ESQ1 volume issue

My ESQ1 sound is working, but as I play it, some of the keys will sound extremely load and stand out above the others. It’s like someone has turned the volume up to maximum and it happens when I play more than one key such as in a combination (chord). Very annoying and it ruins the song that I’m playing. It’s really weird because it doesn’t happen immediately when I turn it on and start playing. Usually happens after I’ve been playing for a while. I suspect that it has something to do with heat in the system. The volume slider doesn’t seem to be at fault. Any suggestions?

have you tried calibrating the keybed as service manual describes? also perhaps a hard reset is due. Def look the service manual over and if you’re handy with a multimeter measure the voltages and compare to what the service manual calls for. To try and narrow it down, hook a MIDI keyboard to it and see if the problem still persists.
good luck

I tried the hard reset and all of the voices went back to the factory installed ones. That’s not a problem, because I have the writeable cartridge that I save all of my favorite voices too. I’m not sure whether calibrating the keybed would do any good. The keys that play too load are random. It’s not always the same key. It could be a C and the next time it could be an E. It usually happens when I play a chord with at least three keys in unison and it’s usually the last key in the chord, like “c” “e” “G”. The G would sound like I turned the volume up to maximum. I