Alternator Problem S5 Turbo

[Turbo II]

Last Friday, warning cluster lit up. Belt was fine but heard screeching sound when I revved it sometimes. Also under 1k rpms cluster lights went out, over it they came on. Drove it home removed alternator took it to Autozone and they said it was bad.

Took alternator to local shop that rebuilds them, they check it and said it was bad and I left it with them to rebuild. Picked it up today, installed it and it worked fine for about 5 mins and then lit up the warning cluster and showing up to 18V output at times.

Battery reads fine, car runs great, no squealing this time from the belt (was it trying to lock up before?), just the same over/under 1k scenario and putting out way to much voltage. It was putting out anywhere from 13 to a little over 14 volts before it flipped out.

Is it possible they I got a bad rebuild or is there another electrical problem I should look for?

[Turbo II]

Last Friday, warning cluster lit up. Belt was fine but heard screeching sound when I revved it sometimes. Also under 1k rpms cluster lights went out, over it they came on. Drove it home removed alternator took it to Autozone and they said it was bad.

Took alternator to local shop that rebuilds them, they check it and said it was bad and I left it with them to rebuild. Picked it up today, installed it and it worked fine for about 5 mins and then lit up the warning cluster and showing up to 18V output at times.

Battery reads fine, car runs great, no squealing this time from the belt (was it trying to lock up before?), just the same over/under 1k scenario and putting out way to much voltage. It was putting out anywhere from 13 to a little over 14 volts before it flipped out.

Is it possible they I got a bad rebuild or is there another electrical problem I should look for?