These early Polys stored patches with power from the C cells remove them and the presets disappear. I bought a fresh set of Cs and loaded in some patches I found online with my iPhone. I turned the machine off and left it for a few hours, and when I came back, they were still there. However, the Poly wouldn’t power on with just the C batteries. I checked the voltage with a multimeter and it was pulling 9 volts but it just wouldn’t power up.
I thought about replacing the corroded battery terminal and even looked around Akihabara (Tokyo’s electronics neighborhood) for one but no such luck. In the end I decided to leave it, since a far more convenient method for saving patches would be to put in the coin cell battery it was supposed to have.
#Korg poly 800 battery mod mod#
The mod involved clipping out a resistor and diode near the power supply and soldering wires onto the legs that are still protruding from the board.
I used a coin battery holder so it could be replaced easily down the line, and some double-sided tape and Velcro to hold it down. A flatter holder would probably be better but this was what I had, and there seemed to be enough clearance there at the back of the synth for it. I closed the synth up, left it off for a few hours, powered it back on, and my presets were still intact.