Interfire Class D amp

[Tom7227]

Maybe someone can lend a hand here,

This baby came in with blown irfz44's in the power supply. Replaced them, got the power supply working.

I power up the amp and discovered that the irf9640 begin to over heat within a few mins of turning on. Mind you I have oscillation.

You'll notice this has 2 amplifiers, both are doing the same thing.[image][/image]

 

[timwebb]

do it produce audio or pull alot of current?

 

[Perry Babin]

What is the amplitude of the gate drive signal for the 9640s? It should be about 10v and should go down to within about 1v of the source voltage. It's easier to see if the drive signal is good if you use the scope in differential mode.

Were the FETs clamped or not?