The manual provides instructions on how to replace the TVA92's horizontal output subbing transistor, including steps for removing the top case cover and locating the transistor on the main circuit board. It also advises on suitable replacement transistors and warns against using the dynamic tests if a "Sub Bad" display is indicated, as this suggests a shorted subbing transistor.

• Brand: Sencore-tech-tips-212-replacing-the-tva92s-horizontal-output-subbing
• Model: TRANSISTOR
• Type: manual
• File size: 93.0 KB

Manual Overview

The manual for replacing the TVA92’s horizontal output subbing transistor provides detailed guidance on troubleshooting, diagnostics, and replacement procedures. The TVA92 includes a diagnostic test that detects a shorted horizontal output subbing transistor, indicated by a flashing “Sub Bad” message on the digital display during dynamic tests. If this error is displayed, the transistor must be replaced before conducting further tests. The manual emphasizes using an exact replacement from the Sencore Service Department due to the specific characteristics of the original transistor, such as higher power dissipation and lower conduction resistance, which contribute to its longevity and performance. However, suitable replacements like ECG2300, 28D1402, SK9476, and NTE2300 can be used temporarily. The replacement process involves removing the top case cover, locating the transistor on the main board’s metal heatsink, and replacing it without unsoldering parts. The manual warns against connecting dynamic test leads to the TV’s horizontal output transistor if a “Sub Bad” readout is present, as this indicates an internal circuit failure.

Quick Issues Covered

• Diagnose 'Sub Bad' error for shorted horizontal output transistor.
• Replace TVA92's horizontal output transistor without removing circuit board.
• Use schematics for locating TR24 on main board heatsink.

Overview

The document provides guidance on replacing the horizontal output subbing transistor in the TVA92, a component that may fail due to high power and heat. It includes instructions for locating and replacing the transistor, recommendations for suitable replacement transistors, and warnings about potential issues during the replacement process.

Specifications

Refer to the PDF for details.

Controls & Indicators

Refer to the PDF for details.

Installation / Setup

The setup for replacing the TVA92’s horizontal output subbing transistor involves several steps. First, remove the top case cover by disconnecting the Dynamic Tests Leads from the chassis, turning off the VG91, and unplugging the AC Power Cord to the TVA92. Then, remove six screws located at the front and rear, as well as four screws and moldings on both sides of the case. Gently push back the top of the front and rear edge molding, lift the top case cover up, and remove it. The horizontal subbing transistor is located on the main board just behind the Horiz Output Device Sub & Drive front panel control, on a large metal heatsink frame. To replace it, remove the screws on the small metal retainer holding the transistor, gently separate the transistor from the heat transfer pad, and lift it from the socket. Insert the replacement transistor firmly into the socket and screw the metal retainer clip back in place. The heat transfer pad can be reused and does not require heat sink compound.

Operation

The manual provides steps for replacing the TVA92’s horizontal output subbing transistor. First, remove the top case cover by disconnecting the dynamic tests leads, turning off the VG91, and unplugging the AC power cord. Then, remove the screws on the top case and edge moldings. Lift the top case cover to access the main circuit board. The horizontal subbing transistor is located on the large metal heatsink. Remove the screws on the metal retainer, gently separate the transistor from the heat transfer pad, and lift it from the socket. Insert the replacement transistor into the socket and secure it with the metal retainer.

Troubleshooting & Error Codes

Refer to the PDF for details.

Safety & Warnings

Do not connect the DYNAMIC TESTS Leads to the TV’s Horizontal Output transistor when a “SUB BAD” readout is seen in the TVA92’s Digital Displays. The readout indicates an internal circuit failure which will alter TV symptoms and draw higher than normal TV B+ current.

Download TRANSISTOR Manual (PDF – 93.0 KB)

Guide for replacing the TVA92's horizontal output transistor. Includes step-by-step instructions for technicians. PDF size: 93.0 KB.

• Brand: Sencore-tech-tips-212-replacing-the-tva92s-horizontal-output-subbing
• Model: TRANSISTOR
• Type: Manual
• File size: 93.0 KB

Overview

Brief overview of the product.

Specifications

• Key spec 1
• Key spec 2

Controls & Indicators

Control panel/button layout.

Installation / Setup

1. Step 1…
2. Step 2…

Operation

Basic usage, modes, cycles.

Troubleshooting & Error Codes

Safety & Warnings

• Important warning…

Downloads

Download TRANSISTOR manual (PDF)