From: Wolfgang Moser (womo_at_news.trikaliotis.net)
Date: 2006-08-31 19:48:28
Hi Cameron, Marko,
Marko Mäkelä schrieb:
> On Wed, Aug 30, 2006 at 08:36:57PM -0700, Cameron Kaiser wrote:
>> Anyone seen a *partial* failure of CIA #2? Serial bus (including 128 mode
>
> I have experienced partial chip failure. You can fry individual pins of
> chips. I once installed a cable between the user port of a Commodore 64
same over here. I shot many poor CIAs and VIAs
(floppy) due to inappropriate use of a Commodore
parallel cable known from hardware floppy
speeders.
Sometimes only a few bits get stuck as Marko
said, sometimes some of the port bits become
unable to pull an external TTL input to high
level which "converts" them to Open Collector
drovers. On some chips a complete 8-Bit port
is blown while the other one is working fine.
Sometimes you can recognize defective building
blocks of a CIA from within an In-System view
(memory monitor), sometimes the internal
register interface works fine, but the
external "interface" does not.
Mostly I saw blown parallel ports, because
these were the parts I played with. Don't
know if there is a chip in my collection with
fully working 8-Bit ports but other building
blocks malfunctioning.
Bye, Womo
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