Daewoo Veloce EX-7W power supply problem

[MACKE]

I bought this piano quite a number of years ago and its given sterling service uo until recently. It is currently dead. I've checked and there is power to the internal transformer, but no output from the transformer PCB to the main board. There is a plug that comes from this board to the main PCB with 3 wires, 2 red and 1 black. Does anyone have, or know, where I can get a schematic of this piano. I need to know the voltage output so that I can replace the power supply. I'm assuming that the output would be -v 0v +v.
Any help would be appreciated.