Common issues and solutions:
No standby light - Power board
Has standby light but doesn't turn on: power switch, power board, or main board
Turns on and screen blinks: Power board and/or sustain boards (Plasma TV), inverter (LCD TV), LEDs (LED TV), CCFL bulbs
Frozen logo or slow in channel changing: main board
Lights up but no display: main board, TCON, and/or panel
"Ghosting", fluctuating picture: TCON or panel
Vertical lines: Bad tab bonds, TCON ribbons, or TCON
Horizontal lines: panel
In some models, installing a good TCON into a TV with a bad panel could damage the TCON!
Repairing LEDs or CCFL bulbs requires removing the panel. Along with vertical and horizontal lines, bad tab bonds, and ghosting, it may be more cost effective to buy another TV.