TM 55-4920-401-13&P
Table 4-9. Insulation Check Circuit Troubleshooting Table.
Malfunction
INSULATION CHECK meter cannot
be adjusted to read infinity when
FUNCTION SELECT switch is not in
INSUL position.
INSULATION CHECK meter reads
i n f i n i t y w i t h i n s u l a t i o n c h e ck
adapter jumpered and INSULATION
CHECK switch in either position.
INSULATION CHECK meter drives
t o z e r o e n d w i t h I N S U L A T I ON
CHECK switch in either position.
Probable Cause
a. INSULATION CHECK
meter
a. Defective insulation
check adapter.
b. Defective instrument
cable.
c. Resistor R26 or R27
o n r e s i s t a n c e a n d i n-
sulation check board
d. Defective FUNCTION
SELECT switch
e . D e f e c t i v e I N S U-
LATION CHECK switch
a. Resistor R30 or R32 on
resistance and insulation
check board
b. Defective FUNCTION
SELECT switch.
Corrective Action
a. Replace meter (37, figure
figure FO-8).
a. Repair or replace adapter.
b. Repair or replace cable
c. Replace defective resistor
(3, 6, figure 4-38).
d. Replace switch (32, figure 4-
37).
e. Replace switch (13, figure 4-
38).
a. Replace defective
resistor (5, 2, figure 4-38).
b. Replace switch (32, figure 4-
37).
4-11
