No Amp Power
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=29190
Printed Date: July 12, 2025 at 4:33 AM
Topic: No Amp Power
Posted By: rwhite625
Subject: No Amp Power
Date Posted: March 28, 2004 at 4:05 PM
I installed an amp in a Blazer about 2 years ago and it has been fine until about 2 weeks ago. The amplifier is not powering up all of a sudden. I checked the fuse on the power wire and it is fine, I am getting 12 volts all the way to the amp. I checked the ground and it is fine too. When I check the voltage at the amp it is 12 volts until I turn the stereo on then the voltage drops to nothing. I am getting 12 volts from the remote lead from the head unit also. I checked for a fuse on the amp but there are no external fuses. I'm not sure what is going on here? Please help.
Replies:
Posted By: netboy
Date Posted: March 28, 2004 at 4:15 PM
Sounds like your amp took a dump on you. This happened to me on my crappy 5ch MTX. It worked fine for a few months then all of the sudden it stopped working. All fuses and wiring were correct. Amp just died and didnt want to work anymore. The guys at the stereo shop said some how some voltage came back up through the speaker wire and fried my amp. I say BS. But they replaced it neverheless. ------------- Memphis MC-1300
2 12" JLw6v2
Diamond audio M3 6x9
Diamond audio M3 5.25 components
Audio control Matrix
Carputer
Posted By: rwhite625
Date Posted: March 28, 2004 at 4:16 PM
I tried another amp and the same thing happened.
Posted By: DYohn
Date Posted: March 28, 2004 at 4:18 PM
You say you turn the stereo on and the voltage drops to nothing. Measured where?
Posted By: rwhite625
Date Posted: March 28, 2004 at 4:21 PM
Measured where the power wire connects to the amp.
Posted By: DYohn
Date Posted: March 28, 2004 at 4:28 PM
Hmm. The only way that can happen is if the amp (or something else - do you have another amp or a capacitor?) is shorted and killing your voltage - or if the main power fuse is actually blown and just looks OK under no load. I suspect the reason it is doing that is when you turn on the HU that is activating the remote on wiare and turning the amp on, but it is internally shorted. First of all, if you have any other item in the circuit, especially a cap, remove it. The way to check the amp would be to leave the HU off and temporarily connect a wire from the main power to the remote on terminal. Monitor the voltage and if it drops to zero as soon as you touch the remote terminal, the amp is fried. If this turns the amp on OK, then check your remote wire and see if it is cut or damaged between the HU and the amp.
Posted By: rwhite625
Date Posted: March 28, 2004 at 4:32 PM
No, there is nothing else on the circuit at all. I tried connecting the main power to the remote on terminal and the voltage still drops. I've tried it with 2 different amps and it does the same thing with both.
Posted By: rwhite625
Date Posted: March 28, 2004 at 4:34 PM
Also, I forgot to mention, I connected both amps to a 12V power supply and they both turned on.
Posted By: DYohn
Date Posted: March 28, 2004 at 4:40 PM
OK, if you have the same symptom with two amps it is unlikely they are both fried. If you've tried the wire trick, then it is not your HU. You must have an issue with the power system between your battery and your amp, or in your ground. You either have defective wires or fuses or both. Check and clean all your connections looking for corrosion or loose connections. Check the main engine ground strap and your battery ground cable and make sure they are not corroded. Replace the main power fuse even if it looks good. Check all your cables. Look for cuts or breaks in your power and ground cables. Run new cables.
Posted By: superstreet786
Date Posted: March 28, 2004 at 5:35 PM
check your remote connection and also make sure the amp isnt just goin into protection mode
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---- 1996 Chevy S10 ----
1 Lightning Audio S2.600.2 Amp
2 Lightning Audio 12" Subs
1 Lightning Audio 1 Farad Cap
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