could be voltage or it could also be that ur wires arnt in there good.
What was that?
10+ year member
Senior VIP Member
Check the signal at the RCA output on back of head unit and then check it at the amp. They should be close to the same (with a DMM). Also check the RCA output at the other amps. They should all be close to equal. If you're not already you use the the pre-outs from one of the working amps to feed it and that will at least eliminate an RCA output problem.
- Thread Starter
- #5
Thank you, Slaking. I don't have a dmm. How much do they cost? I would like to add that I am using the pass thru on the Fosgate for the front channel of my Alpine and there isn't any problem there. Perfect sound coming through. I'm considering picking up a different amp at this point.
What was that?
10+ year member
Senior VIP Member
You can grab a dmm at any famous auto/home store for less than $30. So your saying that your broken amp is passing on a good signal? Doesn't sound promising. Try using the fosgate to power different speakers in your car. Don't change anything but the speaker wires. If it powers them then you know your amp is fine. The p150 is a mono right? the r150 is two channel I think. If it is the two channel version you can try it bridged. Get that dmm and check out those RCA outputs. Numbers don't lie. Sometimes misleading, but never lies! How did you bench test it?
- Thread Starter
- #7
Ok check this out. I tested the head unit with a power supply on my workbench. I ran a 20' rca to the Fosgate inside the car and it worked perfectly! So frustrating uggh. I'm thinking there must be a problem with the power in my car. The hot is directly to the battery, so it has to be the red acc, which is coming from the car harness.
I am trying to decipher what you tested, but seem to be missing detail.
When you bench-tested the head unit did you have it *only* connected to the Fosgate amp?
When the head unit is in the car and does not work, is it connected to all three amps?
If so, how are you divvying up the head unit outputs to the other two amps?
When you bench-tested the head unit did you have it *only* connected to the Fosgate amp?
When the head unit is in the car and does not work, is it connected to all three amps?
If so, how are you divvying up the head unit outputs to the other two amps?
- Thread Starter
- #10
I took the unit out to try to isolate the problem. The head unit has 3 rca pre outs, front, rear and sub. I have tried all 3 amps one by one with the unit in the car and with it out. All 3 amps work fine with the unit out, (one by one and all together) but only the pioneer and Alpine work with the unit in the car. The worst part for me is that I had this whole system running off the stock stereo (not the Shaker) for the last 1 1/2 years with no issues. I had to save up for the faceplate (300.00) and head unit (another 300.00) and I've had all these problems.
- Thread Starter
- #11
Ok, Slaking......I got the dmm and I'm getting 2v reading out of the hu as well as at the end of the rca cable. I also tested the acc and I'm getting 12.02v out of that. The hot is registering 12.28v. I'm about to lose my mind here!!! Should I try to ground:*******://content.invisioncic.com/y282845/emoticons/*******.gif.a649d21efc0d1fd4890a6428166586c1.gif the hu at the battery?
CrossoverOre
10+ year member
CarAudio.com Elite
did you try taking the rear signal rca off the alpine and plug it into the fosgate? where do you have your filter setting on the deck and the amp?
brian84corvette
10+ year member
CarAudio.com Elite
use your dmm to test the amp in question in the car hooked up with the engine idling. touch the power and ground inputs to the amp with your dmm setting on dc voltage. record results. hopefully you will see 14.4 volts with the engine idling. then pop the hood and touch + and - with the dmm test leads. record that voltage. hopefully the two match.
there is a posibility that there is not a good power wire feeding your amp - and or a fuze is blown along the way somewhere.
you say it bench tests fine out of the car. then the problem is in the wring check power and ground first - then check the remote turn on wire.
there is a posibility that there is not a good power wire feeding your amp - and or a fuze is blown along the way somewhere.
you say it bench tests fine out of the car. then the problem is in the wring check power and ground first - then check the remote turn on wire.
- Thread Starter
- #14
I've tried that, CrossoverOre. I have the hu set at 125hZ and the Fosgate set at full. Even on hpf, the same result.
I'll try the test with the car running next, brian84corvette. But it will have to be tomorrow....I work the night shift. The hot lead to the Fosgate is at 12.23, as well as both other amps. The only thing I haven't tried is running the ground wire straight to the battery. I've tried the harness and the chassis behind the hu (bare metal). So it could possibly be the remote coming from the hu?
I'll try the test with the car running next, brian84corvette. But it will have to be tomorrow....I work the night shift. The hot lead to the Fosgate is at 12.23, as well as both other amps. The only thing I haven't tried is running the ground wire straight to the battery. I've tried the harness and the chassis behind the hu (bare metal). So it could possibly be the remote coming from the hu?
You could be overloading the remote turn-on connection from the HU with the three amps. Did you try temporarily jumping +12 over to the remote input on the fosgate to force it on? You could also try disconnecting the remote line from the other two amps and only connecting it to the fosgate to see if it lights up.
Activity
No one is currently typing a reply...
Similar threads
- Started by Mpbanshee
- Amplifiers 2
About this thread
