ARMY TM 5-6675-238-14
MARINE CORPS TM 08839A-14/1
Figure 8-9. Power Supply
(4) press SPU ON switch-indicator to off (switch.
indicator goes out).
(5) Disconnect DVM test leads.
d. Modular Power Supply PS4 Voltage Adjustment.
Perform voltage adjustment of modular power supply
PS4 as follows:
(1) Connect DVM test leads to -15V and COM
test jacks.
(2) Press SPU ON switch-indicator to on (switch-
indicator lights).
(3) Adjust modular power supply PS4 voltage
adjustment for -15 (0.04)V.
(4) Press SPU ON Switch-indicator to off (switch-
indicator goes out).
(5) Disconnect DVM test leads.
e. Overvoltage Protector Z1 Voltage Adjustment.
Perform voltage adjustment of overvoltage protector Z1
as follows:
(1) Check that SPU ON switch-indicator is off
(switch-indicator is not lighted).
(2) Check that SPU wires are not soldered to
overvoltage protector Z1.
Test-Jack Locations
(3)
(4)
(5)
(6)
(7)
Connect an adjustable DC power supply to
overvoltage protector Z1 with a 150- to 400-
ohm, 10-watt resistor in series with the posi-
tive side of the power supply.
Connect a DVM across overvoltage protector
Z1.
Slowly adjust power supply until digital volt-
meter indication suddenly drops, designating
trip-point voltage. Overvoltage protector Z1
trip-point voltage should be +30.8 (±0.6)V, If
necessary adjust voltage adjustment to obtain a
+30.8 (±0.6)V trip-point voltage.
Disconnect DVM and power supply.
Solder SPU wires to overvoltage protector Z1.
f. Overvoltage Protector Z2 Voltage Adjustment.
Perform voltage adjustment of overvoltage protector Z2
as follows:
(1) Check that SPU ON switch-indicator is off
(switch-indicator is not lighted).
(2) Check that SPU wires are not soldered to
overvoltage protector Z2.
(3) Connect an adjustable DC power supply to
overvoltage protector Z2 with a 150- to 400-
ohm, 10-watt resistor in series with the posi-
tive side of the power supply.
8-95
