RE: CSG5710 (was: is there any easy way to upgrade a C116 to 64k)

From: Bil Herd <>
Date: Thu, 2 May 2013 15:57:01 -0400
Message-ID: <>
>Just nitpicking:

* On Thu, May 02, 2013 at 06:04:26PM +0200 Gerrit Heitsch wrote:
> MOS did some CMOS chips, the ones I know are:
> 5710   found in C128DCR, simplified CIA

>simplified CIA and substitute for the WD1770/WD1772, but with a different
programming model... *grmph*

>This resulted in the 1571 equivalent inside of the 128DCR ("1571CR")
being almost completely incompatible with the 1571, because almost all
locations in the area $8000-$BFFF are different.

>Whoever came out with this should have been fired...  or promoted, it
Commodore really wanted to make it cheaper. ;(
> Regards,

The _original_ C128D was the exact same C128 with the second reset switch
stuffed.  I left before I realized they hadn't followed through with
selling the D right away, and only recently (one year ago) heard of a
"Metal Case" or DR version.  I pulled the schematics from zimmers and a
quick glance made me think it had been done by CBM Germany (I could be
wrong, it just reminded me of their drafting style) and I noticed that
they took out my wacky last minute kludge with the transistor for the Z80
Clock, and replaced  with three Open Collector devices in parallel with a
rather low value of resistor. (Talk about throwing wattage out the window)
I laughed when I saw it as being different yet not normal, like someone
really hated the transistor kludge as much as we did, but couldn't really
do it easily for the same cost.  (I walked the kludge around to every
engineer including the ones I didn't really respect and begged for someone
to point out why it would break under use)  I also heard that the DCR or
metal case had more video noise but haven't seen one myself. (lol ...
probably Z80 clock noise and bad ground)

So if you're saying someone changed the memory map when cost reducing we
tended to castrate someone that screwed with compatibility.

So I have one maybe two of the original C128 D in plastic cases with the
original C128 board with the fan in the case.  (My ex-girlfriend's little
brother has my third one)  Did this ever ship?

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Received on 2013-05-02 20:01:00

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