RCA LCD TV L42wd22YX5 - Gets unusual signal to all inputs

You need to do some troubleshooting first since it can be any one or more of the boards that failed. Please read my guide below before DIY.
If you are going to DIY and have proper tools, electronics knowledge, and know safety precaution then please read on:

Basic LCD monitor and TV troubleshooting guide:
http://www.fixya.com/support/r5093881-lcd_flat_panel_tv_troubleshooting_guide
http://www.fixya.com/support/r6150077-basic_lcd_monitors_troubleshooting
http://www.fixya.com/support/r7406380-tv_training_manuals
Failed TV and Monitors: http://s807.photobucket.com/albums/yy352/budm
Learn about bad caps: http://en.wikipedia.org/wiki/Capacitor_plague
Parts: www.shopjimmy.com
Capacitors kit: http://lcdalternatives.auctivacommerce.com/Default.aspx he can make you a set of caps.
Or www.digikey.com, just make sure to use caps with low ESR, 105c, high ripple current and long life rating such as PANASONIC FM or FC series.
Please leave rating if it helps.
Please post back what you find.

Try to reset unit to factory defaults. There may be a button for that or a code to do it with. If nada available, contact mfg for the hidden code if one

Recommend opening it up and looking at the power board and see if there are any visible Bulged or leaking capacitors.
Bad caps are a major source of computer and LCD no post problems.
If you find em, then just find replacements with the same uF and voltage and solder them out/in.

We had the same problem. What we did was unplug our DVR box from Comcast to reset it and plugged it back in and the picture came back.

your mainboard is failing and will need to replace this company as well as many others do not sell part seperatly only at board level you can try shopjimmy.com or call a local shop to help you

Hi,
    According to the symptom the main power capacitor popped. Check and replace the capacitor, and your tv work fine again.
    Thanks for using fixya.

i had this happen last year, now my tv is messed up again. when we had the problem with the unusable signal, the tv repair shop told us it was the main motherboard that caused it. ended up paying $250.00 to have it fixed. Now, our tv is broke again, this morning turned it on, got the green light, then just started flashing red, hasnt worked any at all today, reset it and everything. My suggestion, if you can afford to buy a new tv, do it, because I called the repair shop again this morning about the new problem, they said after the 1 year warrentt from rca runs out all they do is tear up. My tv isnt even 4 years old, bought it at the end of 2007, now its tore up twice, going to purchase a samsung in the morning from brandsmart. Good Luck!

Hello Mike:

The issue that you are having is with your small signal board and it needs to be replaced, it sounds like the microprocessor on that board is getting locked up.

The problem is a blown fuse on the top side of the board. It is about 2 inches from the tuner. There is a label 7c32 on the board. The part is a 1206 surface mount fuse with a F on it. The F indicates it is .5 amp. The reason they are all failing is because they undersized the fuse. Replace it with a
F1455CT-ND at
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=F1455CT-ND

This fuse is a little bigger. You can check the data sheet at digikey to get a picture when you are looking for it.