Why Can’t My Amp Turn On?
First make sure that the amp has a good secured to bare-metal, rust-free and also tight ground, then check the remote wire, make sure that it’s attached to the blue wire with a white stripe in it that come from the head unit and not the solid blue wire. If the problem remains, check for bad parts in the PSU (power supply unit) maybe the mosfets busted, or you can check your amp in another car just to test it. Finally you can open your amp and check for any fried components.
When Amp Goes into Protect
this may be caused by an impedance that is too low from the way the speakers are wired or a bad charging system, it may occur if the amp goes into protect while the volume is turned up. Or the output transistors failed. The solution, make sure the amp has no power, with a multimeter set to ohms, measure the resistance among the output transistors terminals, normal terminals will not show close to zero ohms, you need to remove and check the output transistors terminals if you find one or more that show 0 ohms between terminals, in some case if there are several in parallel it may indicates the whole group shorted, but usually only one shorted and the others are fine. Replace all of the transistors in that group when you find one defective transistor in a group of parallel transistors. If every output is OK, check for damage terminals on the emitter resistors.
Overheated Transistors
Set the gains/input not too high, set the impedance to level the amp rating to avoid permanent damage. Don’t put the gain to max, put it under the max. check for troubles in the speakers and its wiring to an impedance the amplifier can control. Or get a hard-wired-to-the-car external cooling such as 3-5” PC fans with an On/Off button that are perfect for car electrical system, it can also be used as a solution for amp’s volume turn down, new amp’s usually have a protected circuitry that will restrain the volume to avoid heat.
Blown Fuses
In many cases it is caused by shorted output devices or power supply rectifiers. Almost all cases of blown fuses are caused by short circuit, this may occur in the filter cap, power rails, output, and across the primary. But also check for loose particles like missing screws or nuts.
Irregular or Missing Sound Volume
There are two ways to fix this, first test it with a portable CD player to the RCA inputs and see if there is any sound, if there’s no sound, then the RCA cable from your head unit might be not good, or the head unit’s RCA output could be broken or in off position. The other way is to try it with a working speakers, if it works then the one you have is probably broken, check it with pressing down the speaker cone, if it scratches it’s definitely broken. Or maybe there is a problem with the amp itself in one of the output devices.
Bad Alternator Whine Noise from Speakers
Check the ground, if it’s OK then you’ll need a noise suppressor.
