need help fixing K95 platinum

[_mooman_]

Hi, My K95 Platinum (with the usb passthrough) sat in a desk for last 18 months as I used a chromebook remotely (ick). I'm 99.9% sure no one messed with it at the office as it was locked in my desk.  It no longer works with the following keys dead (used passmark key tester):

ESC LEFTCTRL SPACEBAR , . F4 4 r f c

switches are all good (tested with multimeter).

Pulled everything off the keyboard PCB (LED strip, audio roller, 3keys (labelled BCD in manual)and then ran KB PCB though my ultra sonic cleaner. Let it dry for a long while, and has same problem (didn't bother reconnecting the other PCBS to avoid more problems)

I'm guessing somehow one of the matrix cables has gone bad, but reseating them does not fix it.

I don't have the schematic for the K95 and didn't test the diodes in circuit.

Any ideas?  I'd hate to trash a $200 keyboard and I really liked G1-G6!

Thanks for any hints.

[suicidal_orange]

Matrix cables?  Pictures definitely needed

[_mooman_]

I let the main part of the k95 sit in warm 99% alcohol for a while, then dried well. The ESC key works most of the time now, but I can't do the keyboard reset. No matter how long I keep ESC pressed, I don't get the flash as the manual says I should. Instead, releasing ESC immediately sends the keyboard into a repeating rainbow pattern on all LEDS. I previously had them set to all white for a simple backlight. Is the rainbow puke the normal power up colorset?

I'll try and get pics this weekend.

[fomby]

I have a non-platinum K95 and IIRC the rainbow spiral is the default on a new keyboard as well as in iCUE.

[Topweasel]

Didn't see anyone reply so I thought I would throw some info out and suggest a few things.

1. There isn't a Matrix cable. There is a matrix of traces on the PCB and this would apply whether it was a mechanical or membrane keyboard.
2. I bring up Membrane because they zone their keys to prevent issues with roll-over (only one key can be active on any one zone). And the randomness of the ones not working would suggest a zone on a membrane. The fact that its a MX based mechanical makes the randomness a little weird. They tend not to have weird matrixes because with the diodes they can have NKRO without any effort on the matrix.
3. You do have one nearly solid line with the F4 down to the spacebar. So its possible that that there is an interruption there.
4. My first guess would be that there is a broken solder point specially somewhere in the f4-space. Just because those are connected. Might be smart if you have a soldering iron to reflow the solder for those switches.
5. Have you brought up a keyboard tester and seen if any keys are being triggered? I wish there was a good way to see if FN is triggered. Specially with esc bringing up a lighting setting makes me think that you are accessing a function layer where only those few keys mean something else so the rest type normally.
6. Becareful opening up. Corsair uses a million screws and tabs on the case. Even when doing everything correctly you might still lose a tab or two.