This is not a new topic but has been bouncing round for a while...seems that some M-6s develop a problem in one (or more?) voice being louder/brighter than the others on the same patch.

It may be as simple as swapping the position of 2 voice chips. Look for the board with six CEM3396s on it. They will be IDd as U101,201,...,601 according to which voice they make. You can tell which voice is flaky by watching the dots on the diaplay. Try swapping that one with another voice's chip. Thanks to Andreas Johansson on this one...mn