how to debug/fix keyboard ESD damage?

[Special K]

I touched my keyboard's spacebar and section of case just below it this morning and heard/felt a pop from ESD.  I ran the keyboard tester on this page: https://www.keyboardtester.com/ and the following keys don't work: 

Code: [Select]

F3
F7
backspace
tab
t
y
{}
caps lock
left shift
4,5,6 (numpad)
Is there anything I can to debug and fix this issue?  The keyboard is a full-size Filco so I'd rather not just throw it out and buy another one unless absolutely necessary.  I'm not even sure how this happened given that the keyboard's case and keycaps are plastic.  Has anyone ever had this happen before?

[suicidal_orange]

Usually shock damage happens with custom aluminium cases but those keys are all in one 'row' in the Filco switch matrix so it sounds like you have indeed killed a pin on the controller.  The plate which holds the switches in is metal and it's not far below a pressed spacebar...

The good news is Filco make boards with controller chips that slot in with no soldering* and as we geeks like to be able to remap our keys bpiphany makes replacements - website or if you live in the USA it would be quicker to buy one from 1upkeyboards.  I'm assuming it's a Majestouch, if not and you can't work out which you need post the board name and pics in the thread and he'll confirm.

*you'll need to unscrew/unclip the plastic casing to see the controller so bye-bye warranty

[Special K]

those keys are all in one 'row' in the Filco switch matrix so it sounds like you have indeed killed a pin on the controller.

Thanks, I was able to find this page which confirms what you said:

https://deskthority.net/wiki/Controller_matrix_traces#Pinout_and_matrix

The plate which holds the switches in is metal and it's not far below a pressed spacebar.

So the plastic of the spacebar is apparently not enough of an insulator to prevent static discharge to the metal plate underneath?

The good news is Filco make boards with controller chips that slot in with no soldering* and as we geeks like to be able to remap our keys bpiphany makes replacements - website or if you live in the USA it would be quicker to buy one from 1upkeyboards.  I'm assuming it's a Majestouch, if not and you can't work out which you need post the board name and pics in the thread and he'll confirm.

*you'll need to unscrew/unclip the plastic casing to see the controller so bye-bye warranty

Thanks for the advice.  The board is 5 years old and I had already taken it apart to try and debug the issue, so no problems on the warranty.  I'm glad none of the diodes are bad (I think?), as they are soldered to the back side of the PCB and accessing them looks like it would require unsoldering all of the switches to separate the PCB from the metal backplate.

[suicidal_orange]

Pretty sure the plate is painted too so that should insulate it.  Doesn't matter what the theory says though - you felt the discharge and now it's dead, life doesn't always obey the rules.

If you have a multimeter or continuity tester you could check between the pins in the controller socket (press a dead key, tester beeps) but diodes are tough and I can't remember helping anyone who killed one so they're probably fine.

I did a switch swap on a Filco and it was not terrible to desolder, though it does take a while as there are a lot of keys so hopefully you wont have to.

[Special K]

The good news is Filco make boards with controller chips that slot in with no soldering* and as we geeks like to be able to remap our keys bpiphany makes replacements - website or if you live in the USA it would be quicker to buy one from 1upkeyboards.  I'm assuming it's a Majestouch, if not and you can't work out which you need post the board name and pics in the thread and he'll confirm.

Is it possible to buy an original Filco controller board anywhere if we don't need the programmability of the aftermarket controller boards?  I'm not finding any for sale through a Google search.

[suicidal_orange]

Probably not, you could ask somewhere that sells Filco boards as they would have contacts. 

[Special K]

Unfortunately none of the Filco vendors, nor Filco themselves, would sell me a replacement board.  I bought a Tiger Lily controller from 1upkeyboards and it seems to be working, although there were some glitches in the first minute or two after I plugged it in (keyboard would randomly stop responding completely, shift key would register as being held down when it wasn't); hopefully that's just a temporary thing.

[suicidal_orange]

Why would they - the board lasted 5 years and you like it enough to try and fix it so chances are you'll buy another and they make more money without the hassle of stock management for parts.  Sad but true of most companies...

Glad to hear it now works, lots of people use bpiphany's controllers and they use the same chip as most custom keyboards so it shouldn't give you any problems.  If the strangeness returns check the cable inside isn't slightly caught beneath a switch pin as a short there can cause anything to happen.  Doesn't sound like it is though as the problem should be constant.