Piper Navajo PA-31 Service Manual page 714

PIPER NAVAJO SERVICE MANUAL
b. With switch turned ON, connect voltmeter
as shown in Step 2, Figure 11-12.
Make sure positive (+) and negative (-) voltmeter
leads are connected as shown.
c. If meter reads battery voltage,
disconnect lead at alternator
"F1" (field)
terminal.
1. If reading is still battery voltage, wiring is not defective,
and no more
wiring tests need be made.
2. If voltage reading is zero, the "NEG" and "FLD" leads are reversed.
Circuit trace will be burned open between points A-A, B-B, or C-C, Figure 11-14.
d. If meter reads
zero voltage, disconnect
lead at alternator "F1" (Field)
terminal,
and connect a jumper
lead from this lead to battery positive (+) post.
See Figure 11-13.
1. If meter now reads battery
voltage, the "POS" and "FLD" leads are
reversed. This misconnection
alone will not cause the circuit
trace to be burned
open.
2. If meter now reads backwards,
alternator field terminal
is connected
to regulator
negative terminal, the positive
line is connected to regulator
field
terminal, and regulator positive terminal
is connected to negative side of circuit.
Either the circuit trace will be burned between points C-C, D-D, or E-E, Figure
11-14, or the driver
transistor will be open. In either case, the driver bias re-
sistor will have been overheated.
e. If voltmeter reads
backwards, disconnect lead at alternator
"F1" (Field)
terminal.
1. If meter
still reads backwards,
the "POS" and "NEG" leads are
re-
versed. The circuit
trace may be burned between points C-C, D-D, E-Eor
F-F,
Figure 11-14. The transient
suppression diode will always be open or shorted.
2. If meter
now reads zero, the positive
line is connected to regulator
"NEG"terminal, the negative line is connected to the regulator
"FLD" terminal,
and the alternator "F1" (Field)terminal
is connected to the regulator
"POS" ter-
minal. The circuit trace will be burned open between points F-F, Figure
11-14.
For further assistance, follow the procedure in the
latest revision of DELCO-REMY Service Bulletin
IR-273 when troubleshooting circuits containing
this regulator.
Revised: 9/24/81
ELECTRICAL SYSTEM
Effectivity
DELCO
4B12