Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ukma!rutgers!cbmvax!fred
From: fred@cbmvax.UUCP (Fred Bowen)
Newsgroups: comp.sys.cbm
Subject: Re: C64 IC Failure
Message-ID: <5943@cbmvax.UUCP>
Date: 9 Feb 89 22:03:21 GMT
References: <435@manta.NOSC.MIL> <3715@uoregon.uoregon.edu> <689@wpi.WPI.EDU>
Reply-To: fred@cbmvax.UUCP (Fred Bowen)
Organization: Commodore Technology, West Chester, PA
Lines: 35

In article <689@wpi.WPI.EDU> dchen@wpi.wpi.edu (Daniel D.E. Chen) writes:
>It's strange but I recently took a new C64c apart and found much to my
>dismay the whole circuit board is changed.  The MPU, 6581 SID, and 3
>ROM were replaced with a large 40 pin MPU, a 6582 SID and 2 ROMS.

The MPU (8500 MPU) is the same as always- it's just a 6510 in new clothes.
The SID (6582 aka 8580) is the same except pin 28 (vdd) is now at 9V.
The BASIC and kernel ROMs have been merged into one, the character ROM is
unchanged.  The biggest change is the gonzo 64-pin gate array, which combines
much of the TTL glue with the old PLA, and the used of 64Kx4 DRAMs.

>I also saw something really interesting about the design, there were
>little capacitor in series with each line of the joystick, probably
>there to prevent "electricution" of the CIA chips.

No, they are EMI filters designed to prevent FCC trouble, not protect the CIA.

>Would anyone know what the new MPU is and what is differnt about it?
>It seems capatible with the 28 pin 6510.  Does anyone know I can get
>the new schematic for it?

See the description above; sounds like you are confusing the processor with
the gate array (aggravated by some serious pin miscounting :-)

Service centers are allowed to sell schematics and service manuals if they
want.  Many are reluctant to do so, fearing competition and/or loss of
business I would guess.  Still, that the board has changed in what, 6 years,
is no reason to be dismayed.
--
-- 
Fred Bowen			uucp:	{uunet|rutgers|pyramid}!cbmvax!fred
				arpa:	cbmvax!fred@uunet.uu.net
				tele:	215 431-9100

Commodore Electronics, Ltd.,  1200 Wilson Drive,  West Chester,  PA,  19380