Re: C128D

From: Nicolas Welte (
Date: 1999-03-17 10:13:49

Richard Atkinson wrote:
> > I personnaly prefer the plastic type because the other one has some
> > incompatabilities and is less easier to repair.
> Are these incompatibilities the same as the C64 / C64C ones? Both later
> machines use 9V HMOS chips, but I've not seen the same level of cost
> reduction in the C128DCR as compared with the C64C. All Commodore seem to

The only obvious component changes in the C128 part of the 128DCR are
the 8580 SID instead of the 6581 one and the 8568 VDC instead of the
8563 one. I never heard that one of these ever caused any compatibility
troubles. But there are other, less obvious differences. E.g. CBM
changed something about the CIA timers from 1987 on, so 1987 and later
6526 chips behave a little bit differently than older models. The newer
models seem to assert the IRQ line on a timer underrun one cycle earlier
for some reason, this causes the trace mode of SMON to fail, for
example. Naturally all machines manufactured after 1987 (C64C, C128DCR)
and all machines that have been repaired with new chips suffer from this
problem. But actually there's only one other program I know of that had
problems with this behaviour, it's the 15 seconds parallel copier. Funet
has a fixed version. Maybe the biggest problem are the new ROMs of the
128DCR, both the C128 ROMs and the 1571 drive ROMs are new revisions.
Since the 128DCR was the first 128 I had, I don't know if any of the
programs that failed on this machine wouldn't have failed on an original
128D, and I'm not gonna try that now ;-)

This message was sent through the cbm-hackers mailing list.
To unsubscribe: echo unsubscribe | mail

Archive generated by hypermail 2.1.1.