- Oct 8, 2016
As for the FETs, I would have replaced all of them
5:22 The red parts are high voltage capacitors. The one on the far left looks like it "could" be damaged. Make sure there is no damage to the casing
Not all the FETs will be activated at the exact same time, or turn off at the exact same time. They pulse on a different times to help give a sine like wave. Then smoothing capacitors and the inductors (the donut looking thing with thick heavy wire wound around it) take the somewhat jittery wave and make it a nice clean sine wave.Would you have replaced all of the small ones too? I guess I just need to learn more about how these inverters work. Based on comments from others, the small side is the high frequency switching side that feeds through the transformer. I don't understand what the function of the IGBTs is then. Unless they're taking the high frequency and turning it in to 50/60hz? But I don't see how that would be a pure sine then.
It's just blown transistor dust. I cleaned it off with the isopropyl alcohol and it looks fine visually. If I measure the pins while they're all soldered, there is no short there. It seems the short is on the DC input side of the board, so my guess at this point is that one or more of the small transistors is blown unfortunately.
Did you try lighting it from different angles? It should have a marking of some sort. Odd that they're marked Dx, for diode.