TM   55-4920-413-13&P (6) Disconnect positive lead from loop 1 and connect to (8) Disconnect positive lead from loop 18 and connect to loop 19. Digital voltmeter will indicate between -33 and –41 loop 46. Digital voltmeter will indicate between 11.5 and 12.5 vdc. If not, perform Troubleshooting Table 4-6. vdc. If not, perform Troubleshooting Table 4-6. (7) Disconnect positive lead from loop 19 and connect to (9) Disconnect positive lead from loop 46 and connect to loop 18. Digital voltmeter will indicate between 11.5 and 12.5 loop 13. Digital voltmeter will indicate between -11.5 and vdc. If not, perform Troubleshooting Table 4-6. -12.5 vdc. If not, perform Troubleshooting Table 4-6. Table 4-6. Troubleshooting Power Supply Circuit (AVIM). NOTE Before performing troubleshooting, remove power supply Al board and reconnect using extender board. Trouble Probable   Cause Remedy No AC inputs to Al board Fuse F1, S1, T1 Transformer Replace  defective  components, Figure 4-4, 4-5, FO-1, FO-5, or replace Al board. 5 VFL NO 1 and NO 2 vdc reading NO 1 – (R3) (R3) or (R6) are Fixed Resistors use out of tolerance NO 2 – (R6) decade  Resistor  Box,  and  check  or replace, Figures 4-4, 4-5, FO-1, FO-5 or replace A1 board. 5 VFL NO 1 and NO 2 no vdc or NO 1 – CR1, C7, U1 Replace  defective  components, shows excessive reading after trim NO 2 – CR2, C8, U2 Figures 4-4, 4-5, FO-1, FO-5 or resistors (R3) or (R6) checked or replace A1 board. replaced 15 vdc reading out of tolerance CR4, R8, CR6, C6, C13 Replace  defective  components, Figures 4-4, 4-5, FO-1, FO-5 or replace A1 board. –15 vdc CR3, R7, CR5 Replace  defective  components, vdc reading out of tolerance C9, C10 Figures 4-4, 4-5, FO-1, FO-5 or replace Al board. 37 vdc CR4, CR6, C3, R8 Replace  defective  components, vdc  reading  out  of  tolerance C6, C13 Figures 4-4, 4-5, FO-1, FO-5 or replace Al board. –37 vdc CR3, R7, CR5 Replace  defective  components, vdc  reading  out  of  tolerance C9, C10 Figures 4-4, 4-5, FO-1, FO-5 or replace A1 board. 12 vdc NO 1 and NO 2 R19 Adjust  (R18)  or  (R19) vdc  reading  out  of  tolerance R18 if  defective  use  decade  resistor  box check or replace, Figure 4-4, 4-5, FO-1,  FO-5 12 vdc NO 1 and NO 2 NO 1 – Q2, U3, CR7, CR1O Replace  defective  components, vdc reading out of tolerance after NO 2 – Ql, U4, CR7, CR1O figures 4-4, 4-5, FO-1, FO-5 or trim resistors (R19) or (R18) replace A1 board. (R19) or (R18) checked or replaced 12 vdc NO 1 and NO 2 NO 1 – C14, C29, U3, C21, C19, Replace  defective  components, no  vdc  or  shows  excessive  reading C25,  R1O Figures 4-4, 4-5, FO-1, FO-5 or after trim resistors checked or NO 2 – U4, C28, C20, C18, C24, replace  A1  board. replaced C20, R9 -12 vdc R20 Adjust (R20) if defective use decade vdc  reading  out  of  tolerance resistor  box  and  check  or  replace, Figures 4-4, 4-5, FO-1, FO-5 or replace Al board. – 12 vdc U5, CR8, CR9 Replace  defective  components, vdc reading out of tolerance after Figures 4-4, 4-5, FO-1, FO-5 or trim  resistor  (R20)  checks  or replace Al board. replaced – 12 vdc C26, R23, C27, C25, C22, C23, Replace  defective  components, no vdc reading out or shows U5, R11 Figures 4-4, 4-5, FO-1, FO-5 or excessive  reading  after  trim  resistor replace A1 board. checked 4-9