Amp not turning on

[sfbadger]

Having a problem with a long-time set-up, there's been no changes to the system.

I get 12V at the power terminal when the car is off, the remote wire gets 0V. So far so good.

When I turn on the radio, I get 10.5V at the remote terminal, but only 4.5V (?) at the power terminal, amp does not come on.

Then I applied external 12V to the power terminal, the amp switched on and played normally. All I had to do was briefly touch the external 12V to the terminal and it would stay on. If I switched off the ignition and turned it back on, the amp didn't turn back on. I did this about a half-dozen times.

The last few times I tried it, the amp would turn on when I applied external power, but wouldn't stay on when removed, the sound would quickly fade out and the amp would turn off. If I maintain external 12V, it works properly.

Since power seems to be working as it should, I'm guessing my 20+ year-old amp has given up the ghost, but I thought I'd see if there was something I was missing.

Nothing appears wrong (no obviously blown capacitors).

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[BOOMINGRANDPA 5,000+ posts]

yeah i'd buy a new amp tell us what it is what u power with it well help u replace it.. #1 check all fuses, check ground make wure it's not loose has no rust under it.. i've had same wire in my car for 14 yrs if yours is old too check ends of power and ground wire make sure it's not corroded, make sure remote turn on wire isn't loose.. if wires and fuse look ok let us help u shop., we know what all the deal are..

 

[poolman966554]

10.5v on remote terminal seems low tbh. Just to be clear, with the vehicle off, you get 12V from amp positive to amp negative ; but with ignition ON, you get 4.5V from amp pos to amp neg???

Have you ensured that your meter was still set for DC volts? i find it very odd that your power wire is reading 4V unless you have a loose battery connection, ground, or fuse connection..