Re: 2001 repair help

From: vossi <vossi_at_ceffy.de>
Date: Wed, 27 Dec 2017 12:18:34 -0700 (MST)
Message-ID: <1514402314677-0.post@n4.nabble.com>
Normally at this boards the half of the 6550 and some 6540's are dead...
Often the 6520 are faulty too.
The sockets are a very big problem. Commodore used in the old 2001 the high
black sockets with metal outside - these are very bad! Also they have not so
high sockets with metal contacts inside - these are much better. And they
used TI-sockets with very thin holes - these are the best!.

I have a rom-replacement board that fits in H2 to H5 as 6540 replacement.
And I test the RAMs and ROMs with my 2001TEST in H7 (with adapter 27xxx to
6540). You find it here: http://lc64.blogspot.de/2016/10/

Poking and peeking to $8200 worked, but on the screen is still a wrong char.
That was because the screen-display-counter D7 74177 has probs with the jump
to the highest bit.



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Received on 2017-12-27 20:00:03

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