[Coco] Coco1 repair parts ?? & Results of Repair!!

[Robert Emery]

Inspired by your success, Robert, I kept plugging away at my CoCo1
troubleshooting... very lucky I had two identical F board CoCo's handy and one
of them worked.

The first thing I found when I removed the tin shield over the RAM chips was
that all eight chips were barely pressed into their sockets. Whoever built the
thing must have been worried about pressing down too hard. I can't believe it
worked for me for so long... at least six years and much of that in all-ram
mode.

So I thought "This must be the problem" carefully re-seating all eight chips...
nothing changed. Garbage at power up. So I start swapping in chips from the
known-good unit. Ram chips... no change. 6809... no change. 6847, 6821, 6883...
no change. It's not looking good.

So I changed tacks... rather than trying to make the broken one work, I'll put
chips into the working one until it breaks. Not only the SAM chip, but all the
ram died as well. The dead one has 8040517's and the good one has 8040665(?).
Can these be intermixed? CoCo was dead with any one of them in the board.

At any rate, by putting the good SAM & RAM into ol'grey, I got to see her
cursor flash again, so I know she's fixable.

Bob

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