Behind the Yamaha PS-30's "Solo" section, there's a simple monophonic analogue synth. Here's how I brought the filter and tuning controls to the front panel...Quite simple, it's involves removing 3 trimmer pots from the PCB and replacing them with regular potentiometers mounted on the front panel. First, however, much gratitude goes to the excellent Table Hooters site for the detailed information on this keyboard's inner workings: http://weltenschule.de/TableHooters/Yamaha_PS-30_PS-20.html (click images to enlarge) My Yamaha PS-30 - the green, blue and red knobs (top right) control de-tune, cut-off frequency and resonance respectively You can already access the solo section's tuning control via a removable plug on the back of the case: Removing this plug allows access to a trimmer pot on the PCB. I replaced this with a regular pot mounted on the front panel. Back of case removed... The solo section PCB is the shaded area on t