Front Alternator Inoperative

[rick bell]

not only did age kill the diodes, but the front alt. coupl. broke, it would charge up to about 22v then blead back down (i'm assuning as it took on loads the coupling would give away(??)). may have been defective for a long time as i was always cycling the alt switches. is there any reason these coupling fail (new alts 150. ago)

[SkyMac]

Hi All

Just adding another solution to the thread for future reference, when I bought the plane in 2010 it had a rear alternator light illuminated during engine operations.

During the restoration I rebuilt the dual alt control, o/h both alternators, installed new regulators and so on. The old girl has been back in the air for over a year now and recently the rear light came again.

After hours of going through every terminal (which were replaced during resto except two) diodes checked, regulators checked and even sending the alt out for inspection (working fine). The light was still on, back to drawing board

So what did I find?

The battery lead that connects to the alternator ( yes one of the two not done during resto) had broken due to zero slack in length to handle engine vibrations. Judging by the wires almost all strands had been broken for years, the cable was being held in place by heavy gage heat shrink.

Refitted a new terminal - Light went out!

One more for the check list guys

Dave