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: <767@csd4.milw.wisc.edu>
Date: 3 Feb 89 20:55:52 GMT
References: <435@manta.NOSC.MIL>
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Organization: UW-Milwaukee Home for Out-of-date 8 bit Hackers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: 39

In comp.sys.cbm article <435@manta.NOSC.MIL>, mitch@manta.NOSC.MIL (Ray Mitchell) wrote:
]Has anyone encountered any problems with repeated failures with the 6526A IC
]IC in the C64? I think they call the IC an ACI. The system has two of them
]but the one interfacing to the joystick ports and keyboard is the one giving
]me the problems.
]
]I have been through about four of them in the last 2 years and I am ending
]up investing more in them than I have in the computer.  I even bought a
]different computer thinking it might be something in the system but the
]new one also blows one about every 6 months (The new C64 is using a different
]power supply than the old one).

I would suggest that static electricity may be at fault.  The CIA is
an extremely static sensitive device, and the joystick ports are
directly connected.  A good way to zap a 64 is to discharge a little
static electricity in a joyport....

]The problem usually manifests itself by the joysticks failing to respond to
]a certain direction or a key on the keyboard failing to operate properly.
]These ICs cost $17 each from Commodore and about twice that locally.

Of course....  try mail-order.

]Commodore has no one that I have been able to contact intelligent enough to
]discuss this problem but I'm sure they would deny a problem anyway. My only
]solution is to build a replacement from discrete TTL which technically is
]no problem but I don't beleive the part is explained sufficiently in the
]programmer's manual to premit this.  Commodore is obviously no help on
]this either.

Don't kid yourself....  Commodore knows that this is a problem.  And
building a complex device like a CIA from "discrete TTL" would be
overkill (not to mention that it wouldn't be physically convenient).

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