Come on a ride as Dave repairs an intermittent Keithley 177 Microvolt DMM, garden paths and all.
Service manual & Schematic: http://www.utwente.nl/tnw/slt/doc/apparatuur/multimeters/keithley177.pdf
Datasheet: http://www.datasheets.pl/integrated_circuits/I/ICL/ICL71C03.pdf
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Forum: http://www.eevblog.com/forum/blog/eevblog-777-keithley-177-microvolt-dmm-repair/msg725852/'>http://www.eevblog.com/forum/blog/eevblog-777-keithley-177-microvolt-dmm-repair/msg725852/ #msg725852
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Service manual & Schematic: http://www.utwente.nl/tnw/slt/doc/apparatuur/multimeters/keithley177.pdf
Datasheet: http://www.datasheets.pl/integrated_circuits/I/ICL/ICL71C03.pdf
555 Timer T-Shirt:
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Negative Feedback T-Shirt in the EU:
https://fabrily.com/negativefeedback
Forum: http://www.eevblog.com/forum/blog/eevblog-777-keithley-177-microvolt-dmm-repair/msg725852/'>http://www.eevblog.com/forum/blog/eevblog-777-keithley-177-microvolt-dmm-repair/msg725852/ #msg725852
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Done.
Just change the bloody resistor before you check anymore -_-
We don't all speak like that in the US, lol.
Love the channel
A 30kv discharge may have ionised the socket terminal connectors in the instrument
At the 7 min part it appears to be a faulty red and/or black terminal connection fault
I've had this loads of times with old scopes, given the information you received with this I would have opened her up straight away aswel, voltages, silicon, flex the board, poke around, re-seat the ICs and so on 🤷♂️.. sometimes its better with no prior information 😅 as soon as I saw the A/D was working I knew you would get it going, bit of a surprise to see the separate integrator ic like that.. good video anyway mate 😎👍 hope it found a good home to live out its twilight years
Just started watching, …bet it's the MUX ??? …waiting for egg on face :):)
I learn from every video you make. Old or new. Whether it jump at you or not. Because that is real life. Thanks for all you do. keep up the great work.
clean switches.. Blue stuff if you have it, polishes too.
GREAT VIDEOS! from a 45+ year component level technician with 48 certifications and vice president of CESDA (sub of NESDA) in 1980- 1983!!
I assumed this video was dragged out just to make an interesting video.
Just a note to say there is a difference between how a wizard like Dave works and a dumber yet experienced repair person. Any of us experienced repairers would have instantly zeroed in on those switches. It was my first thought (Like many looking through the comments).
We can often glance at something and tell the person whats most likely wrong without even picking up a screwdriver – I'd say in 90% of cases we are correct too.
Not being bigheaded ..much..😸but this one was obvious.
I often think its rather like being streetsmart… You know the dumb kid who still gets your wallet even though you are a brain surgeon.
Your comment as an electronic engineer "ah, bloody mechanical crap" contrast well with my occasional comment, as a mech engineer, "ah, bloody electronics crap" 🙂
To get contact cleaner into those switches, spray contact cleaner into the openings at the end of the switches. Those switches sometimes had silver plated pins that oxidize with time making poor contact.
The banana peel is too close to the DUT.
The burned out resistor & diode nerver got replaced?
My electronics teacher always said , make sure its plugged in.. Ya the simple things 1st.
The path for the fluid is through the end of the switch. Turn the unit on it’s face and squirt down the end of the switch. Obvious!
Yeah, let all the dirty contact cleaner and all the washed out gunk go down into your DC voltage source.
Don’t make excuses, you just missed the obvious. I have seen you do that before…… 35 years old, all the more reason to check the switches.
Hi. You're supposed to spray the contact cleaner in from the rear of the switches, not the top, while operating them. Remember: you have to wait until it's dry as a dead dingo's donger, before you turn it on again.
I just fixed my 179A which had the same fault. If you turn the unit so the front is facing down you will notice your can squirt down a whole in the back of the switch! I then did a transfer cal from my 2015 and have managed to get it to match perfectly. I am so pleased with it it has replaced my silly isotech idm 203 as the screen on the 179A is amazing!!