After a successful bypass, the PDF instructs how to use UV glue or high-temp tape to secure the cut ribbon cables so vibrations don't cause arcing later.
This is the most common failure point.
Modern LCD/LED screens have two sides (left and right). Each side has a series of copper traces and chips (COF - Chip on Film) that drive the horizontal lines. A common fault occurs when moisture or a power surge damages one side of the panel. This damaged side pulls the entire voltage line (usually the VGH or VGL high/low gate voltages) down to zero.
Based on the PDF's first chapter, ensure you have:
The Mainboard must send a signal to the PSU to "wake up" the high voltage rails. 3. Backlight Failures (Most Common) After a successful bypass, the PDF instructs how
If the TV has sound but no picture (the "Flashlight Test" shows an image), the LEDs are dead. Never replace just one LED bead; replace the entire strip Prevention:
After repair, go into the TV settings and lower the "Backlight" level to 70% to extend life. 4. Screen Bypassing (Cof/Gate Bypass)
This is used when a screen has "double images," "flickering," or "vertical lines" caused by a short inside the glass panel. The Tape Cut Method: LVDS/Ribbon cables going from the T-CON to the panel. Use a tiny piece of clear tape to block specific CLK (Clock) signal pins.
By blocking the "shorted" side of the panel, the "good" side can often drive the whole screen. COF Bypassing: By physically isolating the damaged side—either by cutting
If a side "Chip-on-Film" (COF) is burnt, technicians solder a "jumper wire" from a voltage point on the T-CON (like ) directly to the test point on the COF. 5. Common Voltage Reference Chart
If these voltages are missing on your T-CON board, the screen will stay blank: 12V (Main input) 20V to 30V (Gate High) -5V to -10V (Gate Low) 5V to 7V (Common voltage) 15V to 17V (Analog supply) Safety Warning:
Always unplug the TV before touching the internal boards. The Main Capacitor on the power board can hold 400V even when the TV is off.
If you'd like to dive deeper into a specific repair, I can help you if you tell me: Brand and Model Number of the TV. exact symptom After a successful bypass
(e.g., clicking sound, blinking LED code, or half-colored screen). Do you have a multimeter soldering iron ready to use? I can then walk you through the specific "Tape Cut" jumper points for your exact model.
By physically isolating the damaged side—either by cutting specific pins on the ribbon cable or removing the side tabs—the technician blocks the short circuit. The working side of the TV then functions normally. The result? A TV that was completely dead (or showing massive lines) now displays a perfect picture on 75% to 85% of the screen, with the isolated side going dark or showing white.
Warning: This is a physical modification. It is permanent. But for a TV destined for the landfill, it breathes new life into the unit.