TROUBLESHOOTING (Continued)

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