polysix troubles

[Christian Hofmann]

On Mon, 16 Oct 2000 22:56:53 +0000
djblue <djblue at graffiti.net> wrote:

> old crow?  anybody that knows about the polysix?
> 
> I'm trying to diagnose why half of the buttons don't work on the
> memory section.  I thought it was one of the IC's in there (there
> are 4) but I swapped them all around one at a time and the problem
> never changed, so now I think it must be something else, but don't
> know where to go from here.  any suggestions?  


Ah, it's this month's sick Polysix...

Are you sure it's NOT the infamous leaking battery?
When I had it finally happen on my Polysix, it _was_ acting strange
concerning the panel buttons. One of the 74LS08s (IC30 & 31) near the
battery was partly dead, causing data bus problems. 

IC 30, pins 2/3 and 12/11 would be the usual suspect for memory button
trouble.
If you have a scope you could see if there's some continuous digital
noise at pins 3 and 11. If one of those pins is dead - there you have it.

regards
Christian