Threshold SA/1 former S/1000 Series II

Dear all,

I've just acquired a pair of Threshold S/1000 Series II monoblock amplifiers. They seem to have been modified to the SA/1 version. One of the audioboards has been removed udedand the other board has been substituded by a gold colored board reading: #540305A
The railvoltage is now 62,3 volts what is sufficient for approx. 37 Volts at the outputs meaning 180 watts at 8 Ohm.
Can anybody with a SA/1 (optical bias or not) tell me what the biasvoltage is (110mV it should be when warmed up) and what serial his audioboard (the single small one with the biaspot on it of course) has. The serial at my board is facing one of the four large Mallory's caps located at the bottom of it.

Thanks in advance