I rec'd a cooked UPS unit, outputs were shorted and smoke was seen. Opened it up and there are four rows of 5 output power transistors. Two rows look fine, two rows are blown so badly it looks like there was actual flame up the heatsinks. Bunch of resistors in the general vicinity are toasted as well, and some of the PCB traces are melted pretty bad.
Okay, I know that this is a candidate for the dump, but other than the output transistors, everything else okay. As the unit originally cost upwards of $1000, maybe it's worth $25 worth of parts to fix it.
The melted transistors are Fairchild NDP708AE's. They are N-channel enhanced mode MOSFETs, rated at 80V and 60A continuous current.
I have two specific questions:
- Does anybody have a source for these?
- Would it be okay to go with a slightly higher (or lower) rated unit? I see that mouser carries an 80V/50A transistor made by STI Micro that has very similar specs, same power dissipation rating.
Thanks for any help
Dave