Amp not working?
10-04-2008, 05:56 PM
#1
0 Watt CAFz'r
Thread Starter
Join Date: Oct 2008
Posts: 2
Amp not working?
So I have an Alpine MRP-M500 and I got it all hooked up and everything and no sound comes out of the sub!
Upon powering up the car, the light on the amp comes on, on then quickly goes off.
I pulled out a multimeter and checked all the connections, they seem to be ok. But then I check the amp and between the ground and power in terminals, there is 500,000 Ohm (0.5M ohm) resistance which seems kind of minor but could this be the source of my problem?
I don't know why but sometimes there is no connection between the power and ground terminal, and then when I start connecting things (maybe the RCA inputs), I get the issue (I think).
Could the amp have some kind of intermittent connection?
The car still runs fine and the stereo still works and all, just the amp doesn't power up (not enough power from the battery perhaps as it is a regular car battery)?
Upon powering up the car, the light on the amp comes on, on then quickly goes off.
I pulled out a multimeter and checked all the connections, they seem to be ok. But then I check the amp and between the ground and power in terminals, there is 500,000 Ohm (0.5M ohm) resistance which seems kind of minor but could this be the source of my problem?
I don't know why but sometimes there is no connection between the power and ground terminal, and then when I start connecting things (maybe the RCA inputs), I get the issue (I think).
Could the amp have some kind of intermittent connection?
The car still runs fine and the stereo still works and all, just the amp doesn't power up (not enough power from the battery perhaps as it is a regular car battery)?
10-06-2008, 06:41 AM
#2
2000 Watt CAFz'r
Join Date: Jan 2001
Posts: 2,026
Since no one has replied yet I'll give it a try.
I sounds like there is a ground issue - either in your car or in the internals of the amp. The reading that you got from the terminals of 500,000 ohms should not be a problem. That's all fo the stuff inside the amp - and since current does need to pass through in order for the amp to run, I wouldn't worry about that number at this point.
Turn your multimeter down to much lower setting - the setting that reads resistance in single digits. Test from the ground screw of the amp to a piece of bare metal on the car. If you get a number higher than 1 ohm, it would be wise to re-ground your negative wire. However, with the problem your describing, it sounds like the ground connection is so weak that the amp is able to power up but then has no place to dump the current so it shuts off. Then in the off process, the current slowly trickles out allowing to repeat the process again.
Perhaps you could take the amp out, pop your hood and connect the amp straight to your car battery. If you do this, and the problem disappears, then you know that the problem is with the internal wiring of your car. If the problem persists - then your guess about an internal problem with the amp is likely the problem.
Before you do that, one other avenue you could try is look to see if something is shorting on the output. Disconnect all speakers / subs and try turning it on again. If the problem disappears and it stays on, then start examining the speakers / subs for faults. It is a long shot as most amps have protection / fault circuits with an independant light, but it doesn't hurt. If the problem persists I don't have a clue.
I sounds like there is a ground issue - either in your car or in the internals of the amp. The reading that you got from the terminals of 500,000 ohms should not be a problem. That's all fo the stuff inside the amp - and since current does need to pass through in order for the amp to run, I wouldn't worry about that number at this point.
Turn your multimeter down to much lower setting - the setting that reads resistance in single digits. Test from the ground screw of the amp to a piece of bare metal on the car. If you get a number higher than 1 ohm, it would be wise to re-ground your negative wire. However, with the problem your describing, it sounds like the ground connection is so weak that the amp is able to power up but then has no place to dump the current so it shuts off. Then in the off process, the current slowly trickles out allowing to repeat the process again.
Perhaps you could take the amp out, pop your hood and connect the amp straight to your car battery. If you do this, and the problem disappears, then you know that the problem is with the internal wiring of your car. If the problem persists - then your guess about an internal problem with the amp is likely the problem.
Before you do that, one other avenue you could try is look to see if something is shorting on the output. Disconnect all speakers / subs and try turning it on again. If the problem disappears and it stays on, then start examining the speakers / subs for faults. It is a long shot as most amps have protection / fault circuits with an independant light, but it doesn't hurt. If the problem persists I don't have a clue.
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