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Loud "thud" when powering up amp!?

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Old 04-06-2011, 07:50 PM
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50 Watt CAFz'r
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Loud "thud" when powering up amp!?

Well recently I noticed an major issue with my setup. When I start the car and the head unit fires up with no issue. The remote for the amp lights up for about 6 seconds then I hear a loud thud from my subs... then the remote light turns off... basically the amp is shuting itself down. I have no bass and only my door speakers work. Nothing has been changed or moved around the past 2 years.

What I have done so far...
- checked remote wire (repluged it in)
- checked all wires connected to head unit (all are soldered and heat shrink wraped) and appear fine
- checked in-line fuse near battery (150amp anl)
- checked amp fuses (40's)
- checked all wires from amp inc. ground, 12v wire, sub cables
- checked battery terminals and cables

Any idea's what may be the problem? I'm thinking the amp may have an issue??

note: specs in sig....
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Old 04-06-2011, 09:36 PM
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Originally Posted by shawn76
The remote for the amp lights up for about 6 seconds then I hear a loud thud from my subs... then the remote light turns off... basically the amp is shuting itself down.
Use a DMM and monitor the voltage for the remote wire. When the amp turns off, is the remote still at 12v? If you dont have a DMM you could use a small piece of wire and jump the 12v to the remote (I would unplug the remote wire from the deck if you're doing this.) and see if it still does what you said.

You need to narrow it down to either the deck or the amp. You could get a 3.5mm jack (headphones) to RCA and use your mp3 player as the audio source.

Try this and report back with the results.
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Old 04-06-2011, 10:15 PM
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good ideas...will get back to you. Thank you!

Last edited by shawn76; 04-06-2011 at 10:26 PM.
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Old 04-07-2011, 12:55 AM
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Remove speaker wires between sub and amp to take subs out of the picture. If one was dead shorted internally it could turn the amp on to protect mode. Just a quick troubleshoot.
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Old 04-07-2011, 04:29 PM
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Thanks Mr. DatSUBishi but I already checked that. I did however notice something when removing the amp cover a few minutes ago. 3 of the 4 large 80V capacitors are bulging at the top. Not good. Sending it back to manufacturer.

Thanks for everyones input...
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