Massive

[Hexhclass]

This amp has no output.When I power it up the first time I saw oscillation on the high side but nothing on the low side.Now am not seeing no oscillation on the outputs.Rail and low voltages look ok.I didn’t spot any bad part yet.

Any suggestions?

 

[Perry Babin]

I expected to see at least one 6N137 optocoupler and two 5v regulators. Are they there but not in the photos?

Are you driving a signal into the amplifier? Some need a signal to have oscillation.

 

[Hexhclass]

There is one 8pin and a 4pin optocoupler

I have a signal applied

 

[Perry Babin]

Those photos show the parts I expected to see.

Are you seeing signal reaching the driver board?

What is the DCV on the mute terminal of the driver board?

 

[Hexhclass]

I get audio on some pins of the driver board.
I don’t know which is the mute pin.
Pin one being the first on the left with components facing you.

Pin1: -1.543
Pin2: 0.000
Pin3: 0.000
Pin4: -12.03
Pin5: 12.25
Pin6: 4.94
Pin7: 0.000
Pin8: 4.66
Pin9: 0.220

 

[Perry Babin]

Some pins? You should only have audio on pin 1.

Pin 3 is the mute pin. 0v is OK (mute defeat).

 

[Hexhclass]

I used a small amp to to test for audio and i heard audio on 3 of the pins.

 

[Perry Babin]

Do you have a scope?

The 'audio' could have been demodulated square waves.

Does the amp have DCV across the speaker terminals? A load across the terminals is required for some amplifiers.

 

[stocktrader200]

When a class d amp.dies the outputs and the drivers are all dead on the bad channel.

 

[Hexhclass]

With a load 0.437

I have analog and digital scope

 

[Perry Babin]

These are typically easier to troubleshoot without rail voltage. Can you remove the rectifiers?

 

[Hexhclass]

Found a shorted zd2,replace it I have oscillation but the audio output is low.I have to turn the head unit all the way up to get some bass.

I have the board out I can pull the rectifiers if needed.

 

[Perry Babin]

If you found the fault that was causing the drive problem, no need to pull the rectifiers.

Gain at max?

xo setting at highest frequency?

Bass boost at max?

Subsonic at lowest frequency?

ACV reaching RCA jacks?

ACV reaching input of driver board?