User's Manual

GMH Series VHF Radio Maintenance
BK RADIO Page 5-3
4. Inspect for corrosion at the terminal.
5.2.2 Cleaning
A. Using a clean, lint-free cloth lightly moistened with soap and water only, remove the foreign matter
from the equipment case and unit front panel. Wipe dry using a clean, dry, lint-free cloth.
B. Using a hand controlled dry air jet (not more than 15psi), blow the dust from inaccessible areas. Care
should be taken to prevent damage by the air blast.
C. Clean the receptacles and plugs with a hand controlled dry air jet (not more than 25psi), and a clean,
lint-free cloth lightly moistened with soap and water only. Wipe dry with a clean, dry, lint-free cloth.
5.2.3 Repair
This section describes the procedure along with any special techniques for replacing damaged or defective
components.
5.2.3.1 Connectors
When replacing a connector, refer to the appropriate PC board assembly drawing and follow the
notes to insure correct mounting and mating of each connector.
5.2.3.2 Crystal
The use of any other than a BK Radio crystal is considered an unauthorized modification.
5.2.3.3 Diodes
Use long nose pliers as a heat sink under normal soldering conditions. Note the diode polarity
before removal.
5.2.3.4 Integrated Circuits
Refer to Appendix A for removal and replacement instructions.
5.2.3.5 Wiring/Coaxial Cable
When repairing a wire that has broken from its terminal, remove all old solder and pieces of wire
from the terminal, restrip the wire to the necessary length and resolder the wire to the terminal.
Replace a damaged wire or coax with one of the same type, size, and length.
5.3 DISASSEMBLY & ASSEMBLY
The GMH radio has three major assemblies which contain the following circuit boards:
• Control Head Assembly (at the front of the radio)
Switch Board
Control Board
Option Board
• Core Assembly (in the extruded housing)
Systems Board
RX/TX Board