Yes, version 8 has a lithium coin cell soldered in. I don’t think I’ve ever
seen a schematic with this revision. I’ve seen KLM-596-2,6,7 and 8 boards and
the only schematic I’ve seen was for version 2, with no battery and no solder
tabs where the battery would eventually be added. Versions 6 an 7 had the solder
tabs but no battery, and R1 and D1 had to be removed from the board when adding
a battery. Version 8 had no R1 or D1 on the board. This resistor and zener diode
used to be over near the 9V input.
Don B.
Sent: Thursday, November 26, 2015 8:18 PM
Subject: Re: [korgpolyex] Poly800 DCO 1 does not play the right
notes
Thank you! I'm not sure my multimeter is accurate enough to measure the voltage that precisely. But in a fit of desperation I attacked the board with a Q-tip and contact cleaner and sure enough rubbing the bottom right pins of IC18 (right under the coin battery) and R65 fixes the problem, at least temporarily. I'll see how it goes before seeking a more permanent fix (fingers crossed).
BTW the coin battery is not shown on the diagrams in the service manual. Is
this because I have a newer board revision? My main board version is
KLM-596-8
Bruno