteries sold in the 90s for PCB mounting. They ALWAYS leaked electrolyte onto the board, which rapidly destroyed the tracks. Thankfully we now have flash memories and EEPROMs.

@keithlambell1970 2 жыл бұрын

Gah. The curse of the electrolytic capacitor! And they were a good make too. Amazing work.

@xDevscom_EE 2 жыл бұрын

Ha, fixed like ten of these :D My first precision project ;) uh oh, BNC connections for DC voltages, volt-nuts angry :) Now you need xDevs calibration.

@Thesignalpath 2 жыл бұрын

You have done some great work analyzing these units. Thanks for that.

@xDevscom_EE 2 жыл бұрын

@@Thesignalpath 2001 was my entrance to rabbit hole, I got first one in 2009 year and was reverse engineering it to figure out how all worked inside. Took a while, but 2001 is great learning tool for analog design. Also bigger brother 2002 shares many design features and I love them for compactness.

@kenchilton 2 жыл бұрын

Nichicon PR series was notorious for these leaks. Every component maker seems to have their bad period, and this was Nichicon’s. All of this seemed to be fixed when RoHS hit. If your equipment has non-RoHS Nichicon capacitors in it, it is worthy of recap now - a small price to offset a big risk to expensive equipment. I will guess that any of the 2000 series Keithleys will fall into this PR series cap era, so please check them.

@xDevscom_EE 2 жыл бұрын

2001's usually have VX series. It might not be only issue of cap itself but also that in 2001\2002 these caps used in boost drive to generate front end floating +\-38V, and have large currents swings when go bad. Also very close placement next to hot LDO regulators kill caps faster.

@kenchilton 2 жыл бұрын

@@xDevscom_EE There was also the capacitor plague in that era for all those using off-brands. The late 90s and early 2000s were rocky for capacitor quality. I also had a lot of issues with electrolytics in the early 90s for other reasons, but those surely have all failed by now. My latest problem is with all these knock-offs. It was hard enough finding supply, but even usually reliable suppliers were getting duped for a while there, and caps were some of the targets. I open the cover on one fairly new terminal and see the cap is in pieces - so I have to recap all of them. I would never have guessed we would spend so much time on basic components like this.

@sbelectronicaindustrial6652 2 жыл бұрын

Hi....Very good video about this multimeter... Kind regards...!!

@thebood4553 2 жыл бұрын

Thank You VERY much Shahriar! I checked my 2001 and it also had the Nichicon caps. They aren't leaking yet, but one is not flush to the board at an angle, so its starting. You are the best ???? Paul

@thebood4553 2 жыл бұрын

oops, I meant 'you are the best !!!'

@SidneyCritic 2 жыл бұрын

RMC repaired a Pioneer LaserActive from the mid 90s, and it was full of Nichicon caps that had failed. It felt like there was over 100 caps - lol -.

@sirousmohseni4 2 жыл бұрын

Good video. Thansk for sharing.

@McTroyd 2 жыл бұрын

Thanks for doing videos like this, Shahriar. I realize it's always a risk buying broken and trying to fix, but that's likely the best route for a home hobbyist like me, to afford a 7.5-digit meter of this caliber. Maybe buy two and hope there's enough parts to make one work? 🤷‍♂️👍️

@Bianchi77 2 жыл бұрын

Nice video, thanks for sharing :)

@supernumex 2 жыл бұрын

Lab tour please, especially desks, shelf etc.!

@GaRbAllZ 2 жыл бұрын

Wouldn't it be great if the manufactures would protect the board around all caps with a coating (or even tape) that is resistant to the dielectric that leaks out of caps?

@pa4tim 2 жыл бұрын

In the 90s there was some sort of problem with electrolytics. The problem was that the formula stolen from Japanese company was incomplete and now millions of electrolytic capacitors with a "terrible" water-based electrolyte have flooded the world. There is a paper talking about it by V.I. Gurevich called: ELECTROLYTIC CAPACITORS: DESIGN FEATURES AND PROBLEMS OF THE CHOICE

@stazeII 2 жыл бұрын

Thanks for this! I keep hunting for one of these 2001’s as an upgrade to my old 6.5 digit Keith my 196’s, but hearing they’re a pain go repair gives me a bit of pause.

