I've got this old amp it powers up but no sound through it. There is a 3 pin molex slot I have no harness for I'm calling the pins 1,2,3 from left to right. The online manual shows the only two wires going in to the slot and does not designate which two pins to use. I'm currently using pins 1 and 2 that's gets the amp to power up should pin 3 be used also as another power pin or ground?

 

Amps require a constant +12V, a ground and a switched +12V lead for turn-on; if you know the ground you just have to figure out which is which for the 2 power pins.
(***FUSE the constant 12V wire!!)

 

The amp is labeled and I have the power and ground hooked up the three pin molex connecter is labeled as follows pin 1 ignition switch(its OK) diagram only shows 1 more wire coming from either the 2 pin or 3 pin it does not specfi. And labels this wire car stereo system control . to get the amp to power on you have to give pin 2 power and 3 pin is not hooked up at all. Some other forum from 6 yrs ago called the 3 pin illum printed on the circuit board but is not used. Maybe the amp is alrdy fried or the 3 pin needs to be utilized
But the amp does power on using 1 and 2 pins just no sound any old school guys out there remember this amp?

 

The GM-H series of amps all had that molex. Pin#1 is for ignition and Pin#2 is for the remote turn on lead (Blue/white) from your deck. Both can be connected to the remote on lead on the deck. Pin 3 had no connection.

 

OK thanks I guess its dead maybe the gain is turned all the way down I'll have to check on it but I think its fried

 

Too bad. It was a nice amp back in the day

 

I tried again this morning no sound left or right. I plan on making a self contained tool box
Radio/amp/power supply to use as a mobile test rig for subwoofer enclosures.