Kenwood TH-77A/77E Transceiver Diagrams

TH-77A/77E BLOCK DIAGRAM

The block diagram illustrates the overall architecture of the TH-77A/77E transceiver, dividing it into the TX-RX UNIT and the CONTROL UNIT. The TX-RX UNIT handles radio frequency transmission and reception, featuring components like RF amplifiers, mixers, filters (LPF, BPF, HPF), VCOs, and the SCU (Signal Control Unit). The CONTROL UNIT manages user interface, processing, and power, including the microcontroller (IC12), LCD display, key matrix, and audio amplifier.

Key sections within the TX-RX unit include:

TX-RX UNIT (X57-3740-00): Contains multiple sub-sections for different frequency bands (VHF, UHF) and signal processing stages (RF AMP, MIXER, MCF, AF AMP).
CONTROL UNIT (X53-3330-00): Houses the main processing logic, including a microcontroller (MPU/515148F), memory (SRAM), and interface logic.

The diagram shows interconnections between these units via various signal lines, indicating data and control flow.

TH-77A/77E SCHEMATIC DIAGRAM

The schematic diagram provides a detailed circuit-level view of the transceiver's components and their interconnections. It breaks down the functionality into specific modules and sub-circuits.

Control Unit Details:

Microphone Input: Connected via J1, with PTT, MIC, WMT, and WDT signals.
Speaker Output: Connected via SP.
External Speaker/Mic: Connected via EXT. MIC/SP J2.
Main and Sub Units: The schematic details the Main V.FO, Sub V.FO, Main HPF, and Sub HPF circuits, along with associated transistors (Q1-Q10), ICs (IC1, IC2, IC3, IC4, IC5, IC6, IC7), resistors, and capacitors.
DTMF/BEEP and AF AMP: Circuits for DTMF/BEEP generation and audio amplification are shown, utilizing ICs like IC2 (TC4086BF) and IC3 (TC4086BF).
Reset and Control Logic: Includes reset circuitry and various control signals (SCU, SMU, AFV, etc.) managed by IC12 (HD6407408-JBX).
Key Matrix and Display Interface: Shows connections for user input and the LCD display.

TX-RX Unit Details:

VHF VCO (X58-3740-00): Details the Voltage-Controlled Oscillator for VHF frequencies.
RF AMP, MIXER, MCF: Components for radio frequency amplification, mixing, and intermediate frequency filtering.
APC (Automatic Power Control): Circuitry to regulate transmission power.
Noise Amp: For amplifying noise signals.
TCSS UNIT (X57-3700-00): Likely related to Tone Squelch System.
Transistor and IC Designations: Numerous transistors (e.g., 2SC4117, 2SC4226, 2SC4093) and ICs (e.g., TC4086BF, TC74HC4066, TC74HC00) are specified with their part numbers and functions.
Component Values: Resistor (Rxx) and capacitor (Cxx) values are indicated throughout the diagrams.

Component Cross-Reference:

A table lists various components and their associated part numbers or designations, aiding in identification and replacement.

ICs: IC1 (TC4066BF), IC2 (TC4086BF), IC3 (TC4086BF), IC4 (TC4066BF), IC5 (TC74HC4066), IC6 (TC74HC00), IC7 (TC74HC4066), IC8 (TC74HC00), IC10 (TC74HC4066), IC11 (LC7585N), IC12 (HD6407408-JBX).
Transistors: Q1-Q22, including types like 2SC4117, 2SC4226, 2SC4093, 2SB526, 2SD1024.
Diodes: D1 (DS3232), D2-D13, D201-D212, including types like MA110, MA77, DA204U.

2011 PIV Information

The document references '2011 PIV' in relation to the TX-RX UNIT (X57-363X-XXI(RFV)). This likely pertains to a specific revision or version of the unit's design or components.

Component Identification Tables

Several tables provide mappings between component designators (e.g., IC201, Q201, D201) and their specific part numbers or manufacturers (e.g., W56760FP, 2SC4117/8L1, MA110).

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