Amp Cutting Out

[blown_volvo850r]

My amp has been cutting out during the summer when it's hot out and I'm running it full blast. But the last day or two it's been cutting out at volumes that are barely audible, and in 70 degree weather. It's a JL 500/5...any advice?

[Volv0wn3d]

My amp has been cutting out during the summer when it's hot out and I'm running it full blast. But the last day or two it's been cutting out at volumes that are barely audible, and in 70 degree weather. It's a JL 500/5...any advice?

do you have a remote turn on lead or does it just sense the signal?

[POOKDIZZLE]

Need more info as to what it's running, gauge of wire for power and ground etc. Also how is the amp mounted?

[blown_volvo850r]

It's on a remote lead to the EQ. Head unit flips on, EQ turns on, amp turns on. I looked at it last night and the low ohmage light was turning on, and the power light would turn off for a few seconds, then turn back on. Then the low ohmage light would come on, and so forth. It was awful last night and today, even at inaudible volume it would kick off. It's running my entire system...fronts, rears, and sub. It's never been a problem and it's been set up like this for over four years. The amp is mounted like this:

I wonder if it's my alternator going out. Seems like when I really get on the throttle and let off, it turns back on.

[BEJinFBK]

Have you put a meter on the power terminals of the amp while it's doin' this?

Have you unplugged the inputs and checked the amp with another source?

How long has it been installed? Have you got a cap? Could it be TU?

What have you got for speaker impedences? How many on each channel?

I don't wanna sound critical, but could the over-impedence light be correct?

Questions, Questions, Questions...

[blown_volvo850r]

I haven't checked squat. I don't work 'til 5:30pm today so I'm gonna yank it out and check everything. With as rough as the roads are around here, it could just be something knocked loose. The amp has five fuses in the side of it, and one of them could be out. I don't think it's an installation/wiring problem. It was done professionally by Goodman Radio in NJ and has worked flawlessly up until now.

[paulr]

I'm hard pressed to believe it's the alternator - by the time your system voltage gets low enough for the amp to cut out (in a properly wired system) you should have other visible signs of electrical problems (dimming lights, hard starts, etc). If however some of these things are happening, alternator / battery could be the problem. Amps can and do go bad, especially when they're perpetually overloaded / overheated, as you were describing was happening during the summer. There's a real chance it could be your amp. Beyond that, just like a previous poster said - check the obvious - shorts on speaker lines, loose wires, validity of over-impedance light, etc. No magic to it, just start crossing things off the list.

In situations like this, I typically first check the ground and hot lines, using something high-load like an inverter or a halogen spotlight. a +12V on a DMM with no current flow doesn't tell you much, a loose connection will carry full voltage under no load, but will have problems when the current is high. After checking the supply wires, I hotwire the amp on (+ to REM). If I can, I use a separate audio source, such as a CD player with 1/8" to RCA plugs. Then I go 1 channel at a time, looking for problems. This generally allows me to locate WHERE the problem is in a few minutes. You may not know if it's a short / blown speaker / etc, but you can figure that out later.

If this sounds like too much of a PITA, you could always take it back to the shop that did it and go "WTF"? Perhaps they'd look it over for free or a nominal fee, and with any luck they won't exaggerate the problem to try to sell you new gear.

Hope you get it fixed!