Korg Poly800/EX800 Users

I recently did the battery backup mod on my Poly 800 MKI.  I used a salvaged motherboard lithium battery thingy with a new 3v CR2016.  Originally, I found that

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

By the memory IC do you mean IC22?

Alec Jahn wrote:
> By the memory IC do you mean IC22?
> 

Can't remember off the top of my head, but the 6116 CMOS static memory, 
not the EPROM.

Gordon

Ok, I m sure I ll find it (not at home at the moment :/ ) but if you ve got a pointer on where to find it (left, right, center of the board) it would probably

Alec Jahn wrote:
> Ok, I'm sure I'll find it (not at home at the moment :/ ) but if you've 
> got a pointer on where to find it (left, right, center of the board) it 
> would probably help me when I tackle it.  Is it a standard wide chip or 
> a slim skinny one? [____] vs [_________]

24-pin chip, one of the wide ones, IIRC it's a 6116 but I could be 
wrong.  It should be near the CPU and EPROM.

Gordon

It s getting 2.707v with the power off (I assume there s a capacitor on that as well, I had it on and turned it off, and dropped from 3.XX+v to 2.7v and stayed