No.133 - Keithley 2001 7.5 Digit DMM Repair (re-upload condensed)

Back in 2022 I published a 6-part series of videos for the repair of this Keithley 2001 DMM.
It was quite a repair, highly enjoyable on my part, so I thought I'd re-upload as a single ~1hr condensed video.
Enjoy!
PS. This video is HD only.
#electronicscreators
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[@onesandzeros]

Thanks Ian, I remember parts of this but probably didn't see all 6 videos. Great work and great editing!

[@somewaresim]

Wow what a marathon. Glad to see how much you enjoy it.

[@bobsoft]

Cant get over how much you sound like Jackie Stewart

[@joelkist6493]

Watched her from beginning to end again... nice job!

[@robjordan63]

Fantastic fault diagnosis, what an epic!

[@bertoid]

Great video Ian! I admire your determination, perseverance and skills. I think I would have given up when/if I suspected the CPU had blown. And lucky you had a donor analog board - fixing the original would be a nightmare if many chips were blown. I'm amazed that they designed a unit whereby the failure of a relay or its control circuitry could catastrophically blow the arse out of the entire instrument!

[@IanScottJohnston]

I think it is one of those designs where the design dept. thought they had created something great…….but nobody said “what if”!

[@brendanbarbour8568]

It’s so often ones eyes and nose that can provide the vital leads you need to track down problems. I worked with a guy a long time ago who would insist on going over a faulty PCB with a jewels’ loop before doing anything else..he had a great hit rate…better than me for sure..!!!

[@IanScottJohnston]

Yep, everyone has their own methods depending on their life journey in electronics. Also depends on whether you own it or it's a customers LOL!

[@robharley9838]

Incredible Ian, well done! Don't think I've ever seen such a catastrophic cascade failure through so many ICs. Amazing to this Bodger that you're able to repair such a disaster. Really enjoy your work, thank you! - jrh

[@IanScottJohnston]

Cheers!

[@skylabby]

Another great repair.. I always enjoy them, need to see some hold HP Spectrum analyzer repairs ...

[@andymouse]

Awesome !.....cheers.

[@jeditoto3441]

Great video Could show how reprogram chips?

[@2sc458]

Was the thing hit by lightning?

[@TheEmbeddedHobbyist]

what like Campbell's condensed soup. I grew up with a liking for condensed tomato soup.

[@DrFrank-xj9bc]

Well, not only gloves, but also an ESD bracelet is required, I guess 🤭 Anyway, HP had much better electrical engineers than KEI. Such a complicated, convoluted schematic, for the power supply, and for other parts. This is a nice compressed version of your repair session - ver y entertaining, again.

[@jeditoto3441]

Any idea why the made it so complex?

[@davidv1289]

I really enjoyed the original series - I learn so much from the detailed troubleshooting. I also enjoyed this condensed "revisit", thank you Ian. The automatic mains voltage selection feature seems like a really bad idea, can't really be designed to be fail-safe. Also seems unnecessary - how often does the input voltage need to be changed? Regards, David

[@IanScottJohnston]

The worst of the design is that, certainly for 240VAC countries, when it goes wrong it can do little else but fry your Pcb's!

[@braddr1]

@@IanScottJohnston Yeah, that part of the circuit is just overengineered, imho. It could have been the much simpler mechanical system that more or less never fails. I've collected a number of parts + broken systems to work on repairing. So far, haven't fixed any, but in fairness, also haven't spent much time on the project. :)

[@stevehurcombe]

​@@IanScottJohnston do you think it's worth modding the circuit to hard-fix the voltage selection?

[@eded8045]

did I miss that you never replaced that mains inline filter?

[@IanScottJohnston]

No, I don't think I did. The supplied ones looked fine.

[@eded8045]

@@IanScottJohnston have you seen how nasty they treat the inside when they blow? I would change it they do suddenly go shame all the effort and new parts

[@eded8045]

you need some russian donations from an era to make a spicy videos

[@eded8045]

sometimes i wonder if for sake of content you guys make a mess of a PCB to then show horror and repair it just some humor!

[@IanScottJohnston]

You might be right!.......but certainly not from me. LOL!

[@eded8045]

@@IanScottJohnston youre too straightforward as a Scott you couldn't do that

[@feedback-loop]

Ian, I do appreciate your content very much, but so many "let's go ahead and ...", "I went ahead and ...", "I have gone ahead and ..." and such

[@IanScottJohnston]

Remember, this video is a 6-part series condensed down to ~1hr. Also, it's not my style to show everything, every solder joint, every nut and bolt, every re-wire the test setup.......because people just complain that "we know how to replace a capacitor" especially after so many videos. Also, sometimes off camera we find things and try things without the camera running and it's not so easy to roll it back just to film......if we did our videos would take MUCH longer. I try just to show what I think is the interesting stuff.

[@feedback-loop]

​@@IanScottJohnston It seems like you are replying to somebody else. I was talking about the overuse of variations of "go ahead and (do something)" filler phrase

[@IanScottJohnston]

@@feedback-loop That's what I thought you were meaning, in general......so my apologies! Hmm, maybe it's just the Scottish way of talking, at 59 it will be hard for me to change......LOL. No worries!....PS. Love your channel.

[@andymouse]

@@IanScottJohnston Poor we Jock's heid all a bother noo !.......squeak

[@IanScottJohnston]

Naw, ye learn to be thick skinned in this game...LOL!