TROUBLESHOOTING (Continued)

TM- 9-4910-663-34 Table 2-5. TROUBLESHOOTING (Continued) MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION CR12. Connect positive lead of ohmmeter to + terminal of rectifier assembly and negative ohmmeter lead to each AC input terminal in turn, and check for very high resistance indication in each case. Replace rectifier assembly CR9 through CR12 if resistance indication in range of 0 to 1000 ohms is obtained. Step 6. Repeat resistance checks of step 5, except with ohmmeter leads reversed. Check for very low resistance indications. Replace rectifier assembly CR9 through CR12 if open circuit indication is obtained. Step 7. Disconnect lead from - terminal of rectifier assembly CR9 through CR12. Connect negative lead of ohmmeter to- terminal of rectifier assembly CR9 through CR12, and connect positive ohmmeter lead to each AC input terminal in turn. Check for very high resistance indication in each case. Replace rectifier assembly CR9 through CR12 if resistance indication of 0 to 1000 ohms is obtained. Step 8. Repeat the measurements of step 7, except with ohmmeter leads reversed. Check for very low resistance indication. Replace rectifier assembly CR9 through CR12 if open indication is obtained. Step 9. Reconnect leads disconnected in steps 5 and 7. Set circuit breaker switch CB1 to ON position. Using AC voltmeter, measure AC voltages between terminals X1 and X4, and between terminals Hi and H4 of transformer T6 as DC VARIABLE POWER SUPPLY 0-32 VDC control is rotated over its full range. AC voltage should vary over range of 0 to 36 volts at terminals Xl and X4, and over range of 0 to 130 volts at terminals H1 and H4. If voltage between terminals H1 and H4 is normal but not voltage is obtained at terminals Xl and X4, replace transformer T6. If voltages at both measurement points are not normal, replace transformer T5. 2-22