Ensoniq SQ-2 in unknown condition

I’ve got an SQ-2 that is missing 2 keys, and also two faders/sliders. It powers on, gives a low battery notice, then moves onto the main menu. I understand that the synth would not make any sound of the battery was dead, so I will start with that. Does anyone have any experience repairing these, or any advice they could give to a guy who has only ever fixed guitar amps and such?