I'm not really good with a multimeter, but....
Just tested the Diode. I'm measuring 587 and 1. No beep though.
Also noticed when measuring that the wires from the diode are black, I could scrape black dust off of it. (see picture)
http://dl.dropbox.com/u/7760238/poly%20800/Diode.JPG --- In korgpolyex@yahoogroups.com, Gordon JC Pearce <gordon@...> wrote:
>
> On 28/07/12 18:33, Martin Ator wrote:
> >
> >
> >
> > If there is no pop and nothing on the display, or any other noises, then
> > probably power isn't getting into the circuits. Any of the parts
> > designed to protect against short circuit in the power circuit could be
> > dead. The diode I told you about is a good candidate to start looking
> > from. I have had to replace one in the past. If you have a diode test
> > you can check this or just see if 9v is getting to the other side of the
> > diode.
> > I think it is the same as a 1N4004 diode.
>
> http://www.oldcrows.net/~patchell/poly800/poly800.html
>
> Check the 2SB744 "pre-regulator" regulator, which is in the negative
> lead from the power socket.
>
> D2 is just to protect against incorrect polarity.
>
> --
> Gordonjcp MM0YEQ
>