[Coco] 6821 PIA Chip Bad?

[Steve Batson]

Sounds like something is shorted.


Steve Batson
Batson Photography
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On Apr 27, 2011, at 11:30 AM, Eric Keppel <keppel at earthsounds.com> wrote:

> Hi Coco Folk!
> 
> Well, I purchased another Coco on eBay, and unfortunately, it got lost
> by the USPS for about a month and then suddenly appeared at my door
> yesterday.  The delay was caused by the box ripping apart, and the Coco
> obviously fell out and got caught on a conveyor belt or something.  The
> case is really beat up now and the power and reset button are missing.
> 
> Anyway, I powered it up and it wouldn't boot (garbage on the screen,
> sometimes an orange screen, and once in a while the ECB 1.0 message,
> missing key presses from some keys).  Even when it would manage to boot,
> it would always lock up in about 60 seconds or so.
> 
> I cracked the unbroken warrantee seal (bummer) and opened it up to have
> a look.  It's an older gray Coco1 with a Rev. E board and 16k.  After
> checking that all of the various chips were seated well, I noticed that
> one of the 6821 PIA chips was running VERY hot.  I just about burned my
> finger on it.  Well, I swapped the two PIAs with one another and it
> booted right up nicely, but didn't stay up for very long, then that same
> PIA chip got hot again and the machine locked up.
> 
> So, I am suspecting that the hot PIA is bad since it got hot regardless
> of which socket it was in.  In fact, when I put my finger on it, the
> machine stayed up much longer, presumably because my finger is acting as
> a heat sink and keeping the chip going a little longer.  This is very
> unscientific, but my best guess.
> 
> I see that the chips aren't too expensive, so I was thinking of getting
> one to replace it unless someone has a better suggestion or sees
> something I missed.  Am I on the right track?
> 
> --Eric
> 
> 
> 
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