Ensoniq ESQ-1 sustain pedal or expression?

[Pik0]

So I’m trying to get a sustain working on this old ESQ-1 keyboard. So far i’ve tried a standard TS style pedal which yielded zero results in any voice. In reading the schematic, it looks like it’s expecting a TRS style pedal. If that’s the case, how does that work and what does it do? Variable sustain?

TIA!!

Andrew

• Model & revision/OS: 2.0
• Symptoms (what changed, when): no sustain
• Tests already done (voltages, parts replaced): tested TS pedal okay
• Photos / audio clips:

[Pik0]

[Travis]

Any normally open foot switch should work. Make sure you plug it into the Sustain Ft. Sw. input and not the CV/Pedal input, that’s for an expression pedal.