Amplifier blowing the Power & Output transistors.

[Gill.T]

Hello!
I have a small Genesis SM60 amplifier, I somehow short the ground wire to the power cable terminal. The amplifier fuse went out and it didn't turn on.

I found out that power and output transistors went out along with the 47 ohm resistors.
Installed new IRFZ44Ns(4) and TIP147/142(2 each), amplifier is running hot and still blowing the TIP147/142 after half an hour of running.

What am I missing?

Thanks.

 

[Perry Babin]

Post a photo of the component side of the main board.

 

[Gill.T]

I have attached few pictures. I think, I installed wrong resistor. It has to be 47ohms.

 

[Perry Babin]

The gate resistor is more likely 47 ohms than 47k ohms.

This would not affect the output transistors. I don't see anything that looks like new heatsink compound. Did you remove the old compound from all of the heatsink mounted components (including the insulators) and applied new compound before reassembly?

 

[Gill.T]

You are correct, I was testing the transistors for a short while. I had a thought, I shall apply fresh thermal paste, once I everything is ready for screw down.

 

[Osvaldo de Banfield]

Check or repace the previous stages as when a semiconductor fails, usualy kick back to the dricer stage(s).

 

[Gill.T]

Update- Got it fixed, changed the power and output transistors, along with 3 capacitors.
Its good now.

 

[Osvaldo de Banfield]

It is strange. What kind of caps?