PC8801 Type A repair

[relo999]

I'm coming from the retro-PC hobby and recently got myself a broken PC8801FH, got the computer working like new and works great with a PS2 toPC88 converter I build, but they keyboard that came with it is still not in a working state. Roughly 1/3rd of all switches didn't work and some sometimes registered multiple keys. So I desoldered all keyswitches as most wheren't working, not realizing I could have cleaned and fixed them being soldered in. On top of that 2 switches where completely broken and missing a right spacebar. Now all switches are working (checked with multimeter) and the PCB doesn't seem to have any issues.

So my question would be how can I get the switches back in place as I feel like lining them all up in one go would be next to impossible. I imagine there is a trick for it that I dont know.
And aside from the SKCM Blue's that are in the board, are there any other switches that are similar enough and could be mounted on the same footprint? (and maybe tips on where to source a right spacebar from might help)

PS. I noticed the heavy blues from the PC88 stop and copy keys aren't listed under variants of the SKCM series.

[Muirium]

I hadn’t heard of this board or its NEC non-IBM “PC” platform. Did dig up a couple of examples of the keyboard though. I always want visuals.

Snacks has a nice one:
viewtopic.php?f=62&t=21510

And Nasanieru has a bigger version which has a split spacebar as you say:
viewtopic.php?f=2&t=25648

Blue Alps should respond well to waxboil, though less is more and cautious experimentation is highly advised.

[jsheradin]

This is an Alps board right? Some photos might help since there's about a million PC88 boards. Assuming it's Alps:

If you're just wanting to get it up and running reliably, your best bet is to pop in some Matias switches. They're brand new drop in replacements: https://matias.store/products/matias-cl ... box-of-200

If you're looking to keep it original and the current switch plates chatter, you might be in for a challenge. Unfortunately Alps switchplates don't really have a good way to clean them. Even if they test OK on a multimeter they might still act up in a keyboard. You might have luck with some contact cleaner or spamming them a zillion times but the longevity of the repair is always questionable. Best option is to swap the plates with working ones. There's quite a few places you can source old but working switchplates cheaply.

Once you have working plates you're onto making the switches themselves feel nice to use. I'm a believer in wax + wet lube. The combo has been great on every board I've tried but it's a touchy process to get right.

Assembling the board should be pretty straightforward. Just clip the switches into the metal plate, solder them in, and it'll be all lined up.

[relo999]

Thanks for the tips!

The board before disassembly: https://imgur.com/a/MJnXRSo Had taken the picture for future reference. Right now 2 boxes of switches, keys and separate plate, pcb, wire and housing. As I suspected that there was some PCB issue and with loads of bridges and no good ability to check under the plate I decided to desolder everything and clean the switches. PCB was fine, just extremely dirty.

Update:
Got all keys to work, except for the 2 very obviously broken (though the switches inside seem fine). Just a matter of full disassemply of the switchplate. The only keys I haven't been able to test are the "PC" key and what Google translate tells me is the "full width" key, no clue how to test seeing as they also dont do anything in BASIC with the keyboard converter but those I suspect are fine. And the multiple key thing seemed to be something from the plastic part taped to the back of the PCB as removing that it works fine, might also be the tiny switch on the PCB which I have no clue what it does.

So now it's just the quest to find a right spacebar keycap and get 2 switches to replace the broken ones.