The most common problem with JVC LCD rear projection TV is bulb failure. Do not panic, this is normal after 2-5 years of use.
You can change the complete assembly or for less cost just change the bulb. Do not use Osram or other funny brand "rebuilt" or locally made bulb. Use a Philips replacement and all should be good.
Changing the bulb involves removing the lamp assembly and taking it apart like a puzzle and replacing the bulb. JVC are a little more difficult to do than most others because the wires on the original bulb are molded into the glass on the original bulb. Wires must be cut and stripped of insulation before connecting to the new bulb.
All JVC LCD Rear projections TVs use TSCL110 TSCL110U TS-CL110U Lamps.
HD-61FB97 HD-61FC97 HD-61FH96 HD-61FH97 HD-61FN97 HD-61G587 HD-61G657 HD-61G787 HD-61G887 HD-61Z456 HD-61Z575 HD-61Z575AA HD-61Z585 HD-61Z786 HD-61Z886
Check this out for all JVC models to identify the lamp and bulb. JVC Gallery