KIM-1 restoration advice sought

From: Ross Archer <archer_at_topnow.com>
Date: Wed Jan 17 21:25:48 2001

I have a partially-functional KIM-1 (date code 0378) I'd like to
restore.
(And if anyone has one in good condition to sell, I'm also interested.)

Currently, there are two things wrong, and I'm looking for general
advice on what if anything can be done to fix them:

1. The keypad is pretty flakey. Several keys register erratically,
and when they do, they bounce and report multiple times.
The '0' key is particularly bad in this respect.
The 'PC' key is utterly caved in. But all but the PC key
registers in with varying degrees of retries and effort.

I'm handy with soldering, and could remove the keypad, but
don't have any idea how to clean / fix a keypad, let alone repair
any broken springs, contacts, etc. Can it even be done? Has
anyone here even seen the inside of one of these?

2. The cassette interface doesn't read. It writes fine, the +12 supply
is
showing up where it's expected (pin 8 of LM311) and +11-ish on the
565 PLL, but I have no idea what the "normal" voltages on each pin
are to assist in further troubleshooting. All I'm sure about is that
the
output of the LM311 is not anything like what's expected, and the
trimpot doesn't affect the PLL frequency one iota according to my scope.

Any thoughts on how to tell what section is bad?

Thanks for any ideas out there.

In the meantime, I am thinking of wiring an outboard keypad and hooking
it
to the application connector. Hand-wired, of course. Where else would
you find a 3x7 matrix?

.
Received on Wed Jan 17 2001 - 21:25:48 GMT