TM 9-4910-663-34
Table 2-5. TROUBLESHOOTING (Continued)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
connections, replace MILLIVOLT METER MILLIVOLT DROP meter M4.
If zero ohm indication is obtained for either ohmmeter connection, replace diodes CR13 and
CR14 on PC board assembly.
If normal indication is obtained with positive lead of ohmmeter connected to terminal 5 and
negative lead connected to terminal 10, but open indication is obtained with ohmmeter leads
reversed, replace diode CR13 on PC board assembly.
If normal indication is obtained with positive lead of ohmmeter connected to terminal 5, but open
indication is obtained when ohmmeter leads are reversed, replace diode CR14 on PC board
assembly.
NOTE
Millivolt meter must be recalibrated if any of resistors R22 and R23, potentiometers R20 and R21,
or diodes CR13 and CR14 are replaced.
17.
GENERATOR D-SENSING CIRCUIT
a.
GENERATOR D-SENSING SWITCH INOPERATIVE DURING TESTS OF EXTERNAL COMPONENTS.
Step 1.
With all controls set to preliminary positions listed in table 2-2, connect ohmmeter between
GENERATOR D binding post and REGULATOR D binding post. Check for zero ohm indication with
GENERATOR D-SENSING switch S40 set to ON position, and open circuit indication with switch
S40 set to OFF position.
Replace GENERATOR D-SENSING switch S40 if incorrect indications are obtained.
18.
AC/DC SYSTEMS EQUALIZER COIL CIRCUIT
a.
AC/DC SYSTEMS EQUALIZER COIL CIRCUIT INOPERATIVE OR OPERATES ERRATICALLY DURING TESTS
OF EXTERNAL COMPONENTS.
Step 1.
Set all controls to preliminary positions listed in table 2-2. Set AC/DC SYSTEMS EQUALIZER COIL
TEST switch S35 to ON position. Using ohmmeter, check for 40 to 50 ohm indication between
GENERATOR G+ and AC/DC
2-58
