Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!jgreco
From: jgreco@csd4.milw.wisc.edu (Joe Greco)
Newsgroups: comp.sys.cbm
Subject: Re: C64 IC Failure
Message-ID: <854@csd4.milw.wisc.edu>
Date: 10 Feb 89 06:11:47 GMT
References: <435@manta.NOSC.MIL> <3715@uoregon.uoregon.edu> <689@wpi.WPI.EDU> <827@csd4.milw.wisc.edu>
Sender: news@csd4.milw.wisc.edu
Reply-To: jgreco@csd4.milw.wisc.edu (Joe Greco)
Organization: UW-Milwaukee Home for Out-of-date 8 bit Hackers
Lines: 53

At some time, Daniel Chen wrote to me:
] In comp.sys.cbm article <827@csd4.milw.wisc.edu>, jgreco@csd4.milw.wisc.edu ( Joe Greco) write:
] >   I have NEVER seen a 28 pin 6510....
] 
] >   What is a "large 40 pin MPU"?  The processor has always had 40 pins.
] >   What is "large" supposed to mean?
] 
] I mean to correct myself. a 80 pin MPU in the new 64c.  forty pin on
] each side of the chip.

I still doubt that.  I've never heard of an 80-pin chip.  I've seen 64
(?), I believe my old 1700 had one.  But I don't think our friends at
Commodore would mess around with the processor.  Logically, the PLA
would be the place to expand.  Most of my newer 64's have relatively
little TTL support circuitry, and I would hazard a guess that
Commodore has released a new superPLA.  One earlier model 64c I ran
into had 64Kx4 DRAM chips, and I would suspect later releases also do.

As I already suggested, IF there are only two ROM chips, I'd guess
that one is the character "generator" ROM and the other is a 16K
combined BASIC/Kernal.  If so, damn Commodore since I don't want to
muck around burning 16K EPROMs.

I am keeping in mind that Commodore has been known to do wierd things.
So I am not saying that you're not right, just that you might want to
doublecheck.

] Well on the part of the 6581 and 6582 sid chips,  I got a second 6581
] sid chip and was ready to make a piggy-back board to put the second
] 6581 chip into place to make it play 6 voices.  i.e.  Stereo
] Sidplayer.  I was surprise to find that I had to buy a 6582 at $2 
] more. 
] 
] Has anyone put together a 6 voice C64?

For a while, one authorized service shop was sending people to ME to
do such a modification "for cash".... intereresting, since I've never
done the actual modifications and don't really have great facilities.
Oh well....

The stereo chip can be a nice addition, if well programmed.  That's
the trick.... it's useless without software.

The difference between the 6581 and 6582 is, as I said, something
about electrical characteristics.  I believe the 6582 operates at 9v
instead of 12v.... or something....

sleep.  I need sleep.
--
jgreco@csd4.milw.wisc.edu		Joe Greco at FidoNet 1:154/200
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