Screen on my LG 42LH40 just went blank & is displaying series of light blue arches resembling planet rings, blue in color. Pip works fine when searching channels but every channel does not populate the main screen. Sound is fine too.any ideas out there?

Bud Martin

• 11361 Answers
• Posted on Nov 14, 2009

SOURCE: LG 26LG30 screen suddently went blank. Light flashing blue/red

There are two places to look for the problems, the backlight inverter board and the power supply. Look at the power supply first since it is easier to get to, look for burnt parts, bad capacitors, etc.
http://en.wikipedia.org/wiki/Capacitor_plague
Please post back what you find.

SOURCE: LG RZ42PX11 PICTURE PROBLEM.

I do not know who was helping you before but the problem you are having can be caused by three boards in the tv each by themselves or in combination. Those are the control board with part#6871QCH053G, the Y- board part #6871QYH036D or the Z-board part#6871QZH041B. Without being able to do voltage and signal measurements directly for you, the Z-board is likely the culprit here. But I will tell you that even experienced tv technicians find themselves swapping one or more of the boards until they fix the problem. I am assuming here of course that you have not had problems with your tv before. The part #s I have given you are for the improved boards that LG has assembled to take care of future similar problems and come with their latest training manual for technicians. God bless and good luck.