Ensoniq TS-10 slow key and keys stuck on high aftertouch

My Ensoniq TS-10 have a problem with the keyboard on the first (low) octave. The other 4 octaves are fine and have normal functionality.
The first problem is a “slow” key. It’s the second c-key (white key number 8). It feels like normal when pushing it, but goes back to default position slowly, so it becomes difficult play notes fast.
The other problem is all the keys from first E to the second D are permanently stuck on high aftertouch. For instance, the sound will be very loud on them, or sometimes bring in a vibrato, depending on the preset. I’m pretty sure its aftertouch because the setting “Program Control -> Press = off” fixes the problem, but then of course, there is no aftertouch on any of the keys.
Does anyone have suggestions how to repair this?