Pure Sine Wave Inverter 3000W repair

I was given this inverter for free, that if I can repair I can use as a backup power.

"Pure sine wave Inverter 3000W"
"Power that really moves"
"DC-AC"
text on the top of the case.

When i first opened it I did notice a burned YMP230N55.
I found on aliexpress that they offer YMP230N55 as a replacement for the more expensive IRF2804.
I bought 5x IRF2804, replaced 3x of them, the burned one, and one next to it, and the one closest to the right end of the board. I have 2 more IRF2804 to test with.

I turned on the board with the replaced FETs and we heard a sound that the inverter powered up actually for a second.
The same mosfet that was burned, smoked out immediately.

What can be causing this ? Any ideas by looking at the pictures ?





Thank you in advance

First of all you have to repair the PCB as soon as possible. It is burned and started beeing conductive. The track at the edge of pcb seems to be broken.
Next, when replacing transistors i inverters, you should replaca ALL of them from the SAME batch and do not mix transistors (YMP and IRF).

Who is the mfr ?
Power Jack ?

One or both of the problems below ...
a) Is the Gate Input "ON" when is should be OFF, ie Gate always ON ?
b) Is the Output side / load side, on that MOSFET, shorted ? ie too many amps when that MOSFET is ON ?

summitville said:

Who is the mfr ?
Power Jack ?

One or both of the problems below ...
a) Is the Gate Input "ON" when is should be OFF, ie Gate always ON ?
b) Is the Output side / load side, on that MOSFET, shorted ? ie too many amps when that MOSFET is ON ?

Click to expand...

MFR is some Chinese company, not even written anywhere on the board neither on the case.

a) yes
b) yes

What part is causing this to happen ?

Check Q12. It is quite possible that this transistor is shorted causing the MOSFET to burn.
Moreover do validate the connections of R12 and the lower end of vertical resistor in Attachement 3 near the burned PCB portion.

Dear Sirs
I have a similar problem with my two Chinese 3000w Power Star W7 inverters but the problem seemed with the control pcbs, i couldn't get a replacement. i tried to repair but PCBs are smt and difficult to repair. i am looking for a working pure sine wave inverter circuit diagram to construct.My transformer primary is a two wire and not center taped, and all mosfets are n ch IRF3205 in an H bridge configuration please help.