Re: C128 repair advice...

From: Nicolas Welte (
Date: 2002-02-26 10:38:33 wrote:
> The 6525A. Even I don't have any spares :( The C-port is not used AFAIK. But
> after reading the docs I noticed one bit of port C can be used as
> interruptline. I'll check that this evening if possible.
> If not all funtions/ports are used, I wonder if it would be possible to use
> a 6526, 6522 or, in the worst case, plain TTL-registers/latches.

I know someone who says he still has a few 6525s. But if you find that the
C-port is not used, or at least not used in the special 6525 mode
(handshaking and five priority interrupts), then I can send you two Rockwell
65C23 that I desoldered from an old Apple printer :-) The 65C23 is pin and
register compatible with the 6525, but it does't have the handshake and
priority interrupt mode. The very good thing is that this means that the
65C23 was second sourced by Rockwell and somewhere should be big old stocks
of those chips! 

I think that the 6525 in the 1551 drive and the keyboard-6525 in a CBM-II can
safely be replaced with a 6523 (the schematics say so). This way my 65C23s
can be "upgraded" to a full 6525 :-)


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