3-15. RF SECTION, TROUBLESHOOTING.
via front-panel connectors, no internal wires
If problems are detected from the general
need to be disconnected during this opera-
which indicate faults within the rf module Al or
3-21. Whenever disassembling the test set
its subassemblies, proceed as follows:
or its components, refer to the illustrations
1. Turn off power and remove the retain-
of Section 6 (IPB), for location of mounting
ing screws from the. rf module. Lift the
screws, and placement of the components.
module from its chassis connector, leaving
Normal soldering and maintenance. tech-
the three rf cables attached to their jacks at
niques are employed for disassembly of the
the side of the module. Rotate the rf mod-
equipment. During replacement of any part,
ule to pemit access to its printed circuit
tag all wires removed, and check that they
board assembly. Make a detailed inspec-
are reinstalled to their correct points.
tion of the connections from the three rf
Dress leads as nearly as possible to their
modules to the printed wiring board assem-
original positions, when replacing parts.
bly. If any are broken, repair and reinstall
3-22. REMOVAL OF DIGITAL PRINTED
the Al module. If this does not correct the
CIRCUIT CARDS. The four replaceable
test set malfunction, remove and reconnect
printed circuit-card modules of the test set
the module to its chassis connector via an
are mounted in the card cage behind the
extender cable assembly.
front-panel assembly. Removal of any of
2. Reapply power to the test set and per-
these cards consists of unfastening the card-
retaining bar and pulling the specific card
Refer to the rf module A1 PCB track wiring
from its mounting connector (by operating
diagram (figure 3-8) for identification of
the card insert/extraction levers).
test points and locations.
3-23. REMOVAL OF RF MODULE AND
3-16. When performing the trouble analysis
SUBMODULES. To remove the rf module
tests for the rf module Al, use stands rd rf
from its normal mounting position on the
practices of connection (shortest possible
chassis, first disconnect the rf cables con-
l e a d s , etc.). Some disconnection of leads
nected to its jacks. Then loosen the two
may be necessary during those tests; care
captivated hold-down screws, and lift the
should be taken to prevent damage to com-
module out of its chassis connector. Access
ponents or PCB tracks. Always remove
to the submodules of the rf module requires
power to the test set prior to unsoldering/
removal of its protective cover. Individual
soldering connections. For continuity
submodules can then be removed by discon-
checks, insure that power to the test set is
nection of their wires, and removal of their
off. When the trouble analysis tests for the
mounting screws. Exercise care when re-
rf module Al have been completed, check
moving or replacing submodules, to avoid
that all connetions have been reconnected
damaging connector contacts, or other com-
(if they were disconnected).
ponents in the process of replacing one sub-
3-17. BULK ITEMS CONSUMABLE LIST.
3-18. The only items that are consumable
3-24. REMOVAL OF CHASSIS ASSEMBLY
bulk items are solder and rags used inunsol-
FROM FRONT PANEL ASSEMBLY. For
dering and soldering of leads to components to
access to the front-panel controls, and to
make parameter measurements of table 3-3.
the power supply components of the test set, it
is necessary to separate the front panel and the
chassis assemblies. This is accomplished by
3-20. The test set is conventionally con-
removing the screws holding the chassis to
structed, and can be disassembled into its
the rear of the front-panel assembly. Normal
component modules, chassis, and panel
unsoldering techniques are used to discon-
using normal maintenance tools. Separa-
nect wires from any part being replaced.
tion of front panel from the case is accom-
plished by unfastening the four screws at
the front panel, and pulling the front-panel/
3-26. No special cleaning procedures are
chassis assembly out of the case. Since all
required for the test set.
connections to the test set circuits are made