no charge,please help

[2.2 Turbo]

Ok so my alt. Starting making a whining noise like a supercharger and the voltage went down everytime I stop. When I take off again it will go back up ,make the whine sound. So I back in the moring to investagate, and now it doesn't make the sound and doesnt charge! So I had the old alt checked and the guy said it was dead. So I bought a new one put it on and still nothing. So I just need to know where to start like fuseable links or somthing. Thanks. Oh its a 84 daytona, 90amp alt, and its externally reg.

[turbopac]

check all connections make sure they are all good

[charger R/T]

You car should be wired very close to the diagram on the right.

First take a voltage reading on the big positive cable on the alternator with the engine not running. It should be almost the same as the battery.
Also I don't know what year cars used the rubber bushings for the alternator but if yours does make sure the ground cable running from the alternator case to ground is good.
The last 2 wires are the small field wires. These are what controls the charge voltage. One should have 12v+ on it with the key on. The other gets a varing ground from the voltage regulator.
The regulator also gets a 12v+ to the one terminal. Being its an older car with the external regulator they fail quite often and aftermarket ones fail even more then OEM.
Tim

[2.2 Turbo]

thanks guys, it was just the ground.... there wasnt one! so i put one on and it works.