Table 4-13. Troubleshooting Engine % RPM NO 1 and NO 2 (AVIM).

TM 55-4920-413-13&P j. Engine % RPM NO 1 and NO 2. (1) Connect frequency counter to connector NO 1 pins C (HI) and D (LOW), using two leads and adapter. (2) Set ENGINE % RPM NO 1 CAL/NOR switch to CAL and HI/LO switch to HI. (3) Set ON-OFF-SIM ONLY switch to SIM ONLY. Fre- quency counter will indicate between 1308 and 1362 Hz. If not, perform Troubleshooting Table 4-13. (4) Set ENGINE % RPM NO 1 HI/LO switch to LO. Fre- quency counter will indicate O. If not, perform Troubleshoot- ing Table 4-13. (5) Set ENGINE % RPM NO 1 CAL/NOR to NOR and adjust ENGINE % RPM NO 1 variable control from fully CCW to fully CW. Frequency counter indication will vary from O to 1830 Hz minimum. If not, perform Troubleshooting Table 4-13. (6) Set ON-OFF-SIM ONLY switch to OFF. (7) Disconnect leads from connector NO 1 pins C (HI) and D (LOW) and connect to connector NO 2 pins Y (HI) and Z (LOW). (8) Repeat (2) through (6) above, except use ENGINE % RPM NO 2 controls. Table 4-13. Troubleshooting Engine % RPM NO 1 and NO 2 (AVIM). NOTE Before performing troubleshooting, remove Frequency simulator A3 board and reconnect using extender board. Trouble Probable Cause Remedy HI-CAL % RPM indicates no NO 1 – U5 pin 7(61,342 Hz ± 27 Hz) First check loops 44 (-) and (3 HI) Frequency Output U13 pin 7 (61,134 Hz ±27 Hz) NO 1 for 1335 Hz ±27 Hz and check U15 pin 7 (HI), U14 pin 7 (HI), U13 pin 7 (HI), U5 pin 7 (HI). Figures 4-9, 4-10, FO-3, FO-5, or replace A3 board. LO-CAL NO 1 – (S11) Replace defective components A3 Frequency greater than 0 HZ NO 2 – (S13) board, Figures 4-8, 4-9, FO-3, FO-5, or replace A3 board. NOR-FULLY CCW NO 1 – (R5) (R14) (R17) Replace defective components A3 Frequency greater than 0 HZ NO 2 (R6) (R30) (R27) board, Figures 4-8, 4-9, FO-3, FO-5, or replace A3 board. NOR-FULLY CW NO 1 – (R5) (Q2) (Q7) (Q12) (U18) NO Frequency Output NO 2 – (R5) (Q3) (Q8) (Q13) (U2A) NOR-Frequency Trim Resistor out of tolerance NO 1 – (R4) NO 2 – (R23) Replace defective components A3 board, Figures 4-8, 4-9, FO-3, FO-5 or replace A3 board. Replace defective components, Figures 4-8, 4-9, FO-3, FO-5, or replace A3 board. Frequency out of tolerance after NO 1 – (R3(C4) (Q7) (R18) Replace defective components, trim resistors checked or replaced NO 2 – (R24) (C13) (Q8) (R31) Figures 4-8, 4-9, FO-3, FO-5, or replace A3 board. Low Amplitude effecting NO 1 – (U18) (C7) (R15) Replace defective components, Frequency NO 2 (U2A) (C18) (R28) Figures 4-8, 4-9, FO-3, FO-5, or replace A3 board. 4-21