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Subject: RE: [korgpolyex] Re: battery on Poly-800

From: "backshall1 \(dsl\)" <backshall1@...>
Date: 2011-03-13

The capacitors can't hurt anything, although they are a bit redundant. C88 is actually useful to hold the patches during a quick battery change. You said C23, but I assume you meant D23. D23 is good, since it allows the memory to use the regular 5v supply instead of the lithium cell when the synth is turned on. Do not remove it. D15 is required to protect the battery from being charged from the regular 5V supply.
 
On the other hand, there are a couple of parts that do need to be removed: R1, D1.
R1 must be removed to prevent the voltage from the AC adapter from getting to the lithium cell.
D1 must be removed to prevent the voltage from the C-cells from getting to the lithium cell. A CR2032 lithium battery is not rechargable and could overheat and burn if R1, D1 are not removed.
 
Don B

From: korgpolyex@yahoogroups.com [mailto:korgpolyex@yahoogroups.com] On Behalf Of microbugix
Sent: Sunday, March 13, 2011 4:22 PM
To: korgpolyex@yahoogroups.com
Subject: [korgpolyex] Re: battery on Poly-800

 

I now have opened my 800 too and spotted a version with solder pads, but no battery. Richard (www.analog.no) says, one should remove C87, C88 and C23. After examining the schematics at this point, I cannot imagine why this components should be removed, since the two condensors help avoiding spikes and losing memory when changing the battery and the diode protects the battery from being charged if the poly 800 is powered from the batteries in the compartment of the bottom. Or am I completely wrong there?

--- In korgpolyex@yahoogroups.com, "backshall1 \(dsl\)" <backshall1@...> wrote:

>
> Depending on
the version, this Poly-800 may not have an internal battery at
> all. It
would be on the CPU board between IC18 and IC19 if it has one. If it
> is
really old, this will be just empty space. If it is a bit newer, it may
>
have solder tabs where the battery would eventually go, but no battery. The
> last ones manufactured just before the Poly-800 II actually had a
CR2032
> lithium cell soldered in there. I this is one of the earlier two
types, it
> would need some small modifications to the power circuit to
safely install a
> CR2032
>
> Don
B.
>