Is my car stereo head unit fried?

Why does the head-unit in my car stereo setup keep turning off?

• I've installed a stereo setup into my car recently (Nissan Pulsar SSS, SR20DE), which consists of: Alpine CDE-102E Head Unit Alpine MRP-F200 4 Channel Amplifier Alpine MRP-M500 Monoblock Amplifier Kenwood KFC-W3010 Subwoofer Alpine SPR-17C Co-Axial Speakers (4 of them) I'm running 4 gauge wire from the battery to a splitter that makes 4 connections of 8 gauge wire. Both amplifiers are powered by separate 8 gauge wires and are well-ventilated in a custom install. The head-unit has been installed using wire harness connectors. One harness connector houses all the factory speaker wires (which has been disconnected now due to using the RCA Cables; left/right "Front" connections for the 4 Coaxial Speakers, left/right "Rear" connections for the Subwoofer). The other harness connector houses the power, ground, ignition, mute, remote, and illumination wires. The connections have been double-checked with a multi-meter to test for resistance across a wire/connection and have all come up with very low resistance. Everything worked fine before the amplifiers were installed, but now the head-unit turns off and then on again randomly. I thought this might have been a battery/alternator issue, but I tested them with the multimeter and got 12.75 volts when the car was off (left for 12 hours), and 14.14 volts when the car was running, which is fine. The amplifiers are earthed at the same bolt in the boot of the car, I don't know if this is an issue. Possible Causes: - Shorting out somewhere - An earthing point isn't sufficient enough to be an earthing point - Battery/Alternator needs replacing - Gain on the amplifiers hasn't been set properly (I don't know much about gain on amplifiers) - Something is causing to head unit to turn off as a safety precaution - Power is being cut to the head unit - Ignition is being cut to the head unit Notes: I've noticed that my saved Radio preferences have not been lost, suggesting that power is not being cut. The headlights do not dim, and no other electronics in the car have ever hesitated when the music was playing, suggesting that it is not a low battery issue. The head-units battery and ignition connection runs from the factory wiring, but the amplifiers power and wires are aftermarket installs that run through a fuse in engine bay, if the problem was isolated to the amplifiers it wouldn't cause the head-unit to turn off. Any speakers could be out of phase, as I have not thoroughly checked them. Are there any tests I can do to work out where the problem is coming from? (I have a multi-meter) Any solutions to the problem? Any help on the matter is greatly appreciated.

• Answer:

  did you connect the rear channel rca outs (both left and right) to your mono amp? if so does your mono amp sum the input rcas? when it comes to sub amps you should only supply a mono signal unless it says it can take both left and right channels and then sum them to a mono signal. try taking either L or R channel out of the mono amp (leaving just one connected.) If it was a short with power wires you would blow a fuse and not be able to turn back on, or you would melt a wire and possibly cause a fire and still not be able to turn back on. If it was a short with the speaker wire coming out of the headunit then theres a good chance that will send the headunit in protection mode and shut off. Check to make sure the rca out isnt touching metal either, likely not the problem but nice to rule it out. When grounding amps try to ground to the metal frame and sand down any paint. If its a ground problem you could get lots of interference and poor voltage at the amp. check the dc voltage at your distribution block for power and ground near your amps. battery and alternator wouldnt cause the head unit to turn off and not the amps as well. Gain would not cause the headunit to turn off either. Improper gain setting can cause clipping in the amplifier and cause that to go in protection, not the headunit. check ignition source voltage of the headunit and amps. note if it drops when it turns off.