Technical Manual
Table Of Contents
- Vocoder and Controller Boards Detailed Theory of Operation
- Introduction to This Section
- General
- Vocoder Board
- Controller Board
- Switching Regulator
- RX Signal Path
- TX Signal Path
- Controller Bootstrap and Asynchronous Buses
- Vocoder Bootstrap
- SPI Bus Interface
- Universal Connector and Option Selects
- Keypad and Display Module
- Controls and Control Top Flex
- Controller Memory Map
- Vocoder Memory Map
- MCU System Clock
- DSP System Clock
- Radio Power-Up/ Power-Down Sequence
- Notes
- Secure Modules
- Disassembly/Reassembly Procedures
- Troubleshooting Procedures
- Troubleshooting Charts
- Troubleshooting Waveforms
- Troubleshooting Diagrams
8-9
Troubleshooting
Leak Areas
Before repairing any leak, read all applicable area repair paragraphs.
This will help to eliminate unnecessary disassembly and reassembly of
a radio with multiple leaks. Troubleshoot only the faulty seal areas
listed in the “Pressure Test” section, and, when multiple leaks exist, in
the order listed.
NOTE: Before reassembling the radio, always install a new
main seal o-ring, and new seals in the defective area.
Housing 1. If a leak occurs at the lens, universal connector, casting/housing
interface, or PTT/Ratt button area of the housing, replace the
housing. Referring to the Disassembly/Reassembly Procedures:
a. Remove the housing assembly from the radio.
b. Discard the housing assembly and main seal o-ring.
c. Install a new main seal o-ring around the casting assembly.
d. Install a new housing assembly to the radio.
e. Inspect the main seal for proper seating.
f. Observe carefully to ensure that the main seal o-ring is not
pinched between the housing and the casting.
2. If the leak occurs at the control top area, remove the knobs, knob
inserts and antenna in order to determine the leak location:
a. Conduct the Pressure Test.
b. Identify the leak location.
Antenna Bushing Seal 1. Referring to the Disassembly/Reassembly Procedures, remove the
housing assembly from the radio.
2. Remove and discard the antenna bushing seal.
3. Inspect the housing seal surface for debris or damage. Remove any
debris and replace housing if damaged.
4. Install new antenna bushing seal.
5. Install a new main seal o-ring around the casting assembly.
6. Reassemble the housing assembly to the radio.
7. Inspect the main seal for proper seating. Observe carefully to
ensure that the main seal o-ring is not pinched between the
housing and the casting.
Controls Seal 1. Referring to the Disassembly/Reassembly Procedures, remove the
housing assembly from the radio.
2. Remove the speaker bracket screw.
3. Remove the speaker bracket.
4. Disconnect the controls flex from the universal connector.
5. Disconnect the controls flex and backer from PTT area of the
housing assembly.
6. Referring to the Basic Service Manual (68P81089C80), Chapter 6,
remove the frequency knob, frequency insert, secure lever,
lightpipe, volume knob, volume insert, and o-ring.