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Subject: Re: [korgpolyex] Power on issue with Poly-800

From: billmeirelles@...
Date: 2011-07-04

1 - Have you checked your power supply unity?
2 - Have you tried with a diferent power supply?
3 - Have you tried to resolder the power supply connector in the poly 800 pcb?
4 - Have you checked the battery wiring? If the positive wire is in contact with
ground the power loss will be huge, even when the power supply is in use.
5 - Have you give the pcb an isopropyl alcohol bath using a tooth brush? It can
help you see clearly to trace any broken solder or bad parts, also it helps to avoid
ground loops created by conductive dust.
6 - Don't set VR1 to max as it can get something fried, let it in the middle position for
now and when you get the poly to powerup properlly than you adjust it as the service
manual describes.

Em 04/07/2011 16:49, 7yash < josh.nursing@... > escreveu:

Hi all, just got a second-hand, quite battered Poly-800.

As you expect, it has the lost or randomized patches issue.

It also has an issue with the power supply: it won't turn on with the external power supply. I managed to turn it on with the internal battery leads connected to a 9V battery initially.

Now, what it does is it will sometimes turn on (sometimes not) and only for a few seconds on internal battery - anything from 2 to 10 seconds. This is, of course, annoying, since it's not even enough to play back the factory patches in Tape Mode.

I have searched a lot on the forums including this one, have replaced the Q1 transistor with a new PNP. I have yet to try changing the nearby Zener diode (9/10V).

I just bought a multi-meter (it's analog) and a continuity tester, have plenty of replacement parts, also downloaded the schematics and read everything on this forum concerning battery issues.

Hav e been going through the service manual testing procedure. Currently, even with the VR1 trim-pot adjusted to the max, there doesn't seem to be enough voltage.

Any guidance would be thoroughly appreciated.

Yash