[Help] How do you guys trace a keyboard PCB that has diodes?

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09 Jan 2019, 04:11

I usually poke around with a multimeter in continuity mode. Is there a technique I should be using?

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09 Jan 2019, 04:57

What I've typically done is hold one of the multimeter probes on the leg of the diode leading to the controller components, instead of the switch terminal - that way can still use the continuity testing mode with the beep, rather than having to worry about the polarity and watching the multimeter screen.

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09 Jan 2019, 04:59

That's pretty much what I do, and I've surely done less of it!

I think the general rules are:
  • Find the pins on controller leading to the matrix
  • Figure out which of those are rows and columns
  • Follow as much by eye as you can, and use the beeper as your sixth sense
  • Draw a grid, label the columns and the rows, and populate the bugger one key at a time
  • And do what Oldie says: keep the diodes out of it, bypassing them when dealing with those pins
I'd like to think there's a better way. Anyone?

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12 Jan 2019, 03:44

I figured something out!!!

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