Repairing an ibm model m2/selectric touch?

[nickg]

"The electrolytic capacitors in the logic board are prone to failure" - the wiki

While mine seems to be working just fine right now, I'd like to sort of know how to fix everything just to be safe.

https://www.youtube.com/watch?v=K_W33djliV0

I found that video, and it looks ok but before I order the capacitors etc it says to use, cam anyone that has repaired one before confirm if that is a good guide to use?

[swampangel]

Here is another discussion on geekhack https://geekhack.org/index.php?topic=50420.0

I repaired one of mine using the values specified there. I believe I ended up using 1 ceramic and 1 electrolytic capacitor just because I happened to have the matching values already in my project box.

The major gotchas:

You *will* end up sending some springs flying, so for disassembly:

1. Remove all the keycaps, being very careful with the plastic stabilizers on the spacebar etc
2. Take a photo of the board upright with all the springs in place
3. Find a way to prop the board upside down supported on the sides (so the springs are just hanging, not pressed against anything)
4. Open the plastic case -- try to be gentle with the plastic clips, if you snap the ones in the middle of the board it may not work after reassembly because the feet won't be held firmly against the membrane
5. Maybe take another photo of the flipper feet in their original spots

There's some more info here https://www.instructables.com/id/Clean- ... -keyboard/

[nickg]

Hmm reading that thread the ceramic seem to last longer? Maybe I'll just order those now to be ready then.

[abrahamstechnology]

Just use ceramics or poly caps of the same value. But you can go up on voltage.