Toroidal hum/buzz. Modifyed Venus PS-400A

[nobrain]

I'm modifying Venus toroidal transformer to product +/-60VDC. It produces lousy hum/buzz noise when I connected the output power transistor (load) to it. I don't hear the noise when turn it on without load.

Here is the main problem:
The primadary of toroidal consists of 6 wires(AC input), I believed it used for multiple AC input/frequency selection (example 115V/50Hz). I don't know which one are for 120VAC/60HZ. I'm more guessing and playing with it.

1) How do we find out which input wire are for 120VAC/60Hz? I appreciate if one can give me advised and idea.
2) Did anyone know the information of BTS-Venus power supply Model# PS-400A? I searched but I didn't find any useful information.
3) The label on toroidal shown Talema, 57-014852-003, 1569-XP7S4A-M, 0893, Class B1 Insulation.
4) Many toroidal transformers had 2 coils which was used for 120V/240V. What if I just use only one coil (for 120VAC) and leave another open (float)?

Thanks