Same voltage everywhere

This is a 2000W amplifier. One fuse on the 12V line is really unlikely. The supplies rails are likely upwards of +/- 75V and running bridged to get the output power.

I haven't repaired a lot of class D amps but usually what I've seen is blown output devices causing the protection to activate, keeping the amplifier from turning on. These are really tough to figure out without a schematic. You would likely have better luck posting your questions in the car audio section of the forum. Perry Babin knows the car amplifiers very well.
 
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No, the remote trigger is what you need to turn the amp on. Have you applied power to this along with main power input?

A computer power supply will probably cycle with the start-up surge. I do not see you being able to do anything positive until you can get a battery or high current 12 VDC (up to 14.4 VDC)power supply. So until you can at least power this amp up reliably, set it aside. You will not get anywhere with a computer power supply.

@Perry Babin, can you have a look?
 
Unless otherwise instructed, place the black meter probe on the ground terminal of the amplifier for all DC voltage measurements.

Do not let your probe slip and short between terminals of the IC. If the probes are dull and likely to slip, sharpen them.

There is a 16 pin IC near the speaker terminals, post the DC voltage on all terminals using the attached pin numbering scheme. Copy and past the list into your reply.


Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 9:
Pin 10:
Pin 11:
Pin 12:
Pin 13:
Pin 14:
Pin 15:
Pin 16:
 

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Great Perry,
That's the PWM power supply controller IC. An oscilloscope would be extremely handy right after this. Look up the data sheet for a TL494 or uPc494c chip for a better understanding.

Absolutely right! Reference common ground for everything. Clip the negative lead so you have a free hand. They do make insulated covers for some meter and oscilloscope probes so you don't easily short IC pins. As Perry mentioned, slipping with a meter probe can blow stuff up. Dull probes are a sure way to slip and short, no matter how steady you think your hands are.
 
I still can't believe there is not some kind of fuse in the +12V feed line between a HIGH CURRENT source such as a large car battery and this 2 kW amplifier +12V main supply terminal.
I expect a >200A one, go figure.

If not a regular plug-in glass/ceramic/plastic type one, at least a tightly specified jumper wire or a "narrow" (for 200A that is) piece of track or a "diy type" one made out of a piece of copper wire inside a ceramic tube or ....,.

In any case, with black probe firmly attached to ground, follow-the-path from battery positive terminal to some PCB pad or track where said +12V should reach.

Clearly they are not reaching the fuse block, so that path is actually straight and simple.

Another possible culprit might be some kind of connector which lost contact or melted open inside.