If your patches are still intact after you power off and you have no C cells in the synth, then the battery is good.
If you lose your patches after you power off and back on and you have no C cells in the poly, then the battery needs to be replaced.
/Mike
From: "bagaeta@... [korgpolyex]" <korgpolyex@yahoogroups.com>
To: korgpolyex@yahoogroups.com
Sent: Thursday, November 26, 2015 10:57 PM
Subject: Re: [korgpolyex] Poly800 DCO 1 does not play the right notes
To: korgpolyex@yahoogroups.com
Sent: Thursday, November 26, 2015 10:57 PM
Subject: Re: [korgpolyex] Poly800 DCO 1 does not play the right notes
Thank you. Is there any value in replacing that battery with a fresh one? It must be dead by now...
Bruno