Hi Mike,
I can't see any damage to the coil. And as Marcus states in the email below; it's probably
Q1 and Q3 that's the source of the problem.
But as you say, it could be a good idea to check the capacitors aswell..
Thanks!
//Jon
--- In korgpolyex@yahoogroups.com, "patrioticduo" <patrioticduo@...> wrote:
>
> Unless you can see real physical damage to the coil, I doubt that the
> coil would be the problem. Coils are generally very reliable unless
> they are physically damaged by a direct impact, a sharp instrument
> damages the windings or corrosion from battery or water.
>
> I'm not certain of the voltages but I would check the capacitors first
> - especially electrolytic's. Of all of the electronic components, they
> age the fastest.
>
> Mike.
>
> --- In korgpolyex@yahoogroups.com, "Jon" <shonokij@> wrote:
> >
> > Hi!
> >
> > I just got myself another broken Poly-800. (The first one I got is
> now beyond repair. As I was
> > offered a second one. I thought: Two minus makes a plus..). But now,
> after picking the new
> > one appart. It seems like the -5V circuit is broken. I've replaced
> Q18. But the only reading i
> > get is +0.9V where it should be -5V.
> >
> > Could it be that small transformer that's busted? (KD-4? xD-4? It's
> hard to read the name on
> > the schematics. And it says T1 on the circuitboard). The output of
> it is +0.45V (Measured at
> > leg 1 of D10), I asume it shoudl be -2.50V instead?
> >
> > Any ideas on how to replace it?
> >
> > The long way, I guess, is to replace the entire circuit with a AC-DC
> converter that takes 9VAC
> > in and with a 7805 and a 7905 regulates it.. But it seems like to
> much trouble right now.. Or?
> >
> > Thanks!
> >
> > //Jon
> >
>