Re: Static PET repair (was Re: VCF PET Alive! - April 24th to May 2nd)

From: Marko Mäkelä <>
Date: Tue, 30 Mar 2010 09:15:21 +0300
Message-ID: <20100330061521.GA24025@x60s>
On Tue, Mar 30, 2010 at 02:00:03AM -0400, Ethan Dicks wrote:
> > If I remember correctly, the very first defect of my C64 was that it hung
> > when trying to write to tape.  Apparently, the 6510 on-chip I/O port had
> > been damaged so that when it tried to wiggle the CASS WRITE line, also the
> > memory configuration lines were being changed.
> Ouch.  That must have been a fun one to diagnose - the machine "runs",
> so the CPU "must" be good...

Yes, and the screen would blank as it should.  Only the SAVE command would
never complete. :-)

The funny thing was that it was probably caused by hot-plugging a tape drive
in order to copy games without having to adjust the head alignment. :-)
You know, it was the "punishment" for the "sin" of copying (which was not
illegal here at that time, for private use).

If anyone wants a car analogy, there have been rumors that cheap
<insert foreign nation name here> fuel could damage the engine.
(As far as I understand, many Finnish people living close to the Russian
border are circumventing the domestic taxes by filling the tank abroad.)
This was the case of such a rumor coming true. :-)


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Received on 2010-03-30 07:00:20

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