Table 4-8. Troubleshooting FUEL QUANTITY NO 1 or NO 2 (AVIM).

TM 55-4920-413-13&P e. Fuel Quantity NO 1 and NO 2. (1) Connect digital voltmeter to connector NO 1 pins G (HI) and H (LOW), using two leads. (2) Set FUEL QUANTITY NO 1 CAL/NOR switch to CAL and HI/LO switch to HI. (3) Set ON-OFF-SIM ONLY switch to SIM ONLY. Dig ital voltmeter will indicate between 6.08 and 6.18 vdc. If not, perform Troubleshooting Table 4-8. (4) Set FUEL QUANTITY NO 1 HI/LO switch to LO, Digital voltmeter will indicate between -0.1 and +0. 1 vdc. If not, perform Troubleshooting Table 4-8. (5) Set FUEL QUANTITY NO 1 CAL/NOR switch to NOR and adjust variable control fully CCW. Digital voltmeter will indicate between –0.1 and +0.1 vdc. If not, perform Troubleshooting Table 4-8. (6) Adjust variable control fully CW. Digital voltmeter will indicate .63 vdc minimum. If not, perform Troubleshoot- ing Table 4-8. (7) Set ON-OFF-SIM ONLY switch to OFF. (8) Disconnect leads from T1 connector NO 1 pins G (HI) and H (LOW and connect to connector NO 2 pins G (HI) and H (LOW). (9) Repeat (2) through (7) above, except use FUEL QUANTITY NO 2 controls. Table 4-8. Troubleshooting FUEL QUANTITY NO 1 or NO 2 (AVIM). NOTE Before performing troubleshooting, remove DC simulator A4 board and reconnect using extender board. Trouble Probable Cause ^Remedv. Fuel Quantity CR1, C3, Ul, R8, T2, R9, Cl, First check loops 7 (+) and 8 ( -) for No HI-CAL VOLTAGE NO 1 – (R2) or input 15 vac ±.5 vat. Check T2 if no NO 2 – (R5) voltage. Replace defective compo- nents, Figure 4-6, 4-7, FO-2, FO-5 or replace A4 board. HI-CAL VOLTAGE Trim Resistors Remedy, use decade resistor box, Indication out of tolerance NO 1 – (R3) and replace malfunctioning NO 2 – (R6) components, Figures 4-6,4-7, FO-2, FO-5 or replace A4 board. HI-CAL VOLTAGE NO 1 – (R56) or (R9) Output of U1 should read between Indication out of tolerance after trim NO 2 – (R55) 11.9 and 12.1 at TP1, Figures 4-6, resistors checked or replaced (R3) 4-7, FO-2, FO-5 or replace A4 board. or (R6) LO-CAL VOLTAGE NO 1 – (S26) Replace malfunctioning components, Indication out of tolerance NO 2 – (S28) A4 Board, Figures 4-6,4-7, FO-2, FO-5. LO-CAL VOLTAGE NO 1 – (R12) Replace malfunctioning component Indication out of tolerance in NO 2 – (R13) A4 Board, Figures 4-6,4-7, FO-2, NOR-FULLY CCW FO-5 In NOR-FULLY NO 1 (R1) (R12) Replace malfunctioning components NO 2 (R13) (R55) A4 Board, Figures 4-6,4-7, FO-2, FO-5 NOTE Voltage checks are also listed on figure 4-7. 4-13