Archive of the former Yahoo!Groups mailing list: Korg Poly800/EX800 Users

previous by date index next by date
previous in topic topic list next in topic

Subject: Re: [korgpolyex] Batter Backup Mod Issues

From: "Alec Jahn" <ocedtotehmax@...>
Date: 2008-10-20

By the memory IC do you mean IC22?

On Mon, Oct 20, 2008 at 3:23 PM, Gordon JC Pearce MM3YEQ <gordon@...> wrote:

Alec Jahn wrote:

> Any sort of stuff I can check? Some of those trimpots that may be...
> off? I'd love to use this in a performance in the future, but won't if
> I have to bring a laptop/mp3 player just to reprogram it when I get
> there. I suppose that wouldn't be too bad...

Could be a few things. The battery may be flat, or the memory IC may be
damaged. My money is on the battery being flat...

Check the voltage across the 3V lithium battery both in and out of
circuit. If it's much less than 3V it's knackered. Check to see if
around 2.5V appears on the power pins of the memory IC with the power
turned off. If not, then something between the battery and the IC is fried.

Looking at the circuit diagram, it seems that the battery voltage is fed
through R1 to the IC. The standby current should be a few microamps, so
the drop across R1 would be tiny.

HTH,
Gordon