I have a dark shadow square 3"x3" in the upper left corner of my screen. Any thoughts on the cause of this?

bro you should take it to the repairer,No other options you have. it can't be fixed by doing anything accept changing it's screen or repairing it, if it's possible

Goof proof...take a tape measure and measure from lower right to upper left of screen..or lower left to upper right. That'll give you your size.

I'm not sure, but I'm old enough to remember all the tv's were round. B&W 3 channels.
18" measured across. When they came out with square tv's someone came up with this measuring system..corner to corner.


Best to you.

Hello
Same problem for me. found a procedure to get back to Service Menu which works for HP 8600 :
https://h30434.www3.hp.com/t5/Printers-Archive-Read-Only/X476dw-doesn-t-boot-Help/td-p/5044674
1. Unplug the power cord (!)
2. Insert power plug while keeping power button pressed.
3. While the HP logo appears on the screen, keep the button pressed. The screen will go dark. KEEP THE BUTTON PRESSED for another 5-10 seconds.
4. Let go of the button. The screen remains black.
5. Push Home-Back-Home-Home button. The buttons are usually not visible, so refer to the manual, where they are on the touch screen. (Home is left of the upper left corner of the touchscreen, Back is left of the lower left corner)
6. A blue menu comes up, with four choices.
7. MENU on the lower right has a FULL RESET option.

Calibrate the control panel

Use the following procedure to calibrate the control panel:

1. Turn the device off.

2. Press and hold the # key and the C key.

3. Turn the device on.

4. When a small white square appears in the upper-left corner of the control-panel display, touch

the square with a stylus.

5. When a small white square appears in the lower-left corner of the control-panel display, touch

the square with a stylus.

6. Allow the device to finish the boot process.

Hope this helps.

Projection TV sets have several common problems listed below.

Problem #1) Convergence

Symptoms:

• Screen Looks 3D
• Colors wont align
• Screen may look distorted
• No Audio/Video - TV makes a chirping sound.

Problem #2 CRT Fluid has clouded over. Symtoms

• Dull looking video
• White looking video
• Halos around objects
• Red/Orange looking video

You can see some examples and find a fix here...

http://www.fixya.com/support/r2861467-solution_video_looking_whiteish_dull

I would check for dust particles before I attempted any type of repair on the unit.

Dust particles will appear as dark spots that are larger than the size of an individual pixel. It must first be determined if the particle(s) are on the LCD panels or the screen.

It's the light tunnel. The tunnel is a square tube made up of 4 mirrors glued together.

It looks like this from the side: |_| (with a piece on top too.)
When the glue breaks down, it shifts inside the little mirror holder. The shifted mirrors looks like this /_/ what you are seeing is the shadow of the tilted mirror tunnel.
ON the RCA's there's not a good fix.

RCA's response:
"Ok, well sadly they do not offer the light tunnel anymore, which is what you need. Sadly you would be rendered to get a whole new light engine assembly. That would be the D.N.D module, light tunnel,color wheel,optic spanner, and oci. mirror. Your best bet would be to search ebay for a broken engine and replace it that ways."

That is the ONLY response I got from them.

I took the set apart and found the 4 tiny mirrors. I will be attempting to epoxy them together. (The set is dead anyway, why not try?)

Had same issue with my LG so I trouble shot the issue by noticing the green square would disappear if I switched to dvd(HDMI-2 ) Or HDMI-3. Which lead me to believe it was being generated by my Xfinity box (HDMI-1. So I first rebooted box. With no success I then unplugged box all together. Tah Dahhh! Problem fixed. Hope this helps.

Thanks for the picture - that's a big help.
It looks you have the dreaded light tunnel collapse common to all LG DLP TV's. Inside the light engine there is a square tube made up of four mirrors. These mirrors deform and crack with the heat of the lamp. They fall down over the light aperture and cause a shadow of varying degrees. It is fixable now at a realistic price ( used to have to replace engine) as LG have made the parts available. It would take a competent tech around three hours to complete or if you are technically minded you could do it yourself. I hope this helps.
Hope Ya Fix It!

I have the same problem and now there is convergence problem with the entire screen, double images and ghosting ...i was told that some IC's are burned our ...etc..i'm waiting to see if they sell the entire board since the TV's are 10 years old... will let U know what i get as a response.