@thefinalmovements80 2 жыл бұрын

Awesome vedio sir love from India.

@feedback-loop 2 жыл бұрын

nice meter

@navadeep.ganesh 2 жыл бұрын

@shahriar says It's quite consistent, damage is significant! After a while -- Fix done ✔️✔️

@InssiAjaton 2 жыл бұрын

Thanks for the hint! I need to check my Keithley 2000 before it develops the same issue. So far it has not had any problems, but on the other hand, it has seen almost zero use since I got my Agilent 34411A (for its higher speed). I don't have anything beyond 6.5 digits, unless I would count the HP 3457A that supposedly would provide 7.5 digits if I would read the relevant internal register through a computer hook-up. Its display is 6.5 digits. And of course it is more than 40 years past calibration due date...

@BB-me9po 2 жыл бұрын

Shahriar - It would be interesting if you could somehow get your hands on and review the new Mini-Circuits eVNA-63+ 6GHz USB-based VNA sometime. Just a thought... Fantastic channel, BTW, from a long-time subscriber!

@bansci 2 жыл бұрын

Another great repair! I really want an X-ray... I wonder why they introduced diodes to protect against failure but didn't change capacitor series to prevent failure? Or did they change it?

@johanneslinde4437 2 жыл бұрын

I have a Keithley 2000 that is somewhat faulty. Last time it was powered on (several years ago) , it reported several errors during self test but worked OK on most modes and ranges (mind you, I do not have a standard to compare it to) . A visible inspection of the board and capacitors did not reveal any signs of damage. As you suggest, it sounds like they should be replaced ASAP. I read an eevblog post, where the relays were the culprit of some of the errors I experienced but I never got around to replace them. I also read on xDevs (iirc) that the main switch tends to fail so I guess there are more common issues than just the capacitors alone. What capacitor types did you end up replacing in your Keithley 2001? Great video anyways, thanks for the inspiration to try to fix the Keithley 2000.

@vincei4252 2 жыл бұрын

Good job. I have a 22GHz Tektronix spectrum analyzer that was delivered to me with a pack of electrolytic caps. It's of similar vintage to this Keithley so I dread to think what's going on in there when I open it fully.

@SylwerDragon 2 жыл бұрын

Hello. Nice video. I had the 'honor' to work on same model ..it was pain in the butt..it is fine if you know what is clearly wrong..but if it isn't clear and you have to remove board all the time..pain in the butt. who designed this assembly process shouldn't be let work for them anymore.. because if you want to remove the board you have to remove almost all components ..once you start it ..you have to heatsink that white resistor that is on side..( i didn't notice it was getting hot) ..also that black cover is really pain to work with ..because those wires are pretty short and those beads are hard to put in place once cover is there..really nightmare..

@paulpaulzadeh6172 2 жыл бұрын

Nice , whish you show whole lab too , go through all equipment, solder station, bench

@TheDefpom 2 жыл бұрын

Nice, I’ve been keeping my eyes open for a faulty unit too but the price was always silly considering the risk of it not being repairable.

@KD0CAC 2 жыл бұрын

Would like to have watched the trace repairs ? Thanks again

@inse001 2 жыл бұрын

Alarmed by this video, I went down to my workshop to check my beloved 2000 for any signs of leakage. Mine seems to be from ~’99 and the electrolytics look fine.

@video99couk 2 жыл бұрын

Oh right! Mine works but I'll take it apart and replace those PSU capacitors before I use it again.

@KA6WKE 2 жыл бұрын

I'm pretty sure the date for these caps is about the same timeframe when there were motherboard failures due to bad caps.

