May contain traces of nut
I still don't see the point (and I have U52 off now anyway). I have established the voltages at the nodes relevant to the control pin are correct compared with a known working unit, so the currents must also be correct. There is nothing to be gained by subjecting U52 to abnormal drive currents, other than the possibility of characterising the defect.But it might be possible to desolder and lift just the control pin and improvise the necessary drive circuit (a small 1k resistor soldered to the control pin and connected to Fin for disable or VCC for enable?).
The next hurdle is finding out whether U53 really is redundant!