Subj : CIA Chip hack
To   : Dave Drum
From : Allen Prunty
Date : Mon Jun 06 2016 03:48:50


On Jun 05, 2016 07:09pm, Dave Drum wrote to Mark Lewis:

Dave,

I don't know if this will fix it but I have access to a couple of broken C64s
that may fit the bill.

Allen

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This text file describes what to do in order to fix Amiga 500(if one
of the CIA's is dead) with the parts taken from broken Commodore 64.

I SHALL STATE THAT THIS IS A HACK, ITS A HACK! ITS A HACK!!! HOWEVER
CONFIRMED, IT WORKS FOR ME.

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OPERATION:

So lets start. If your Amiga 500 has one of the two CIA's dead then you
can fix it for OS use and some rare NDOS games/demos. There are two such
chips(8520A), one labelled ODD CIA (A) at U7 and the second one EVEN CIA
(B) at U8, they are both socketed. The simpliest method to check which
one is dead, if Miggy does not start at all, is to remove the B one and
power it on. If it does start and shows up the so famous floppy screen,
then its obvious B died. But if it does not display anything then you put
B in place of A and try again, and if it does start then you leave it
there and go to strip the replacement chip from broken Commodore 64.

Note, if swapping chips does not work then you can stop doing anything
further as this may not

.