Gianmario's 64c mystery solved

From: Marko Mäkelä (
Date: 2003-07-07 22:35:17

Gianmario visited my place tonight, and I had a look at his computer.
I should have paid closer attention to his description, as I was surprised
to find the "monster PLA" chip on the board (for which there might be no
other replacements than the do-it-yourself project on FUNET).

However, you could blindly type commands, and the memory seemed to be okay:
I loaded a compressed executable to the computer via the C2N232 interface,
and it decompressed and started okay, except for the graphic data.  The
16k video bank selection was obviously at fault.

So, I desoldered pins 2 and 3 of U2, the $dd00 CIA, and the correct graphics
started to appear (not all the time, because the -VA14 and -VA15 lines were
now floating).  Afterwards, I measured that pins 2 through 4 were all 0 volts,
although they should be 5 volts.  So, the $dd00 CIA is broken, and Gianmario
will have to replace it.


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