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CP/M on the Commodore 64 [message #293376] Wed, 11 February 1987 12:08 Go to next message
Originally posted by: U267105%HNYKUN11.BITNET@wiscvm.wisc.EDU
Article-I.D.: brl-adm.4379
Posted: Wed Feb 11 12:08:19 1987
Date-Received: Thu, 12-Feb-87 07:24:01 EST
Sender: news@brl-adm.ARPA
Lines: 11

Date: 11 February 1987, 14:59:00 MET
From: Jos Grote Punt            080-566793           U267105  at HNYKUN11
Recently I received a CP/M cartridge for the Commodore 64. I know everyone
would advise me to use a C-128 to do CP/M, but at the moment I have no money to
buy one. I got this strange problem: on some machines the cartridge works, on
others it doesn't. And every time the 64 hangs at an other moment, sometimes
after 1 asterisk (there's an asterisk for every sector that gets loaded during
a cold boot), sometimes after 3 or 4 (there should be 28 !!).
Does anyone know about differences between individual C-64's ??
Re: CP/M on the Commodore 64 [message #293377 is a reply to message #293376] Wed, 11 February 1987 17:05 Go to previous messageGo to next message
Originally posted by: mwilson@pnet01.CTS.COM
Article-I.D.: brl-adm.4390
Posted: Wed Feb 11 17:05:39 1987
Date-Received: Thu, 12-Feb-87 20:07:47 EST
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     There was a problem with early versions of the 64 and the CP/M cartridge.
It had to do with timing differences between the video chip and the Z80 in the
cartridge.  Newer 64's have newer VIC chips, and the problem doesn't show up.

     Your CP/M system may also be glitched.  Does the drive light blink when
Re: CP/M on the Commodore 64 [message #293378 is a reply to message #293376] Wed, 11 February 1987 22:24 Go to previous message
jdb is currently offline  jdb
Messages: 61
Registered: May 2013
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Article-I.D.: brl-adm.4400
Posted: Wed Feb 11 22:24:57 1987
Date-Received: Thu, 12-Feb-87 22:58:25 EST
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The current issue of RUN (March 87) has a response to a letter to Commodore
Clinic on a different subject (problems with the ram expanders on early C128s)
which hints at a similar problem with the C64 CP/M cartridge.  The letter and
response are on page 92

The guy with the ram expander is treatening to sue or turn them in to the
Federal Trade Commission for false advertising.  The answer says that Commodore
had some trouble with the Feds over the C64 CP/M problem and promised they
would stop advertising products and
features not actually available.
Maybe you have some legal recourse if one of the C64s that won't run the CP/M
is yours.

You might even get Commodore to replace yours (but its doubtful) if you
threaten to bring this up with the FTC again.

David Brown
re: CP/M on the Commodore 64 [message #293379 is a reply to message #293376] Wed, 11 February 1987 21:29 Go to previous message
prindle is currently offline  prindle
Messages: 43
Registered: May 2013
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Article-I.D.: brl-adm.4397
Posted: Wed Feb 11 21:29:42 1987
Date-Received: Thu, 12-Feb-87 23:16:16 EST
Sender: news@brl-adm.ARPA
Lines: 17

The reason that the CP/M cartridge works on some 64s and not on others is that
newer 64s have an improved VIC II chip which produces proper NTSC video (the
old one had a bug and divided a clock by 64 instead of 65, or something like
that, which produced garbled color video).  The newer chip produces a slightly
different (1 or 2 percent) processor clock timing and the CP/M cartridge fails
to operate correctly.  The only cure is to use an older VIC II chip - if you
are using a Commodore 1701/1702/1802/1902 monitor with the separated video
input, the old chip looks as good as the new one.  Only the composite video is
screwed up.  Thus, if you have a friend with a C64 with the old VIC II chip but
no CP/M cartridge, do both of you a favor and trade chips with him - he gets a
better composite display if that matters, and you get a working CP/M cartridge.
The VIC II chip is the large chip to the left side under the metal "can" - it
has a blob of heat-sink compound on the top that a spring presses on when the
cover is replacd.
Frank Prindle
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