Author Topic: [Help] IBM Model F PC 83 issues  (Read 2661 times)

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Offline Unxmaal

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[Help] IBM Model F PC 83 issues
« on: Sat, 05 August 2017, 16:26:21 »
Hi all!

I just got my IBM Model F PC 83 functional for the first (for me) time. I connected a Teensy 2.0 and used Soarer's latest firmware.

Unfortunately, I'm having problems with a few keys. The keys' flippers appear to sometimes 'stick' in a down position, meaning they'll actuate the keyyyyyyyyyyyyys until I manually unstick them.

What's the process to fix this? Should I do a full teardown, foam replacement, sandblast, respring, and so forth? Where's the best guide for that?

Thanks!

Offline fohat.digs

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Re: [Help] IBM Model F PC 83 issues
« Reply #1 on: Sat, 05 August 2017, 16:54:54 »
First, I would pull the key and re-seat it. Maybe jiggle things like the spring around a little bit.

Look for something that might be dirty or sticky somewhere.
“No political truth is of greater intrinsic value, or is stamped with the authority of more enlightened patrons of liberty: The accumulation of all powers, legislative, executive, and judiciary, in the same hands .… may justly be pronounced the very definition of tyranny.” —James Madison, Federalist 47
“All the powers of government, legislative, executive, and judiciary, result to the legislative body. The concentrating of these in the same hands, is precisely the definition of despotic government. An ELECTIVE DESPOTISM was not the government we fought for; but one .... in which the powers of government should be so divided and balanced among several bodies of magistracy, as that no one could transcend their legal limits, without being effectually checked and restrained by the others.” — Thomas Jefferson, commentary on Federalist 48

Offline Unxmaal

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Re: [Help] IBM Model F PC 83 issues
« Reply #2 on: Sun, 06 August 2017, 10:49:02 »
Looks like the foam mat disintegrated and got sticky dust all over the PCB. I've torn it down and will replace the foam.

Offline Unxmaal

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Re: [Help] IBM Model F PC 83 issues
« Reply #3 on: Thu, 10 August 2017, 19:49:20 »
I've done a complete and total teardown and rebuild of this board.

https://imgur.com/a/M7TBV

Unfortunately I'm still having a few flippers that "sometimes" don't seem to actuate.

Currently, they're all working, except for F10, but this seems to change if the board gets moved around.

Any thoughts or advice on this?

Offline Unxmaal

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Re: [Help] IBM Model F PC 83 issues
« Reply #4 on: Wed, 16 August 2017, 14:07:47 »
Since I'm the only person posting here, I'll answer my own question:

This happened because the springs for buckling spring keys are really, really picky about being in the correct "spot", inside the cap.

For each key that was "stuck", I reseated the cap, sometimes several times. Eventually the spring settled in the right place, and the key tested properly.