USAcoustics Amplifier Problem

[NCState98]

Installed a system recently, my USAcoustics 2200 amp and just a 10 inch pioneer sub in a homemade "stealth box". Listening up until the time I get to the apt, leave an hour later and the amp isn't working at all. Later inspect and the "protection" light is automatically lit when I send power to the amp.

Any ideas off the top of anyone's head? This amp worked fine for years pushing a large Ground Zero sub, so I know this pioneer is no problem for it. What else would "protection" mean, other than overdrawing current from the amp, etc?

[96firebird311]

Thermal, but I doubt it because it was playing fine for an hour.... then cooled and then never kicked back on. Could also mean under/over voltage input, but again, I doubt it for the same reason. I don't know man.. that's a toughy... Maybe re-wire your Pioneer sub for a higher impedance just to see what happens?

You might think about opening it up for a visual inspection. I had this OLD Coustic amp that I put in my wife's car. Played fine for several days, then stopped. Protection light just light right from the start. After a little troubleshooting, I decided to open it up and take a look around. Holy cow. Fried components everywhere...and for seemingly no reason.

[NCState98]

I was thinking about pulling it out. I'm an electrical engineer and I'm pretty stumped about what caused the problem. It worked fine bridged in a 2ohm load pushing 600+ watts to the Ground Zero.

Since it worked fine until the time I turned off the car, and only acted up after restarting the car and flipping the remote switch (wired in line with the radio power antenna lead), I'm wondering if some power surge fried a component?

I'll check it out, any other ideas welcome.

[dmw319]

my guess is blown speaker outputs. ive seen this being the problem on about 90% of protection problem.

[NCState98]

What would cause that, and how could I bench test? I'm not sure what the internal resistance of the speaker outputs should be, but the resistance across the terminals (with the speaker hooked up at 4ohms, is 3.6 ohms. I've also checked the voltage at the amp and it seems fine.

[Big Tymer]

heat or ground..... yes ground can do it....

[Big Tymer]

i had a problem on one install, where with a multimeter, i could touch the pos and ground wires to it directly, it would say 12.5 volts

but with them connected to the amp and with it powered on.... using the multimeter to check power at the amp, it was only 5 volts..... i redid the ground and it then worked..

[NCState98]

Good call, I'll investigate my ground. I quickly tested 12.6V at the amp with the car turned off, but I should check with the vehicle running and amp remote turned on.

[NCState98]

All seemed fine in the car, but I've removed the amp and hooked it up to a small 12V power supply inside to bench test and no protection light :D I'm gonna install it again after my trip to FL and we'll see what happens.