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Amplifier Troubleshooting

Please try these things before sending in your amplifier. By the numbers, 40% of all amps returned to us work just fine and there is a problem in the wiring or install.
You must have a DMM (Digital Muti Meter) and know how to use it.
If no: take it to someone who does.
If yes: thumb through the following scenarios

Amp will not come on (no lights):

Set DMM to DC voltage and check at the amp. You need to test with both (+ & -) leads on the amplifier Power terminals.

If over 12 volts: check both sides of the fuses in the amp.
If no or low voltage: ground the DMM (-) test lead to a good, clean, metal chassis ground in the vehicle and retest.

If over 12 volts now: problem is in the ground wire or connection (between the amplifier and its chassis ground).

If still no voltage: check both sides of the fuse by the battery.

NOTE: You cannot check a fuse by just looking. Fuses can be “bad” and not blown; especially the larger, cheap-ass, glass ones.

If blown or bad: replace and start beatin’ again!

If all is good with battery voltage, it is now time to check the remote (or turn on) wire. Check voltage at terminal of amp.

If no voltage: check voltage at head unit. You can also make a jumper from the main 12V+ connection to the remote terminal to see if the amp comes on. If it does, the problem is in the head unit remote output or remote wire between the head unit and the amplifier.

If all power wiring tests good, remove the amp from the vehicle and test with short jumper wires directly at the battery, using a jumper wire from amp 12V+ to the remote terminal, just as a “I need to make sure” final test. If it still doesn’t come on, it needs to be sent in.

Amp turns on but goes into protect:

Disconnect RCAs and speakers and try turning the amp on again.

If it still goes into protect with just power, ground and remote; the amp is bad.

If it is now on and not in protect: connect the RCA’s first.
If it goes into protect: the problem is in the cables or headunit. Change and retest.

If still not in protect: reconnect speakers
If it goes into protect: problem is in the speakers or wiring (most likely shorted [or grounded] wiring or burnt coils). Set DMM to ohms and first test by shorting leads together. This number (usually in the .4 range) will be subtracted from any reading you get. Connect DMM leads to each speaker wire pair. If you have a short, reading same as touching the leads together, trace the wiring to find short.

If no short in wiring: test the speakers individually and eliminate problem.

If amp comes on (and not in protect) and has no output:

Check all settings. Turn deck on at low volume.
       Master/Slave switch in master position.
       Gain all the way up.
       Subsonic filter all the way down.
       Boost all the way down.
       X-over all the way up.

If still no sound: you will need to try an alternate input. The best is a signal generator right to the input of the amp. Alternately, you could use another radio wired in with temporary wiring right at the amp with a very short, known-working RCA cord.

If still no sound: try a known-working test speaker with very short wiring right to the amp terminals. If still no sound: amp is bad. This is a very rare failure but it can happen.

Amp has distorted output:

Same test as above. You need to eliminate all the variables.

If you are testing a stereo amp and you have the problem on one channel:

Swap RCA’s: if it changes sides, the problem is in the deck or RCA cables.

If same side: swap speaker outputs at the amp. If it changes sides, the problem is in the amp. If it stays on the same side, the problem is in the wiring or speaker.

Amp plays but has low output:

Check all settings. Turn deck on at low volume.
       Master/Slave switch in master position.
       Gain all the way up.
       Subsonic filter all the way down.
       Boost all the way down.
       X-over all the way up.

Turn up the radio. If problem remains:

Check voltage drop at amp power input terminals. Set your meter to DC voltage with the hold feature activated. If your meter does not have that feature you will need to watch it to see how low the voltage drops when it is trying to play loud. If voltage drops below 11 volts at any time, you need more battery/alternator power and or better wiring.

If voltage remains above 12 the entire time, you need to check the speakers.

Set meter to ohms and check the DC resistance of the speaker load. If it falls within the proper load for the amp, check the amp, hooked to known-working speakers. If new speakers work, the problem is in the speaker system. If it still has low output, you need to check the inputs as described above with a known-working deck and RCAs.

Amp plays but cuts off and on:

Attach volt meter to power and ground terminals at the amplifier.

Set the meter to peak hold (max/min) and display "minimum DC voltage".

Run the system until the amp shuts off and check the voltage. If voltage has dropped below 10 volts at any time, check all wiring.

Leave the meter positive on the battery wire and use a good, clean ground point on the vehicle and test again. If voltage has a higher reading than before, the problem is in the ground connection.

If it has the same voltage, work your way back to the battery; testing at any and all connection points. I.e. distribution blocks, capacitor, fuses, etc.

If at any point voltage goes up, you have found the voltage drop point.