Problem with 75 914 Alt

[kslanders]

my alt started making a load squealing noise so i replaced it. my new one dose the same thing. it stops if i disconnect it from the board. i think it may be the regulator. any one got any ideas. thanks

[Dave at Pelican Parts]

Put a vacuum hose up to your ear and use the other end to hunt for the location of the squeal. It could be the belt, the alternator, or any other moving bits. It's unlikely to be the regulator, but I suppose a regulator turning on and off again rapidly enough might possibly sound a little like a squeal? (The stock regulator has points in it like a relay does, which get opened and closed when the voltage goes up and down.)

--DD

[djpateman]

Check for a loose, mis-aligned or glazed belt. Disconnecting the regulator should kill the ability of the alternator to produce current, hence the load on the belt disappears as does the squeal of the belt.