Korg Poly800/EX800 Users

Hi mike :)

I put the project aside for a while. I again made sure, that I had
the right voltages in the circuit but since I´m not a so much
experienced technician, I could not get any closer to a solution.
Maybe I have to consider a malfunction of the cpu at last. I don´t
know... a service-manual might be helpful ;/

moe

--- In korgpolyex@yahoogroups.com, "korgpolyex800"
<korgpolyex800@...> wrote:

>
> Hi Moe,
>
> How did you go working on your Poly with the weird display problem?
> Reason I ask is that I pulled out of storage my most beat up Poly

800

> and discovered that it has a very similar problem.
>
> In my case, when I power up the Poly the display immediately

shows "7-

> P". So it looks like the 7 button is stuck down. Also, if I set the
> sequencer enable switch on the back then power up the keyboard it

also

> displays "11 50 01".
>
> So I think I have a problem that is very similar to yours. I know

that

> the 7 switch is not stuck because I swapped out the main board into

my

> EX-800 and it still does the same thing.
>
> So over the next week I will be looking closely at that main board.
>
> Does anyone else have any history with the display behaving weird

in a

> similar way?
>
> Mike.
>
> --- In korgpolyex@yahoogroups.com, "m.sislack" <m.sislack@> wrote:
> >
> > --- In korgpolyex@yahoogroups.com, "korgpolyex800"

<korgpolyex800@>

> > wrote:
> > >
> > > 1.8 in the left display is not sequencer edit mode, that's for

sure.

> > >
> > > If you turn the keyboard you should get 11 P. Then, if you

switched to

> > > sequencer edit mode the display would change to 11 50 01.
> > >
> > > So it seems you have a more serious problem than just stuck

switches.

> > >
> > > Does the keyboard make sounds when you hit keys? If yes, do all

of the

> > > keys work, or just some of them? Which ones?
> > >
> > > Mike.
> > >
> > Hello Mike!
> >
> > In deed it seems to be a more serious problem. Ehen switches on,

in the

> > display is shown "1.8 50 01", but theres no reaction to key-hits

or

> > pressed buttons, not even to the switches on the back. Only when

VR1 is

> > turned, the machine awakes and starts to make weird noises like
> > uncontrolled key-hits and noise with cut off-modulations. This is

why I

> > wonder if the problem might be caused by any dead transistors Q1,

Q2 or

> > maybe Q18.
> >
> > moe
> >
>