Panasonic TX-21RX20M-MALAYSIA

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Power Source : AC SINGLE 220-240 V, 50/60 Hz

Power Consumption : 86 W

Aerial Impedance : 75 Ω unbalanced

Coaxial type

Receiving System : 17 Systems

Receiving Channels :

VHF 2-12 PAL / SECAM B, K1

0-12 PAL B (AUST)

1-9 PAL B (N. ZEALAND)

1-12 PAL / SECAM D

1-12 NTSC M (JAPAN)

2-13 NTSC M (U.S.A.)

UHF 21-69 PAL G, H, I / SECAM G, K, K1

28-69 PAL B (AUST)

13-57 PAL D, K

13-62 NTSC M (JAPAN)

14-69 NTSC M (U.S.A.)

CATV S1-S20 (OSCAR)

1-125 (U.S.A. CATV)

C13-C49 (JAPAN)

S21-S41 (HYPER)

Z1-Z37 (CHINA)

5A, 9A (AUST)

rights reserved. Unauthorized copying and

distribution is a violation of law.

TX-21RX20M-

MALAYSIA

GP41Z Chassis

Video / Audio Terminal :

DVD

Y 1.0 Vp-p 75 Ω

0.7 Vp-p 75 Ω

AV 1, 2, 3

Video In 1Vp-p75Ω

Audio In Approx. 0.5 V, 47 kΩ

Monitor Out

Video Out 1Vp-p75Ω

Audio Out Approx. 0.5 V, 1 kΩ

High Voltage : 24.0 kV ± 1.5

at zero beam current

Picture Tube : A51QGA993X01

51.0 cm (21 inches)

Measured diagonally,

90° deflection

Audio Output : 20.0 W

Dimensions : Height:431mm

Width:596mm

Depth : 340 mm

Mass : 20.5 kg (Net)

Specifications are subject to change without notice.

Mass and dimensions shown are approximate.

Colour Television

Specifications

ORDER NO. MTV0701584CE

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This document outlines the service and maintenance procedures for the Panasonic TX-21RX20M-MALAYSIA Colour Television, which utilizes the GP41Z Chassis.

Function Description

The TX-21RX20M-MALAYSIA is a colour television designed for home entertainment, capable of receiving broadcast signals across various global standards and displaying them on a 21-inch cathode ray tube (CRT). It supports multiple video and audio input/output options, including DVD, and features a remote control for user interaction. The television incorporates a sophisticated signal processing system (VCT-IF IC601) for video and audio, an EEPROM (IC1101) for storing settings, and a dedicated audio amplifier (IC2301) for sound output. Deflection circuitry manages the electron beam to create the image on the CRT, while a tuner handles signal reception. Geomagnetic correction is also integrated to optimize picture purity in different magnetic environments.

Important Technical Specifications

Power Source: AC SINGLE 220-240 V, 50/60 Hz
Power Consumption: 86 W
Aerial Impedance: 75 Ω unbalanced, Coaxial type
Receiving System: 17 Systems, supporting:
- PAL/SECAM B, K1 (2-12)
- PAL B (AUST) (0-12, 28-69)
- PAL B (N. ZEALAND) (1-9)
- PAL/SECAM D (1-12, 13-57)
- NTSC M (JAPAN) (1-12, 13-62)
- NTSC M (U.S.A.) (2-13, 14-69)
- PAL G, H, I / SECAM G, K, K1 (21-69)
- CATV: S1-S20 (OSCAR), 1-125 (U.S.A. CATV), C13-C49 (JAPAN), S21-S41 (HYPER), Z1-Z37 (CHINA), 5A, 9A (AUST)
Video/Audio Terminal (DVD):
- Y: 1.0 Vp-p 75 Ω
- PB: 0.7 Vp-p 75 Ω
- PR: 0.7 Vp-p 75 Ω
Video/Audio Terminal (AV 1, 2, 3):
- Video In: 1 Vp-p 75 Ω
- Audio In: Approx. 0.5 V, 47 KΩ
- Monitor Out (Video): 1 Vp-p 75 Ω
- Monitor Out (Audio): Approx. 0.5 V, 1 KΩ
High Voltage: 24.0 kV ± 1.5 (at zero beam current)
Picture Tube: A51QGA993X01, 51.0 cm (21 inches) measured diagonally, 90° deflection
Audio Output: 20.0 W
Dimensions: Height: 431 mm, Width: 596 mm, Depth: 340 mm
Mass: 20.5 kg (Net)

