Archive of the former Yahoo!Groups mailing list: Discussion about the Korg PolySix synthesizer

i've got a polysix with very very minor battery damage. after bypassing some traces, it's sounding great, but it's still got some major problems that I've been trying to fix with no luck for quite some time. i've built/troubleshooted a few kits successfully, I'm starting to understand how to read schematics and some of the component functions better, but I still am not very experienced and could really use some help, any specific tips would be great..

1 - primary problem is that the VCO knobs don't have any effect (it seems stuck with a default 8' saw wave). using the schematics i've tested for continuity from the solder points at CN06 on KLM369 thru most of their routes on KLM367, but everything seems to check out..i've soldered and resoldered around IC28 and IC29 and IC31..perhaps one of those IC's is shot and needs to be replaced? or does anybody have any tips or suggestions for troublespots on KLM367 that could be choking off this whole section of the front panel?

2 - i know this is a common problem, but every time it's turned on, it starts on Bank C, preset 3, and some of the programmer buttons don't work. I've been thru the adjustment/calibration procedure a couple times, but no luck..unfortunately i don't have an oscilloscope..

these were really the only problems, until recently when i was poking around IC27/IC28/IC29 and managed to short something..had to replace the fuses, and i took a shot and replaced a few transistors in the area i was poking but no luck..
3 - after the short, when the polysix is turned on, it seems to be stuck in hold mode (though no led's are lit on the key assigner section); a chord using all 6 voices (all voice led's lit) is played by a ghost. switching the key assigner to poly/unison mode makes it playable/normal again. but the arpeggiator no long works, and it worked before i shorted whatever i shorted.

i've got a handful of 4042's and a couple 74ls08's (and some ic holders) ready to order, but i wish i had a better idea of what's actually wrong before i clip off and replace more things i dont need to..

any tips for better testing/troubleshooting would be hugely appreciated! it sounds so good even at 50% working....

jt