I presume this is possible with power off, looking for resistance between drain and source?
I'm pretty sure I've killed it - resistance is 0.33Ohms between these two pins Out of circuit, on a good one, it is > 13MOhms. Looking at my circuit, I've solder the Schottky Rectifier the wrong way around - cathode to ground Pretty sure that won't have done the Mosfet any good, it was too hot to touch. Can't believe I've been so stupid - by good luck, rather than management, the other Schottky I have in the circuit (not shown below) is the right way around.
Is there a way of testing the Schottky rectifier in-circuit - I've tried it and the DMM 'beeps' as it detects a normal junction; measures 0.159v and 0.579V depending upon orientation of test leads? Just to clarify - in the schematic below you can see how the Schottky rectifier should be - however, as I say, it's actually reversed and I don't know if that might affect readings. So, with the COM lead to the cathode and test (red) lead to anode it reads 0.159v; with the COM lead to the anode and test (red) lead to cathode it reads 0.579V. I can test one out of circuit and I get 0.157V and OL respectively. I think that indicates it is ok but in circuit it isn't reading as OL: I have to remove it to swap it around in any case so would the advice be to chuck it and use a new one?
I'm really hoping I can get it off with wick and an iron and without damaging the board; ditto the Mosfet. I really don't want to lump out for a rework station.
Is there likely to be damage to other components down stream? Any tips for testing components without removing them from the circuit?
This is only part of the circuit but shows the relationship between the Mosfet and Schottky rectifier:
[silently screaming inside]