Amp going into protect after upgrading power and RCA

[MoonMaster33]

I just upgraded my power line from an 8 to a 4 after having power issues and ran some new RCA's too. I have a 1200 w class D mono amp. After the upgrade everything worked for a few minutes then it just started going into protect mode on heavy bass, but now I'm not getting any sound and the power/protection light is flashing.

Any recommendations on how to process the troubleshooting process? I'm not sure what to do next as I can't understand how upgrading a power line could cause this issue.

Any help would be greatly appreciated.

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[Deiimos]

Unhook the speaker wire at the amp terminals, and unplug the RCA cables at the amp. Power the amp up and see if it comes on out of protect.

If it’s still in protect, you need to measure voltage at the amps 12v+, GND, and REM terminals to verify it is still getting proper power to turn on.

Lastly, what exact brand model / amp is it?

Electronics do fail, so there is a chance the amp is bad, and the cutting out (or whatever power problem you were having) prior to upgrading your wiring was an early symptom, and now it is finally dead. But can't condemn it yet.

 

[MoonMaster33]

Unhook the speaker wire at the amp terminals, and unplug the RCA cables at the amp. Power the amp up and see if it comes on out of protect.

If it’s still in protect, you need to measure voltage at the amps 12v+, GND, and REM terminals to verify it is still getting proper power to turn on.

Lastly, what exact brand model / amp is it?

Electronics do fail, so there is a chance the amp is bad, and the cutting out (or whatever power problem you were having) prior to upgrading your wiring was an early symptom, and now it is finally dead. But can't condemn it yet.

Thank you for responding. I have unplugged the speakers, RCA's, and remote punch level, only leaving the power ground and remote connected. When I do a voltage test from the ground to the power I'm getting about 9 volts and then I'm getting about 8 and 1/2 over the remote. The amp is a Rockford fosgate prime r1200-1d.

 

[Deiimos]

If it is still flashing the protect, 9 volts is a little low which "might" be the reason, check the voltage at your battery to make sure it is showing a charged battery / functioning alternator = 12.6v to 14v roughly. 8.5v is also pretty low on the remote wire, although might be enough. 9v at the amp is too low though, I just don't know if this will trigger the protection but likely would.

 

[MoonMaster33]

If it is still flashing the protect, 9 volts is a little low which "might" be the reason, check the voltage at your battery to make sure it is showing a charged battery / functioning alternator = 12.6v to 14v roughly. 8.5v is also pretty low on the remote wire, although might be enough. 9v at the amp is too low though, I just don't know if this will trigger the protection but likely would.

I have ~14.5 at the battery, in for the line fuze and exit of it. The protection light is now solid after I disconnected the speaker wire. More a a purple as both the Blue and red LEDs are on.

 

[Deiimos]

Okay that’s good, and if both sides of the fuse show that, that helps rule out the fuse / holder at the moment. If you still have about 9v at the B+ and GND amp terminals, there is possibly a bad ground / connection at the amp side.

 

[MoonMaster33]

Okay that’s good, and if both sides of the fuse show that, that helps rule out the fuse / holder at the moment. If you still have about 9v at the B+ and GND amp terminals, there is possibly a bad ground / connection at the amp side.

I'll check on that. I didn't upgrade the GND as it was already 4 awg. I'm not 100% sure how to go about that, but if I had to guess I would disconnect the B+ and GND from the amp and check the voltage between the two or would that be an impedance check on just the ground cable and the chassis?

 

[Deiimos]

Measuring impedance / resistance of the "power wire" won’t really help here most of the time unless it is completely "open" somewhere in the system. It will more often than not read okay with a meter, but once you apply current, is when it falls on it’s face. A common volt meter won't simulate a load.

A simply thing to try is ground the amp somewhere else.

It might be worth just hard wiring the amp directly to the battery to test it. If you still have the 8 gauge you swapped out, run it from the NEGATIVE battery post back to the amp ground in place of your old ground wire, then see if it turns on (this bypasses the old ground / vehicle chassis ground). You can either try to use the head unit to power it on, or unhook the REM wire from the amp, and run a short wire from the B+ terminal to the REM terminal to manually turn it on. If you can verify the amp works, then you know it has to be a bad connection somewhere.

Which brings another question.

For the ground; Did you sand the paint to bare metal? Any rust? Did you use a nut and bolt / ring terminal to clamp the ground tightly? I'm leaning towards a ground issue, but hard to say for sure.

I know this sounds like a lot, but should only take a few minutes to test, maybe 10 minutes if you hardwire the amp.

 

[MoonMaster33]

Measuring impedance / resistance of the "power wire" won’t really help here most of the time unless it is completely "open" somewhere in the system. It will more often than not read okay with a meter, but once you apply current, is when it falls on it’s face. A common volt meter won't simulate a load.

A simply thing to try is ground the amp somewhere else.

It might be worth just hard wiring the amp directly to the battery to test it. If you still have the 8 gauge you swapped out, run it from the NEGATIVE battery post back to the amp ground in place of your old ground wire, then see if it turns on (this bypasses the old ground / vehicle chassis ground). You can either try to use the head unit to power it on, or unhook the REM wire from the amp, and run a short wire from the B+ terminal to the REM terminal to manually turn it on. If you can verify the amp works, then you know it has to be a bad connection somewhere.

Which brings another question.

For the ground; Did you sand the paint to bare metal? Any rust? Did you use a nut and bolt / ring terminal to clamp the ground tightly? I'm leaning towards a ground issue, but hard to say for sure.

I know this sounds like a lot, but should only take a few minutes to test, maybe 10 minutes if you hardwire the amp.

Thank you so much for your recommendations and help. I ended up locating the ground connection and it was very corroded. I picking a different location nearby and ground down all of the paint to bare metal. The amp is now powering up and I'm getting roughly 14 volts at the terminals. I have reconnected everything and the system seems to be functioning now. I'm honestly surprised the amp was able to function with the 8 gauge wire seeing how bad that ground connection was.

 

[Deiimos]

Glad to hear it was a simple fix and the amp is working again.

The 9v reading indicated it was likely a bad connection somewhere.