[Coco] Yet Another Disk Pak Issue (was Re: Help reviving an old CoCo 2)

[Arthur Flexser]

I'd still try the pencil eraser method, rubbing until the pins look shiny.
If you aren't going to do this 3 times a week or something, I wouldn't
worry about abrasiveness.

If that fails, another possibility, especially since 2 different
controllers are giving you a problem, is that the problem might be
associated with the 6809 CPU.  I've seen cases where a flaky CPU can give
rise to problems only when a disk controller is in use.  If you have
another CoCo and the CPU is socketed, try swapping in the other CPU
(doesn't matter if it is from a CoCo 3 or a CoCo 1/2), and see if that
helps.

Art

On Wed, Nov 26, 2014 at 8:43 PM, John Goerzen <jgoerzen at complete.org> wrote:

> Arthur Flexser <flexser at ...> writes:
>
> [ Art replies to me saying I'm buying a FD-501 pak on eBay ]
>
> >
> > Even if it doesn't work, might be useful as a source of chips to try
> > swapping with identical ones from the other controller to see if that
> > revives the first one.  A bad WD1773, the main disk controller chip,
> seems
> > like a likely suspect.
>
> So the pak arrived today.  I can make it work - sometimes.  About 50% of
> the
> time, when the disk controller pak is inserted, the computer powers up to a
> green screen and... nothing else.  Just an empty green screen.
> Occasionally
> there are other random display artifacts.  Wiggling or bumping the
> cartridge
> seems to have an effect, so I suspect the problem is contacts on this one.
>
> I tried cleaning them with contact cleaner and a Q-tip, and although they
> weren't visibly dirty, that did get some off.  I don't want to be too
> abrasive, and I'm not convinced this will really solve the problem, but --
> ideas at this point?
>
> I don't want to keep sinking money into controller paks, but there seems to
> be nobody selling them other than "as-is".
>
> Thanks,
>
> John
>
>
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