I have a HP 4260N Plasma TV. About 4-5 years old. A week ago the remote would not turn the TV on, and there was no volume. I contacted my cable company and thinking it might be a remote problem they had me reset the TV and the Cable Box. So now, the remote and TV are working correctly from an on/off perspective, but the picture is horrible. Very faint, no color or limited color, and a bit fuzzy. Is this the dreaded bad YSUS Board problem??

SOURCE: Our HP 50" Plasma TV needs a new Input mainboard

It is hard to find a company that will tell you where the parts come from. Most parts you cannot purchase in america.
Here is a website I would suggest that will help you at best!
Please copy and paste in your browser
http://h20141.www2.hp.com/hpparts/partsdirectory/catalog_solutions_AP.htm

SOURCE: HP Plasma TV - Lost Picture

Here's the number to HP case management 877-917-4380 ext.79, try this number and be firm that they need to fix this, I just had an HP plasma that was 3 yrs old replaced for free, no charge. Good luck

SOURCE: No picture, audio OK, HP PL4260N, outside HP's repair for common Problem

as its necessary to replace the y board if its faulty. try  www.partstore.com for cheaper price boards.

SOURCE: i have hd picture but no sound, tv says hdmi audio unavailable

I called Verizon and exchanged my STB from a QIP 6416 to a QIP 7216 and it solved the HDMI audio problem. This looks like the fix.

SOURCE: Looking for replacement circuit board for HP TV

On ebay for less than $100