Table 4-15. Troubleshooting Engine Oil Press NO 1 and NO 2 (AVIM).

TM 55-4920-413-13&P 1. Engine Oil Press NO 1 and NO 2. (1) Connect equipment as shown in Figure 4-10, connec- tion A for connector NO 1. Do not disconnect equipment con- nected in Figure 4-1. (2) Set ENGINE OIL PRESS NO 1 CAL/NOR switch to CAL and HI/LO switch to LO. (3) Set precision oscillator for 6.00 Vrms at 400 +/- 10Hz. (4) Set ON-OFF-SIM ONLY switch to SIM ONLY. If digital voltmeter does not indicate between 3.447 and 3.735 vac, perform (a) through (d) below. If still defective, perform Troubleshooting Table 4-15. (a) Set autotransformer, dc power supply (A2), and precision oscillator to OFF. (b) Remove oil pressure board A2 (Figure 4-11 and reinstall, using extender board). (c) Set autotransformer, dc power supply, and precision oscillator power to ON. Allow equipment to sta- bilize and most importantly: maintain the precision oscil- lator output level at 6.00 Vrms throughout these tests. (d) Adjust RS (Figure 4-11) for a 3.591 vac in- dication on digital voltmeter (out NO. 1). (5) Set ENGINE OIL PRESS NO 1 HI/LO switch to HI. Digital voltmeter will indicate between 2.770 and 3.058 vat. If not, perform Troubleshooting Table 4-15. (6) Set ENGINE OIL PRESS NO 1 CAL/NOR switch to NOR and adjust ENGINE OIL PRESS NO 1 variable control from fully CCW to fully CW. If digital voltmeter does not in- dicate from more than 3.447 to less than 2.770 vat, perform ad- justments (4) (a) through (c) above and 6 (a) and (b) below. (a) Turn ENGINE OIL PRESS NO 1 variable con- trol fully CCW. (b) Adjust R1 (Figure 4-11) for a 3.591 vac indication on digital voltmeter. Table 4-15. Troubleshooting Engine Oil Press NO 1 and NO 2 (AVIM). NOTE Before performing troubleshooting, remove oil pressure simulator A2 board and reconnect using extender board. Trouble Probable Cause Remedy LO/NOR Fully CW NO 1 – (R5) First check loops 61( +) and 14 (-) indication out of tolerance NO 2 – (R22) for 15 vdc and then NO 2 loop 40(+) for 15 vdc. Check loop 3 for -15 vdc. Replace defective components, Figures 4-11, 4-12, FO-4 FO-5, or replace A2 board. LO/NOR Fully CW NO 1 – R3, R4, R5, U1, L3, S6, S7 Replace defective components, ) indication out of tolerance after (Front Panel) Figures 4-11, 4-12, FO-4, FO-5, or adjustment (R5) or (R22) NO 2 – (R2) (R21) (R22) (U2) (L2) replace A2 board. S4/S5 (Front Panel) LO/CAL Fully CCW NO 1 – (R1) Replace defective components, indication out of tolerance NO 2 – (R18) Figures 4-11, 4-12, FO-4, FO-5, or replace A2 board. LO/NOR Fully CCW NO 1 – (R3) (U1) Replace defective components, indication out of tolerance after NO 2 – (R2) (U2) Figures 4-11, 4-12, FO-4, FO-5, or adjustment (R1) or (R18) replace A2 board. LO/CAL NO 1 – (R9) Replace defective components, indication out of tolerance NO 2 – (R26) Figures 4-11, 4-12, FO-4, FO-5, or replace A2 board. LO/CAL indication out of ENG OIL PRESS NO 1 Replace defective components, tolerance after adjustment (R9) HI/LOW switch R8, R2, C5, C6, C7, Figures 4-11, 4-12, FO-4, FO-5, or or (R26) U4 ENG OIL PRESS NO 2 replace A2 board. HI/LOW switch R25, R19, C11, C12, U4 HI/CAL indication out of tolerance NO 1 – (R7) Replace defective components, NO 2 – (RX) Figures 4-11, 4-12, FO-4, FO-5, or replace A2 board. HI/CAL indication out of tolerance NO 1 – R6, R3, U1 Replace defective components, after adjustment (R7) or (R24) NO 2 – R23, R20, U2 Figures 4-11, 4-12, FO-4, FO-5, or replace A2 board. NOTE Check input voltage to (A2) board from (A1) board before troubleshooting (A2) board. Voltage checks also listed in Table 4-17, using figure 4-10 connections. 4-26 Change 1