18.104.22.168 Direct-Wired PCB Removal/Replacement. All
Access to the assemblies and components within
electrical connections to this type of PCB are made by
solder connections at the point on the PCB where the
the six clamping catches on the front cover and
external wires attach. Direct-wired PCBs are used in the
removing the cover. When the cover is removed, a
following AN/SPS-64(V) equipments:
safety interlock switch is activated which disables the
high voltage power supply; the interlock switch may be
a. Azimuth Range Indicators IP-1282 and IP-1283
pulled outward to permit high voltage operation if
b. Receiver Transmitters RT-1240 and RT-1241
required for troubleshooting or alignment. Access to the
c. Switching Units SA-2139 and SA-2156 d. Video
modulator, magnetron and microwave circuits is
achieved by loosening the two captive screws on the
Use the following general procedure for removing and
control panel and swinging the panel outward until it
replacing direct-wired PCBs.
locks in its service position.
1. Set POWER switch to OFF at equipment unit
containing PCB to be removed.
2. Open equipment to gain access to the PCB
(access details are given in the first paragraph of the
(REGULATED) IS PRESENT IN THE
section devoted to each equipment, e.g., paragraphs
VICINITY OF THE MODULATOR
TUBE, HIGH VOLTAGE PCB AND
3. At each PCB wire connection (in turn):
MAGNETRON WHEN THE HIGH
a. Tag the wire with sufficient information to
VOLTAGE POWER SUPPLY IS
identify the connection point on the PCB.
b. Unsolder and disconnect the wire, taking
care to avoid applying excessive heat to
5.10.1 Troubleshooting Procedure
components and the PCB surfaces.
4. Note the PCB mounting position. Remove the
is facilitated by use of Troubleshooting Chart, Figure 5-
mounting hardware and withdraw the PCB.
2. Instructions for use
of the troubleshooting chart are
5. Locate the replacement PCB in the same
position and install mounting hardware.
6. Observing the connection points tagged on the
external wires, connect each wire in turn to the
THE POWER SUPPLY CONTAINED IN
replacement PCB and solder, taking care to avoid
RECEIVER TRANSMITTER RT-1240
applying excessive heat to components and PCB
UTILIZES A FLOATING COMMON
7. Replace access covers.
APPROXIMATELY -150 VDC WITH
RESPECT TO CHASSIS GROUND.
5.10 RECEIVER TRANSMITTER RT-1240
EXERCISE EXTREME CARE TO
AVOID CONTACT. DO NOT GROUND
THE FLOATING COMMON BUSS
EXCEPT WHEN, AFTER ALL POWER
HAS BEEN REMOVED FROM THE
X-band MTR). The information includes troubleshooting
instructions (5.10.1), removal and replacement
VOLTAGE MUST BE DISCHARGED
The locations of assemblies and major components
Figure 5-1. Schematic diagrams, parts list tables and
assembly drawings applicable to Receiver Transmitter
RT-1240 are contained in Section 6.2 of Chapter 6.