TRAK MODEL 9100 MODULAR FREQUENCY/TIME SYSTEM
D-3
TM4400013
REV.
D
D-3 DC
POWER
SUPPLIES, A11 and A12
The Model 9121 DC/DC Power Supply, shown in Figure D-2, contains a red FAULT indicator and three green
power supply output voltage status indicators. The FAULT indicator illuminates if any of the three power
supplies voltages fall below a reference level. The appropriate green power supply indicators are normally on
and extinguish if a voltage drops below a reference level. The Model 9121 Power Supply is supplied with Model
9100 DC input versions. The DC and AC power supplies have different back plane power connections to avoid
damage if the wrong power supply is installed.
Figure D-3. Model 9121 DC Power Supply
D-4. POWER SUPPLY FAILURE
If a power supply fails, the FAULT indicator illuminates. To replaced a failed power supply module, proceed as
follows:
a) Remove DC power from the failed power supply. For example, if the power supply closest to the FSU failed,
remove DC power on the rear panel connector labeled DC INPUT A.
b) Before removing a failed DC power supply, check the condition of the fuse located in the fuse holder
associated with the DC power input connector. If the fuse if blown, replace with the same rating as specified
in Table D-3.
c) Reconnect DC power to determine if the failed power supply is operational.
d) If not, again disconnect DC power and loosen the four front panel screws securing the power supply to the
chassis.
e) Holding the power supply module handle, carefully pull on the handle and remove the power supply.
f) Install the power supply in the reverse order and reconnect DC power.
TRAK
SYSTEMS
FAULT
+5VDC
+15VDC
-15VDC
DC/DC P.S.