[sdiy] Poly 61 near death?

[harrybissell]

Any Ni-Cad battery must have a trickle-charge circuit, usually no more
than a diode and resistor. Cut the diode out and you are fine.

Or you can remove the NiCad and 'or' the lithium battery in with a shottky
diode (In5819).  I do this with a 3.6V lithium.  The diode assures that you
will
NOT trickle charge.

At the time of manufacture, NiCads were the best stuff in town. Too bad they
cause so much trouble later.

I have found that some of the corrosion products are intermetallics that
CANNOT
be melted with a soldering iron. Scraping is the best way to remove. I might
add
that you can cut the affected traces, and jumper from outside the damaged
area...

H^) harry

Bob Weigel wrote:

> Hey Joseph,
>
> We are in sync here. I just got a couple of them cheap off an auction.
> The first one had a battery leak that actually took out a trace.  You
> have to scrub everything clean with alcohol or maybe there's a better
> solvent for the battery acid..I dunno. ANyone?  However I got it with
> swabs and alcohol to where it was pretty clean.  Then I 'scale' the
> surface of the traces that have begun to rust with my xacto knife with
> the curved end.  Works pretty nice.  I found one of that fat traces
> under the battery to be the only one eaten through.  I repaired it and
> the digital stuff seems to respond fine but no sound.  Tried programming
> a sound..no dice.  ANyone know if this is like the Multi-trak?  Do you
> have to load sounds first? Anyway I just verified that the patch links
> are ok and found some more to add to my site while I was at it.
> http://cu.imt.net/~sounddoctorin if you need to find patch links.
>
> I need to get a battery in it.  I can't recall if these have trickle
> charge circuits and need nicads of if you can use Li batteries.  I'll
> check before I do it.  Should be same as polysix in that part of the
> circuit and I have it's diagrams here.  If you need any parts I'll be
> scrapping one really bad unit. -Bob
>
> Joseph Palermo wrote:
>
> > I just got a poly 61 of a friend who had It sittin in his basement.
> > Most of the keys are not working properly, they don't trigger on the
> > first hit, takes a couple, some not at all. And after being on for
> > about 5 minutes it restarts it self. I took a look under the hood and
> > noticed a large battery on the cpu board, it has a small amount of
> > leakage, bout the size of a nickle, I'm guessin I need to get it out
> > of there asap. What should I do, I know of the poly 6 battery probs,
> > is the poly 61 heading for the same fate.
> >
> > Thanks in advance
> > E.O.J the Bum
> >
> >