TM 11-6625-2948-14+P
(6) Replacement procedures for the unit are the reverse of
INSTRUCTIONS
the removal procedures.
(7) After replacing the unit, perform the operations proce-
Removal and replacement instructions for the instrument
are given in paragraph a. through j. Component locations
b. Removal and Replacement of AC Box Assembly 1A1
NOTE
Do not disassemble the instrument beyond
(1) Perform steps (1), (2) and (3) of paragraph 4-60.
the point at which the necessary repair or
replacement can be made. Perform the
(2) Remove the top cover of Signal Generator SG-1145/
applicable minimum performance tests after
URM.
any replacement procedure given below.
Certain pieces of hardware may be Glyptol-
(3) Loosen the setscrews that hold the shaft of the POWER
locked. Before removing these pieces of
ON switch.
hardware be sure to use the proper tools
so as not to damage the component.
( 4 ) Remove the three screws that mount the AC box
assembly 1A1 (fig. 4-6) to the rear of the chassis.
WARNING
( 5 ) Disconnect connectors from connectors 1A1J2 and
1A1J3.
BEFORE ATTEMPTING ANY DISASSEM-
BLY OR REASSEMBLY PROCEDURES
(6) Replacement procedures are the reverse of the removal
MAKE
SURE
THAT
THE
POWER
procedures.
SWITCHES ON THE MODEL MD-1075/
U R M AND SG-1145/URM ARE IN THEIR
OFF POSITIONS AND THE POWER CORD
H A S BEEN DISCONNECTED FROM THE
POWER SOURCE.
a. Removal and Replacement of Signal Generator SG-
(2) Remove the top and bottom cover of Signal Generator
1145/URM or Modulator MD-1075/URM.
SG-1145/URM.
(1) Set POWER switches on signal generator SG-1145/
( 3 ) Disconnect connectors 1A2P3, 1A2P4, and 1A2P5.
URM and Modulator MD-1075/URM to their OFF
Connectors
1A2P3
and
1A2P4
go
to
pushbutton
board
positions.
assembly 1A3 and connector 1A2P5 goes to high voltage
control board 1A4.
(2) Disconnect power cord B160833 from power source
and AC INPUT connector on Modulator MD-1075/URM.
(4) Remove the four screws that mount the transformer to
t h e chassis bottom and two screws that mount to the
(3) Disconnect power jumper cable B160826 from the
chassis rear.
AC INPUT connector on Signal Generator SG-1145/URM
and the AC OUTPUT connector on Modulator MD-1075/
(5) Replacement procedures are the reverse of the removal
URM.
procedures.
(4) Remove the four mounting brackets, B165654, and
d. Removal and Replacement of Pushbutton Board Assem-
associated hardware that attach the brackets to the signal
(5) Remove the instrument that is to be replaced.
4.30 Change 1