Lightening audio strike S2.1000.1D

[imraneesa]

Hi all
This amp using 65N06 as power fets with 56ohms gate resistors. Can I use 3205 with same gate resistor values. Some fets they made 56ohms in two 26ohm resistors in series.

Next is the out puts are MTP45N20, can I use IRF3415?

Then lastly what IC they used on output driver board. Is it 4080?

 

[Perry Babin]

What's the rail voltage?

The 56 ohm is borderline. If you don't want to replace the gate resistors, confirm that the FETs run cool at idle (full duty cycle). To get it to full duty cycle at idle, you may have to reduce the 12v supply voltage.

Compare your board to the attached image.

 

[imraneesa]

Got power fets and I installed them. The amp is still going into protect without outputs on board. When I removed output driver board the amp came on. So I guess the audio driver ic must be bad.

 

[Perry Babin]

Do you see DC on the output filter inductors when it goes into protect?

Is the relay closing?

 

[imraneesa]

No dc on output terminals. And relay dont close. But if I remove the driver board. Amp coming on and relay closes.

 

[Perry Babin]

Are you sure that there isn't an instantaneous pulse of DC on the inductors that could be tripping the protect mode?