Service difficulty report · Alternator · Cessna 172M

Difficulty date
September 17, 2007
Submitted
October 10, 2007
Operation
General aviation
Aircraft
N9531H
Make and model
Cessna 172M
Aircraft serial
17266205
Engine
Lyc O320*
Part
Alternator
Part number
DOFF10300JR
Part serial
G122718
Condition
Inoperative
Part time
46 hours
Stage of operation
NR
How discovered
9
Nature of condition
O
Precautionary procedure
O

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

THIS ALTERNATOR WAS OVERHAULED, OPERATED LESS THAN 50 HOURS, FAILED. THE STUD THAT HOLDS THE DIODE PLATE IN THE ALTERNATOR WAS BROKEN, AND THE SECOND STUD WAS LOOSE. THIS HAS BEEN AN ONGOING PROBLEM WITH OVERHAULS. WE ARE A SMALL SHOP, YET WE HAVE HAD MANY FAILURE WITH THIS PRODUCT IN THE PAST 2 YEARS. APPROXIMATELY 70 PERCENT OF THE OVERHAULS WE HAVE INSTALLED HAVE GONE BACK FOR WARRANTY. PROBLEMS INCLUDE LOOSE DRIVE PULLEYS, LOOSE HARDWARE, SHORT CIRCUITS, DEAD FIELD WINDINGS, DEFECTIVE BRUSHES. MY SUPPLIERS STATE THAT THEY HAVE HAD MANY COMPLAINTS ABOUT THIS REPAIR.

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