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34401A ohms drift
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Kleinstein:
It depends on the position of the FET. The one for the protection is used as a diode and here low leakage is essentially the only important point. So the PN4117 is good (alternative would be a low leakage diode).

The other FET is for the current regulation and this would need a fet for a higher current. Rethinking this, this one should be a p channel FET - so not the J112.

With the diode used FET in the protection broken, suspicion is high that some of the high voltage PNPs may also be bad. To damage the protection diode would need the PNPs to brake down and this can very well cause a damage there too.
strawberry:
With PN4117A
daveyk:
Was the fault Q202, MMBF5461SEL?  I can not find MMBF5461 anywhere right now. 

All the PNPs test okay.

Not sure what Q211 does.  I think it must be used for its gate leakage.
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