Jagged horizontal blue lines everywhere

What is the make and model, is it a HD TV?

Change the Tcon board and you should be back in business.

sounds like your panel is going bad. usually not economical to repair.

sounds like the flyback / power supply

Picture is reduced to a straight horizontal line across the center of the screen.

problem is caused by the loss of horizontal deflection signal. It is quite surprising that the entire unit is still working, since usually, a loss of H-Out will disable the entire set. Problem can be as simple as loose solder connection to a more complicated defective horizontal circuit. I would suggest havint it checked by a professional TV tech.

WHEN YOU HAVE A SOLID BLUE LINE THAT DOES NOT MOVE...YOU HAVE A DEFECTIVE PANEL...LIVE WITH IT OR REPLACE PANEL..NOT COST EFFECTIVE TO REPLACE PANE....JOE ACE

sounds like bad capacitors on the FMT board need replacing that is a common fault with the first generation DLPs There are 3 bad capacitors.

What is the make and model number of your set? I may b able to help you. desribe in more detail is the picture gone entirely and you only see colored horizontal lines on ablack screen?

Try changing tuner