Testing Rectifiers (Positive) - Piper ARROW III Service Manual

11-11. TESTING RECTIFIERS (POSITIVE). (Refer to Figure 11-5.) Special test box tool C-3829 has been
developed to test the diode rectifiers without opening the "Y" connection as is necessary where the test lamp
method is used.
Due to the short leads at the "Y" connection, it is quite difficult to separate and reconnect them properly.
This tool, C-3829, will save much time and is accurate.
Insulate alternator from metal bench and plug tester tool C-3829 into a 110-volt supply. Connect the
alligator clip of tool C-3829 to the alternator "BAT" terminal and touch the bare metal of each of the positive
case rectifier lead wires in the heat sink at the rectifiers.
The meter reading for each of the rectifiers should be the same. Always contact the connection nearest the
rectifiers.
Do not break the sealing on the rectifier lead wire or on the top of the rectifiers. The sealing material is
used for corrosion protection.
The reading on the meter will indicate 1.7 or over for good rectifiers. Where two of the rectifiers are good
and one is shorted, the reading taken at the good rectifiers will show low. The reading at the shorted rectifier
will be zero. Cut the lead at the bad rectifier and the reading at the two good rectifiers will come up to normal.
Where one of the rectifiers is open, it will read low (1 amp or less) the two good rectifiers will show normal.
Revised: 2/13/89
CHEROKEE ARROW III SERVICE MANUAL
Figure 11-5. Testing Rectifiers (Positive)
2G22
ELECTRICAL SYSTEM