Commodore B128 with I/O issue

From: B.Degnan <>
Date: Thu Sep 18 14:55:05 2003

I have a Commodore 600 series B128 (low profile version similar to the
European 610) and I have been trying to diagnose a problem and fix. I do
not have diagnositcs for one of these guys to check the chips
automatically. When I power on the machine, it reports to be READY with
BASIC version 4. I can type one line of code (for example: 10
PRINT"TEST"), but when I hit enter, the cursor disappears and no more
screen IO can be generated. In other words, the cursor does not jump down
to the next line so that I may proceed with another line of code, it just
disappears. If I reset the computer and type "LOAD" at the prompt and then
hit enter, I am not asked to start the tape drive. There is also a return
key associated with the numeric keypad but this does not generate different
results than the Enter key.

I am guessing that I need to replace a chip or two someplace. I would like
to know if any of you have an opinion/suggestions. I have found one
interesting web page,
that links to schematics, etc. I am curious if anyone has had a similar
experience with any Commodore of this era. I am sure the cause of the
problem is not unique to the 600 series. Once I have a better idea what
the problem is, I can start replacing the appropriate chips. If I can find
any (!)


Wilmington, Delaware
Received on Thu Sep 18 2003 - 14:55:05 BST

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