EEVblog Electronics Community Forum
General => Buy/Sell/Wanted => Topic started by: Chris56000 on October 23, 2017, 01:14:54 pm
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Hi!
I have quite good experience in reverse engineering PCBs and I'd like to do the same for the Keithley 2002 DMM!
Has anyone got a "lame duck" Keithley 2002 they're willing to pass onto me for a reasonable price please - anything short of a major PCB burnup will do as long as I can see where tracks are (or were if burnt or eaten away!) - at this stage I'll be depopulating the PCBs completely to start work on the schematics so whatever faults there are don't matter!
Many thanks,
Chris Williams
PS! UK contributor preferred (I can collect) but if overseas please provide a suitable link so I can use PayPal!
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Are you a retired EE looking for a new fun challenge? :popcorn:
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Hi!
No I'm still in full-time Electronics Repair employment, with (possibly!) 12 years to go, but yes, I am looking for a mega-challenge in the shape of a "lame-duck" Ke 2002 to rev. whilst I've still got access to the SMD desoldering tools at work!
There's so many people on this Forum and elsewhere get stuck with these I feel a completed full set of drawings is needed sooner than later!
I appreciate it's a very big & long job but I've got cct. diagram software I can use very quickly now and half-a-dozen or so Sundays and a few evenings should enable me to complete the job!
What does make it quicker is there's a component-level parts list available already, so I'm not wasting time having to keep stopping to measure unmarked SMD, etc!
Chris Williams
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Might get a bit difficult, because people who have "lame-duck" K2002 want good K2002 and people with good K2002 don't give them away easily ;D
Anyway, before butchering a repairable K2002, I would try to find someone with fancy Xray gear, like this one:
https://www.youtube.com/watch?v=eECdoj8vkD8 (https://www.youtube.com/watch?v=eECdoj8vkD8)
A little less acceleration voltage, a bit more contrast and I bet you see the traces quite well, it's only 4 layer, IIRC.
And if you butcher a K2002, consider this video and find someone with good surface grinder (maybe me in the future ;D ;D):
https://www.youtube.com/watch?v=O8FQZIPkgZM (https://www.youtube.com/watch?v=O8FQZIPkgZM)
Then you can extract full PCB design and make replacement boards in case of epic meltdown
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Chris56000, this is an nice conquest.
I had a lame-duck Keithley 2002, but now it is repaired and Quacking like it should.
In the process I had to reverse engineer ohms and amps sections to a large degree. I used photographs with light going through the board with some post processing to see all 4 layers of the board. Photos were made from both sides and aligned to each other.
Examples are attached. I have more images like these, if you need them.
From my hand schematics TiN drew Ohms schematic. There is also DCI schematic available. https://www.eevblog.com/forum/repair/keithley-2002-repair-help/msg1319477/#msg1319477 (https://www.eevblog.com/forum/repair/keithley-2002-repair-help/msg1319477/#msg1319477)
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I used photographs with light going through the board with some post processing to see all 4 layers of the board. Photos were made from both sides and aligned to each other.
If you can post more information about it, it would be wonderful. Did you just drag the colored line by hand or used some automatic post processing SW?
May be this topic deserved a separated thread.
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This was all done by hand. When looking from top you can see top traces. Then internal traces show like shadows. More prominent and crispy of them are layer 2 traces. Then from photo of other side you can see bottom traces and layer 3 as prominent shadows.
The colors are: red - top, green - layer 2, blue - layer 3, yellow - bottom.
Traces and vias under components are much harder. Some I could see because I removed many microchips for cleaning. Others I had to guess and trace with continuity tracer. There is also many vias under resistors and capacitors.
For this task I had to photograph the board at very straight angle using a lens with minimal distortion. Then I massaged top and bottom photos more to align top and bottom exactly. This way I can point at something on top layer than hide it and see exactly what is underneath it on bottom layer. I also used my handheld microscope to peek under microchips at an angle in few cases to see the edge of what is going on under them.
In all it took many many hours to trace.
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