# Alpine amp issue. No sound.



## DR OBLIVION (Jun 16, 2009)

I'm still a little new to the forum even though I've been lurking for a long time. Anyways, I had an issue with an amplifier and I don't expect anyone to be able to tell me what's wrong with the amp just from my description of the issue. I was just wondering if anyone could possibly give me an idea if this amp is worth fixing(I'd rather not spend $100 to repair an amplifier thats barely worth $80). It was an awesome amplifier when it was working.

Model:Alpine V12 MRD-M500

Issue: Amp powers up, voltage monitor etc. lights up/functioning. No sound.

Background: I let someone borrow the amp. They secured it to the back of an enclosure even though I advised against it. A screw that secured the board to the chassis came loose and was tumbling around the underside of the amp where everything is soldered to the board. When I tested the amp there was some playback coming through my sub but very, very, very low. The cone was just moving enough to feel it with your hand. I disconnected the amp and installed my Rockford T400-2 and it was powering the sub nicely so it's not an install/poor signal issue.

I've taken the amp apart and pulled the board out to see if anything noticeable was wrong but I don't know very much about the electronics inside. Nothing stood out from what I could see.


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## Syaoran (Jun 27, 2011)

Maybe something shorted inside the amp?


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## sqshoestring (Jun 19, 2007)

Its up to you, I ran one for a while then swapped to the M301. Not sure it has quite enough power at 350rms going to change that out too. The 500 worked fine, the digital features are nice but sort of a pain to use without a controller. It likely shorted something out, or could be from the board moving, hard to say. I would check the RCA plug and controls first to make sure they don't have a bad solder from vibration. Hook it up and gently move the RCA plug/gain/etc (the non-digital controls/plugs), turn it off and change the switches or just push on them a little without moving them while it plays, palm the amp a little see if vibration changes operation to check for connection issue. Otherwise try to find someone that does it on the side, not sure how you do that. I mess with them but don't like to do them for people, I can't let them sit when I get busy with other things lol.

Before you do any of that test the outputs for voltage that could trash your sub, should be little to none present. You can sell broken amps on epay.


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## kvndoom (Nov 13, 2009)

You check all the settings? Did you verify the gains and all were where you left them?


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## minbari (Mar 3, 2011)

if a screw rolled its way across the bare board, it could have shorted out any number of things, including the final output devices.


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## splaudiohz (Apr 1, 2011)

minbari said:


> if a screw rolled its way across the bare board, it could have shorted out any number of things, including the final output devices.


Yeah, that is a bad day.


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## HondAudio (Oct 19, 2006)

minbari said:


> if a screw rolled its way across the bare board, it could have shorted out any number of things, including the final output devices.


</thread>


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## dragonrage (Feb 14, 2007)

How about you request that the person you lent it to replace it? I would sever all ties with any 'friend' who borrowed something, broke it and refused to compensate me for it.


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## DR OBLIVION (Jun 16, 2009)

kvndoom said:


> You check all the settings? Did you verify the gains and all were where you left them?


Yes, all the settings were the same.



minbari said:


> if a screw rolled its way across the bare board, it could have shorted out any number of things, including the final output devices.


That's what I was afriad of and I think it is the final output devices.



dragonrage said:


> How about you request that the person you lent it to replace it? I would sever all ties with any 'friend' who borrowed something, broke it and refused to compensate me for it.


It was my youngest brother. The amplifier was collecting dust in my room so it doesn't bother me but I do want it working though. My brother replaced the clutch in my car by himself  and never asked me for a cent so there's really no hard feelings here.


A little update :

Took it to a local repair shop. The tech said the preamp inputs were bad and that he can't replace them because it was too complicated of a repair for him on this particular amp.


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## sqshoestring (Jun 19, 2007)

Inputs are usually opamps. Likely is SMD its a pain if you don't have the solder equipment.


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