Those tests are not complete in a sense that they do not guarantee that the IC will work properly.
But they clearly indicate if it is bad and while it’s not guaranteed, we find that 99.9% of the time when an IC passes them it works good on a board.
It all boils down to detecting continuity (shorts) or low resistance (ohms) between certain pairs of pins on the module..
If you find one the STK795-518 is certainly bad.
The tests can be done with the IPM on or off the board.
Here’s a picture of the pins of interest:
As you can see there are 4 points of interest – GND (Ground), Vs (supply power), SUS and ER, which are the two outputs for the sustain and energy recovery accordingly. Those two are shorted on the board, but on an actual IC are NOT connected to each other.
Here’s the simple rule:
THERE MUST BE NO CONTINUITY (SHORT) BETWEEN ANY COMBINATION OF THOSE!
IF YOU FIND A SHORT THEN YOUR STK795-518 IS DEFECTIVE.
This is actually 100% correct for all other plasma IPM modules.
There are 4 inputs/outputs which result in 6 possible tests (Vs-GND, Vs-SUSout, Vs-ERout, GND-SUSout, GND-ERout, SUSout-ERout), but in reality two are the most common failures that we see in STK795-518:
1) Vs shorted to one of the two sustain outputs:
2) The other sustain output shorted to ground:
