The rectifier #1 uses several 6X5 tubes which are notorious for developing heater to cathode shorts. This grounds the B+ lead and burns out a winding. The power transformer & chokes are all encapsulated in one unit. If one winding goes open then it becomes a small boatanchor.
I always use a variac to bring the power up to 110V and no more. This ensures I don't exceed the input voltage but also allows the filaments to completely warm up. A line voltage of 120+ volts is a 10% increase in output voltage. The 540V B+ to the xmtr is now close to 600V and may stress the rectifiers resulting in a failure.
My unit has been in use for about 10 years with no problem and it's much quieter that using a CPP2 to power the dynamotor. (also much lighter
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