Servicing Major Subassemblies - Motorola SABER Manual

II. SERVICING MAJOR SUBASSEMBLIES
A. Baseplate
• All repairs to the baseplate assembly can, and
should, be made with the radio chassis inside the
radio.
• After the slotted-spanner nuts are loosened, the
baseplate is held in place by the power contact
screws.
• The retainers holding the slotted-spanner nuts in
place are not reusable. Replacement of the retain-
ers requires special insertion procedures; refer to
the instruction sheet provided with the slotted-span-
ner nut kit.
• The O-ring portions of the elastomer seal must be
fully seated on the threaded bushings before the
baseplate is reassembled (the bushings are part of
the housing assembly).
B. Housing Assembly
• The housing assembly includes many parts that are
not replaceable or repairable.
• The insulator on the universal connector can, and
should, be replaced if the old insulator has been
torn. When replacing the insulator take care to keep
it out of the main seal O-ring's seating area.
• The PTT lever can be replaced by prying out the old
part with a soft plastic tool. The plastic housing
around the lever may be damaged if a harder tool is
used.
C. Control Top Panel
• The control top panel is fastened to the frame by the
on/off/volume and frequency switches, and two self-
tapping screws; it should be removed from the frame
only if absolutely necessary. If repair is required,
always start the screws into the control top panel by
hand before tightening them with a torque wrench;
this will help avoid cross-threading and stripping of
the plastic panel.
• The on/off/volume and frequency knobs are 2-part
kits; each kit consists of a knob and an insert. Once
an insert is removed, it cannot be used again; there-
escutcheon. A new frequency knob and insert must
be used each time this change is made.
NOTE
There are different detent washers for even or odd
numbers of switch positions; see the appropriate
exploded view parts list.
D. LCD/Front Shield Assembly
• The LCD assembly can be replaced on SABER II
and III radio PC board assemblies, but the instruc-
tions on the replacement kit's instruction sheet must
be strictly followed.
• The microphone boot must be properly oriented and
seated in the front shield before the microphone is
pressed into place.
E. Backshield Assembly
• Before removing the backshield, ensure that all sta-
tic electricity safeguards are in place.
• For best results, loosen/tighten all four screws light-
ly before loosening/tightening any single screw com-
pletely.
• The backshield screws are held captive in the shield
after being loosened.
F. Circuit Boards and Modules
• All modules plug into sockets on the main circuit
board.
• Some modules are fastened to the main board and
frame with screws; remove these screws before
attempting to unplug a module. Never substitute any
screw.
• Several of the modules are designed to be removed
with a standard DIP extractor tool (OK-1 or equiva-
lent). Always use the extractor tool when removing
these modules to avoid damaging their leads.
• Some modules have guide pins to assist in insertion
or removal. Pressure may be applied to these guide
pins to aid removal of a module if, and only if, it is
distributed evenly over all guide pins on the module.
Applying all the force to a single guide pin will cause
severe damage to the module.
• The U900 module is not serviceable