Usage Features

The television offers a user-friendly interface with both panel keys and a remote control. Key features include:

Service Mode Access: A dedicated service mode allows technicians to perform detailed adjustments. This mode is accessed by simultaneously pressing the remote's RECALL (+) and the panel's volume down key. Different service modes (SERVICE 1, 2, 3) provide access to various parameters, including brightness, program position, and increment/decrement of selected items.
Picture Adjustments: Users can adjust brightness, contrast, and other picture settings through the on-screen menu. For service, specific adjustments like White Balance (Low Light and High Light), CRT CUT OFF, and Focus are available.
Deflection Adjustments: The manual details procedures for adjusting vertical and horizontal centering and amplitude, as well as EW (East-West) adjustments, V-Sym, V-LIN, Trapezoid, Upper/Lower Corner, Angle, and Bow corrections. These are crucial for maintaining proper image geometry.
Purity Adjustment: This feature ensures that the electron beams correctly land on their respective colour phosphors, preventing colour contamination. It involves using purity magnets and a Helmhortz device.
Geomagnetic Correction: The television includes a geomagnetic circuit that can be adjusted to compensate for the Earth's magnetic field, which can affect picture purity.

Maintenance Features

The service manual emphasizes safety and provides detailed instructions for maintenance and repair:

Safety Precautions:
- Always use an isolation transformer when servicing the "hot chassis."
- Observe original lead dress, especially in high-voltage circuits.
- Ensure all protective devices (insulation barriers, papers, shields) are properly installed after servicing.
- Discharge the anode of the picture tube before handling.
- Perform leakage current checks (cold and hot) to prevent shock hazards.
- Be aware of the 25.0 kV potential present during operation and exercise extreme caution.
- Use only specified picture tubes to prevent X-Radiation.
- Do not touch the SW-Board without the back cover when power is on.
- Avoid touching hot parts or hot and cold parts simultaneously to prevent electric shock.
- Do not short-circuit hot and cold circuits.
- Connect instrument earth to the earth connection of the circuit being measured.
- Disconnect power plug before removing chassis.
Service Position for E-Board: Instructions are provided for safely positioning the TV and removing the A-Board for easier access during service.
Adjustment Procedures: Comprehensive steps are outlined for various adjustments, including:
- +B Voltage Confirmation: Checking DC voltages at specific test points (TPA 15-20).
- High Voltage Measurement: Confirming EHT (24.0 ± 1.5 kV) and heater voltage (6.3 V RMS ± 0.24) using calibrated meters.
- Purity Adjustment: Detailed steps involving purity magnets and a Helmhortz device to ensure accurate colour display.
- Convergence Adjustment: Procedures for static and dynamic convergence using 4-pole and 6-pole magnets, and YHC, YV, XV adjustments.
- CRT VRS Adjustment: Setting deflection yoke tilt and CY magnet for optimal CRT performance.
- Terrestrial Magnetism Circuit Confirmation: Adjusting the geomagnetic DAC to correct for environmental magnetic fields.
- Focus Adjustment: Adjusting the focus VR for the best picture clarity.
- Deflection Adjustment/Confirmation (50 Hz & 60 Hz): Detailed procedures for V-CENTER, V-AMP, H-CENTER, H-AMP, EW, V-Sym, V-LIN, Trapezoid, Corner, Angle, and Bow adjustments using monoscope and crosshatch patterns.
Lead Wiring and Connections: Diagrams and instructions for proper wire dressing and connections, highlighting critical safety points like anode lead handling and avoiding contact with other parts.
Parts Locations: Exploded views and diagrams indicate the location of mechanical and electrical components, aiding in identification for replacement.
Replacement Parts List: A comprehensive list of replacement parts, including resistors, capacitors, diodes, transistors, ICs, coils, transformers, and connectors, with important safety notices for components marked with an exclamation mark. This ensures that only manufacturer-specified parts are used for safety-critical components.