My Amp Tech says.

VHT Repair:
Looking at the circuit board I found a resistor that was burnt pretty much in half. The resistor in question is R159, as you can see in the pictures. I could still read the color code and seeing that it was a larger resistor I replaced it with a 5 watt ceramic to insure it was enough to take the current. This worked, initially, but the customer reported there was a slight "thump" when the Standby was turned off. Apparently this grew into a much louder noise and other issues began to show - some channels noisy, etc. Looking into it again I saw that the solder was practically blown out of one end of the replacement resistor and it had burn marks on that end. If I had a schematic I would know more how to trace the problem and remedy it.

I hope you can help my customer. I can follow any instructions you may care to offer.
Thank you,
Ken Graves
Activax Amplification

My Sig X was purchased from Musicians Friend circa 2008