I’ve got power, I’ve got patches on the screen. Buttons work, voices seem to light up as indicated. I’ve replaced internal battery, I’ve replaced internal fuse, I’ve checked the firmware, I’ve factory reset and sysex dumped patches onto the board, still no sound… any ideas or suggestions? No cables are undone and no solder points seem bad…
I fixed a matrix 6 once buy swapping out all the chips that are for the oscillators. I believe there is 6 . I ordered them from ebay I think from Portugal or something weird. Took a few weeks to get them but sounded amazing when fixed. I wish I didnt sell it so cheap. Homer simpson lives on!
Whenever I hear someone describe a situation where a keyboard LOOKS like everything is functioning, yet it makes no sound, my first thought is a bad op amp chip somewhere in the output circuitry. This will take some signal tracing to find the culprit. Probably a $.50 part that takes a lot of time to track down…
Try carefully un-seating and then re-seating the voice chips in their sockets. I did this with mine with some success. Look for corrosion on the chip feet as well and try an remove.
I think there is a video or a thread on this topic on Gearslutz