@tamaseduard5145 2 жыл бұрын

🙏👍🙏

@iamgodlewski 2 жыл бұрын

Forgive me for asking this, but what are the real world use cases for needing 7.5 digit multimeter accuracy? I've always wondered, seeing as the price jump to 7.5 digits is steep when 6.5 digits accuracy is pretty good already.

@Thesignalpath 2 жыл бұрын

Please keep in mind that accuracy, precision and resolution are all different things. Having a 7.5-Digit meter gives you the resolution to look at a very small change in value in the presence of a much larger value. For example if you are measuring 100V and want to see a difference of 1nV. When a meter is built at higher resolution, they also improve its accuracy and precision at the same time (otherwise the resolution would be mostly wasted).

@juliand1053 2 жыл бұрын

7.5 digit DMMs are used for calibration.

@TheFool2cool 2 жыл бұрын

@@Thesignalpath can you give an example of when you would want to look at 1nv change in 100mv? Im always curious about what goes on in some labs

@pa4tim 2 жыл бұрын

I use a 7,5 digit (Keithley 7510) for repairing measurement and calibration gear. Besides that, it is lightning fast. I have a Prema but it takes many seconds for a 7,5 digit reading, that makes it useless for aligning f.i. a Vref.

@patnutoris4054 2 жыл бұрын

My use case was to determine drift in lasers (VCSEL) over time for quality control reasons.

@MartinPHE 2 жыл бұрын

wow

@carllovitt2912 Жыл бұрын

Hello - Great video! I'm wondering what the cable is that you're using to sync the 2001 to the 7510 is? I can see that it's an HP part but cant' see the part number. I think I lose some accuracy of measurements with less than ideal cabling. But maybe not - I'm a software engineer of 30 years that wants to be an EE and repair amateur radio's for a living so I don't know what I don't know lol. It might be a good segment to talk about cables in general (N vs BNC, cable types etc.)

@derwhalfisch 2 жыл бұрын

Can I ask, where should i look for suggestions on what to check in my Keithley 2700? It works great but it's clearly old and I don't know which forums etc to explore

@Homer19521 2 жыл бұрын

Jerk.* Got your own xray??? Spoilt brat. * Highest compliment I give. ;-)

@rolfdieterklein Жыл бұрын

Great video - Just got a 2001M Version with B16 A02 Firmware -- anybody knows about this release - cannot find infos in the internet on this, maybe open up it later but I still got garantee for some month so have to wait -- then hope the caps are of the newer versions ...the seller ony made a cal zertificate not looking inside.

@Drew-Dastardly Жыл бұрын

2001M is the most documented version - it is the military version and so just like the HP 3458A had to have all schematics and service information released by US law. It's funny, this was normal just for regular people with a TV set or Radio back in the '80s, but the US Government had to force manufacturers to give service information for "free" if they wanted a $1x billion+ contract for military procurement. Just so their techs in a warzone didn't have to rely on shitty corporate service like Applecare or John Deere. You will find all the service manuals for 2001M on xdevs. I've a couple of 2001M and they are all 2008 vintage and from the US Navy. Very low mileage, brilliant VFD displays, and all the capacitors are not from the '90s plague they are all good. Tested visually and with a DER EE-5000. The hysteria about replacing the caps without sight, without testing, doesn't apply to these later 2001M's for sure.

@marvintpandroid2213 2 жыл бұрын

Could they be fake caps?

@chuxxsss 2 жыл бұрын

Resistors? word at start.

@jonathanjones6657 2 жыл бұрын

The AMC Gremlin was released on April 1, 1970. AMC advertised it saying “competitors will find there is nothing ‘April Fool like’ about this car.”

@jaa93997 2 жыл бұрын

you mean, of course, a FUUUUUULLLLLL BRIIIIIIIDGEEEEEE RECTIFIIIIIIIERRRRRRRR

@HeyBirt 2 жыл бұрын

I have never been impressed with how Kiethly gear is made. Some of them are horrible and the best of them are mediocre. They do work but when they break, they are a pain to work on.