Filament supply short in CRT Tv.

Introduction

This tutorial is designed to guide you through diagnosing and fixing a filament supply short problem in a CRT TV. Understanding these issues is crucial for anyone interested in TV repair, particularly for older CRT models. By following these steps, you can troubleshoot and potentially resolve filament issues effectively.

Step 1: Identify the Problem

• Visual Inspection: Start by inspecting the CRT TV for any visible signs of damage, such as burnt components or discoloration on the PCB (Printed Circuit Board).
• Power On the TV: Carefully power on the TV and listen for any unusual sounds that might indicate a short circuit.
• Check the Fuse: If the TV doesn’t power on, check the internal fuse for continuity. A blown fuse could indicate a short circuit in the filament supply.

Step 2: Use a Multimeter for Testing

• Set Up the Multimeter: Adjust your multimeter to the resistance (ohm) setting.
• Test the Filament Pins: Locate the filament supply pins on the CRT neck and measure the resistance:
  • Connect the multimeter probes to the filament pins.
  • A very low resistance reading may indicate a short circuit.
• Inspect Related Components: Check nearby components, including resistors and capacitors, for signs of damage or failure.

Step 3: Trace the Circuit

• Follow the Filament Circuit: Using the schematic diagram of the CRT TV, trace the filament supply circuit. Look for any components that may be shorted or damaged.
• Check for Shorts: With the multimeter, check each component in the circuit for shorts. Pay special attention to:
  • Diodes
  • Transistors
  • Capacitors

Step 4: Replace Faulty Components

• Identify Faulty Parts: Once you have pinpointed any faulty components, make a list of what needs to be replaced.
• Purchase Replacement Parts: Obtain the necessary replacement parts from a reliable supplier.
• Installation: Carefully desolder the faulty components and solder in the new ones, ensuring proper connections and orientation.

Step 5: Test the Repair

• Power On the TV Again: Reconnect the TV and power it on to check if the issue has been resolved.
• Monitor Performance: Look for normal operation and monitor for any signs of overheating or failure.
• Final Inspection: Conduct a final visual inspection to ensure everything is secure and there are no loose connections.

Conclusion

By following these steps, you should be able to diagnose and repair a filament supply short in a CRT TV. Always prioritize safety when working with electrical components, and consider consulting professional help if you encounter complex issues. If the problem persists after your repair, it may be time to explore more advanced troubleshooting or seek expert assistance. Happy repairing!