Amp turns on then immediately into protect and it keeps doing it

[Mell]

The title says it all. I have an planet audio AC3000.1D and it just recently started doing this. Before this happened i had two amps hooked up and i had the one with the problem as the master. When i removed the other amp from my setup the problem arose. The amp comes on fine then makes a loud "thump" noise and goes into protect. All help will be highly appreciated

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[jteske88 10+ year member]

Is it still in slave mode?

 

[Mell]

No, its in master, i also have tried turning all of the settings down but still no luck

 

[LOUDNDEEP 10+ year member]

have you tried to unhook the speakers and rca's? also have you checked your ground?

 

[Mell]

ive did that too, still no progress

 

[Jepalan]

ive did that too, still no progress

So you're saying the amp still goes into protect mode with NO RCAs connected to the AMP input connectors? And your saying the amp still goes into protect mode with NO speakers connected to the AMP output terminals? If so, the amp might be bad. If not, explain where I misunderstood you.

Did you check for solid +12 on the remote turn-on wire?

 

[keep_hope_alive Premium Member]

usually, it's blown MOSFET's that cause this. the MOSFET's are connected directly to the supply rails and when they fail they short to ground. the result is a surge of current upon power-up which the amp recognizes and goes into protect.

 

[Jepalan]

usually, it's blown MOSFET's that cause this. the MOSFET's are connected directly to the supply rails and when they fail they short to ground. the result is a surge of current upon power-up which the amp recognizes and goes into protect.

Yep - I call that a "shorted voice coil simulator". Good news is that the protection circuit still works //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[Mell]

i looked at the back of the circuit board and it looked like some type of corrosion or something. its was also spots that looked black. I also check mosfets, they looked fine

 

[6inarow]

That's flux. Get me a part number for each MOSFET on each side or a good picture ill tell you how to take them out and test them with a digital multimeter.