[Help please!] Das keyboard clean + repair

[nmur]

Hey guys

I recently picked up this old Das with Cherry blues. The owner letting it go essentially for free (in return for a couple of caps) and lived very close to me so I went and grabbed it. He said that the numpad 6 key repeated a lot, and some of the keys needed a couple of tries to activate, and that these were likely caused by a liquid spill. I haven't done much repair/circuitry since uni so I thought this might be fun.

The board didn't come with caps, so right away I could see the shape it was in.



I tried a key test and it looks like every key activated just fine each time. However, the numpad 6 key did start spamming sporadically (not when I activated it), but I noticed that pressing Esc would actually cancel this spamming.



I took the case apart and took a peek. Pretty gross. You can see hair, rust, stains, etc. I cleaned it up a fair amount after this photo. Can't do much about that rust, and I don't care too much about restoring it too much until I can get it working.

More

Looking at the numpad area, I didn't see anything immediately wrong with the 6 key area.



A close up of the area near the ribbon cable. Pretty bad. Perhaps this is where the issue lies.



A couple of other damaged areas, but I can't say if they're related to the issue.




This is unfortunately as far as I have made it, and this is where I need help from you guys. I don't know enough about this sort of stuff to be able to find the cause of this issue. I have a soldering iron and a solder sucker on standby, and I can take any additional pictures if people request them.

Any help would be much appreciated!

edit: It's just occurred to me that it could be either the numpad 6 or the number row 6 being repeated. Both areas look fine though.

[XMIT]

The board still looks dirty. Continue to swab any dirty areas with isopropyl alcohol (91% or better if you can find it, most drug and grocery stores around here carry it) on a cotton swab/Q-tip. If you can use a lint free cloth that is even better. Focus on getting everything super clean first.

It looks like coffee or some other liquid was spilled into this keyboard at some point. There is a chance that the switches themselves are suspect. If you are able to desolder the 6^ and Numpad 6 switches and still see this issue that would isolate it to a shorted trace on the PCB. If not, solder back in one switch at a time and see what happens. How comfortable are you with desoldering through hole mount components?

[nmur]

The board still looks dirty. Continue to swab any dirty areas with isopropyl alcohol (91% or better if you can find it, most drug and grocery stores around here carry it) on a cotton swab/Q-tip. If you can use a lint free cloth that is even better. Focus on getting everything super clean first.

It looks like coffee or some other liquid was spilled into this keyboard at some point. There is a chance that the switches themselves are suspect. If you are able to desolder the 6^ and Numpad 6 switches and still see this issue that would isolate it to a shorted trace on the PCB. If not, solder back in one switch at a time and see what happens. How comfortable are you with desoldering through hole mount components?

woa someone replied (thank you)

I stopped updating this thread because I suspected a lack of interest. However, I did go and clean it up somewhat. I also determined that the issue was with the numpad 6, by shorting the switch pins to see if I got an activation. It didn't, so it seems the switch itself was probably fine, and it was an actual issue with the circuitry.

Playing with the issue again, it looked like the numpad 6 key itself didn't register, however if I pressed any other key on the same row, it would initiate the spamming of the numpad 6 key. Pretty weird.

Anyway, I didn't feel I could find and fix it myself, so I compromised. This board is actually intended as a xmas gift for my younger brother, who has been wanting a mech kb for 2 years or so now. I asked him if he uses the numpad on his current keyboard much and he told me he didn't, so I made a tiny autohotkey script that mapped the 6 key's input to nothing. With that running, the board works just fine, and looks decent with an old OEM keyset too.

A bit of a lazy "fix", but being a software engineer, I'm not surprised at the outcome....

[XMIT]

That's ... a disappointing fix.

I think cleaning the board as I proposed earlier will work wonders. It is certainly worth a shot. Anything that looks like fuzz, rust, etc. should simply not be on the board at all.

You can always direct your brother here, maybe we can help him fix it.

[trenzafeeds]

That's ... a disappointing fix.

I think cleaning the board as I proposed earlier will work wonders. It is certainly worth a shot. Anything that looks like fuzz, rust, etc. should simply not be on the board at all.

You can always direct your brother here, maybe we can help him fix it.

Agreed, you can't just give up! Agreed on the cleaning front, and you can always replace the switches that give you a hard time (although that's a bit more labour-intensive because you have to desolder everything). Hopefully you can direct the person you gift it to towards this thread, and maybe he will be willing to work it out.

[Homenubbie]

Desolder and replace 6 switch.