Rayma: did you see my post #7 above? is the Q1 in question fine? from gate to either S or D is open....
fresh ones in the pack read 5.66M from G-S or G-D. Should I unsolder the output MOSFETs and test those?
The gate should be open in either polarity to the D or S. A MOS gate is an electrode that
has no ohmic connection internally, and works by electric field like a capacitor.
The most common fault with the gate is a short to the drain or source due to excessive
voltage from static charge due to handling or a fault in the circuit. Another common fault
is a short from D to S due to excessive current.
For testing any N type fet, the red DVM lead goes to D and the black lead to S, and should be open.
For testing any P type fet, the red DVM lead goes to S and the black lead to D, and should be open.