Thanks for the pointer to that schematic of the power supply. After
comparing it to the module it turns out that the Q7 on that schematic
is the transistor I was referring to. I re-examined the module under a
microscope and the label on the board is Q2 so I'm not sure how the
mixup in the labelling between Q2 and Q7 happened. All the other
components on that schematic appear to be labelled the same as on the
circuit board. Oh well, at least it confirms the part number as being
what I thought it was. Thanks again for your input.

Cheers,
Lawrence