Maintenance Manual
3
FRONT ASSEMBLY
The Front Assembly includes the speaker, PTT key button, Monitor button.
Microphone and Speaker
The microphone mounts directly onto the main PCB board. The microphone receives audio through the
hole in the front housing.
The speaker mounted onto the front housing, and connects to the main PCB board through the solder wire.
REAR ASSEMBLY
The Rear Assembly provides a die-casting frame for main board and sub-board. The antenna connects to a
SMA type connector that is mounted to the top of the frame.
The circuit of MAIN board of PZ-S series radio consists of the Audio/Logic circuitry (which controls the
functions of Radio) and the RF circuitry.(which decides the communication quality and performance) The
circuit of sub board consists of battery connectors and fuse for protected the main circuit.
CIRCUIT ANALYSIS
AUDIO/LOGIC SECTION
The Audio/Logic circuit consists of logic circuitry and audio receiver/transmitter circuitry. The
Audio/Logic circuit is common to UHF and VHF models. A single microprocessor on the board controls
the operation of the radio. The processor scans the control switch and issues commands to the RF board.
The Audio/Logic circuitry consists of primarily of the followings.
Microprocessor
Personality EEPROM
Audio signal processor
The schematic diagram is described in Fig . The first sheet contains all input/output connection for
the board. And the second sheet contains logic circuitry and audio signal circuitry.
