My guess is that it's the bulb. My family has the 52HM85 and has had it since boxing day of 2005. Here's instructions on how to check how many hours are on the bulb (I pulled this from another site awhile ago):
[remember 2004 TV's end in 4 like 52HM84 while 2005 TV's end in 5 like 52HM85 or 52HMX95, etc]
"Douglas T, the instructions for checking lamp life are correct as I have validated it on my set. Here they are again.Step 5 is the only part different on the 2005's.
For the 2004 models:
With TV turned on:
1. Press "mute" on the remote - 1/2 mute appears on the screen
2. Press "mute" on the remote again - mute appears on the screen
3. Press "mute" on the remote and hold the mute button -
4. Press the "Menu" button on the TV's front panel. "S" will appear in the upper right corner of the screen.
5. Press the "Menu" button a second time and the "S" will disappear. On the left side of the screen you will see "RCUT" followed by two numbers.
You are now in the service mode.
6. Press "9" on the remote and you will access the diagnostics page. In the right hand corner is the lamp time in hours.
7. Press "power" button on remote to exit the menu and power off the TV.
CAUTION: Do not use the up and down volume keys on the remote in this menu as it can alter the data and can be dangerous.
For the 2005 models:
With TV turned on:
1. Press "mute" on the remote - 1/2 mute appears on the screen
2. Press "mute" on the remote again - mute appears on the screen
3. Press "mute" on the remote and hold the mute button -
4. Press the "Menu" button on the TV's front panel. "S" will appear in the upper right corner of the screen.
5. Press the "Menu" button on the remote and the "S" will disappear. On the left side of the screen you will see "RCUT" followed by RCUT
ADDR DATA BINARY
224DH 00H 00000000B.
You are now in the service mode.
6. Press "9" on the remote and you will access the diagnostics page. In the right hand corner is the lamp time in hours.
7. Press "power" button on remote to exit the menu and power off the TV.
CAUTION: Do not use the up and down volume keys on the remote in this menu as it can alter the data and can be dangerous.
"