Orion

[Hexhclass]

When a speaker is connected amp will go in and out of protect continuously .signal on the outputs look good.I see 633mv offset on output terminals.

Any suggestions?

What normally goes bad on these driver boards?

So far only thing I find was a bad 5v regulator which supply Voltage to the driver board.

 

[Perry Babin]

Remove the rectifiers. Does it go into protect?

 

[Hexhclass]

With rectifiers out it does not go in protect.

 

[Perry Babin]

Do you have a drive signal on the gates of all of the output FETs?

If you don't have any drive, you may need to drive a signal into the amp.

 

[Hexhclass]

Yes all gates have drive signal

 

[Perry Babin]

Are the drive signals clean and driving back to the FET source?

You may need to load the speaker terminals for the high side.

What is their amplitude?

What is the duty cycle?

 

[Hexhclass]

I track the problem down to a bad op-amp in the preamp circuit.