I ordered some IRF9Z34N MOSFETs and put them into my Taxi. I turned the machine on, with only a few lamps connected to the board. I heard a pop, and immedately turned them off. I found that the two MOSFETs connected to lamps had blown, as well as their pre-driver transistors. So, I ordered some replacement ones.
Those replacements arrived, and before putting them in, I compared them to the non-fried ones I had in there from my first order. What I found was weird.
With the red lead on the middle pin, and the black lead on the right pin on the top ones, I get .55 volts. I get nothing when the same is done on the bottom ones. When I reverse the leads, though, I get .55 volts. It seems to me that if these are both IRFZ34N's, then one pair of them is acting funny. Is it?