TM 11-6625-2709-40
Section Il. TROUBLESHOOTING PROCEDURES
2-4. General.
c. Connect the test set to a 27.5-volt dc power
source, and a 115-volt, 400-Hz power source.
The troubleshooting procedures are divided into
two parts. The first part (para 2-5 and 2-6) gives
d. Set the power switch on the control unit to
procedures to troubleshoot the aid box. The second
PWR.
part (para 2-7 through 2-9) gives procedures to
troubleshoot the control unit, the RMI, the OBS in-
dicator, and the test set.
junction of zener diode CR1 and resistor R8. Connect
the COMMON lead to the anode of zener diode CR1.
dc. If the indication is improper, replace defective
Because of the simplicity of the aid box circuitry,
zener diode CR1.
any trouble may he quickly isolated by the following
checks.
g. All other circuits in the aid box may be checked
by using the resistance chart in paragraph 2-6.
a. Remove the bottom of the aid box by removing
Remove all equipment connected to the aid box before
the six screws on the bottom of the aid box.
attempting resistance measurements. When an im-
proper resistance reading is obtained, refer to the
b. Connect P2 and P3 of the test set to the aid box.
schematic diagram in figure 1-5 to isolate the trouble.
Change 1
