Octagon V2.0 column stopped working

[Charizard]

Hey guys, looking for some advice on how to fix this.  The other day an entire column on my Duck Octagon  v2  stopped working. Namely the Pause, backspace, \, enter, up arrow, down arrow column.

 I was looking at the back of the board, the problem column is circled in blue.  What I've done so far is testes touching pin A from the dead column pin B in another column, this gives nothing.  When I touch pin B from the dead column to pin A in another column, the key from the working column is registered as expected.  Wondering if there is an issue with power delivery to this particular column?  I'm not sure how to trace the PCB back to start diagnosing the source of the issue.


I don't think any of my solder joints are bad, and I don't think that would account for the entire column going dead.  Any and all help appreciated.

[suicidal_orange]

As this is a DIY board (I think?) you can cheat by looking in the firmware to see what should be connected to what, hopefully it's not a whole column and there's an easy fix (though your soldering looks good enough to handle the worst case )

On a proper screen it's clear the diodes connect across the rows and looking in the firmware there are only six rows so there's nothing funky going on.  The columns connect to multiplexers and conveniently it's visible - the yellow trace:



That is a strange place for it to break so I wonder as the screws are very shiny - did you just swap to screw in stabilisers?  If so you need something to insulate the screw that's shorting the empty switch pin (yellow square)  There's one touching some LED pads too (green square)

[Charizard]

I've been using the same screw in stabs since I assembled it a few years back.  That being said I'll unscrew them and double check nothing shorting there.

The yellow trace doesn't look broken and the pin on the mux looks okay too.  I do have a heat gun so perhaps I'll try reheating that surface mount if I can't find anything else.

Thanks for the advice I'll update here if I have any success.

[suicidal_orange]

Not likely to be that then, you probably have some washers already.

You can short your B pins to the chip leg to test for a break, it should type that key.  Maybe the pin in the chip just died...

[Charizard]

Great, I'll give that a try when I get a chance tonight.

[Charizard]

Just an update, the pin on the mux although looking okay must not have had good contact.  I blasted it with my heat gun and re-seated it using some tweezers and everything started working correctly.  Problem solved, thanks for the advice and healp!