Vortex Sound Research

I recently picked up a used Korg minilogue from a pawn shop with 5 broken/ dead keys. I opened it up and thoroughly cleaned the entire pcb/ key contact board with a qtip and alcohol. I also made sure the rubber and carbon pads were working by pressing one of the ones from the working keys to the broken ones. No response. I've watched several videos on youtube and none of them have suggested any other fixes. I need help fixing my korg minilogue.