I have a 4805 and have gone thru 2 bulbs in 3-4 years. When I changed the bulbs I cleaned with vaccum the best I could and not the upper corners of the image are darkening

Bulb or lamp? either way this should help.

http://www.lumenarc.co.uk

are you sure its not the fan?
I supose its good to clean the fan and the inside ones a year.
dust gets in there.

The fan could be failing.

il get back to you about the humm

replace the colorwheel. if the colorwheel doesn't spin or spin properly, the lamp won't light. if the colorwheel is ok, you have a ballast problem.

your light tunnel has collapsed and needs replacing. you can get the part and do it yourself, or you'll have to send it in to an infocus authorized service center. try av solutions in ny. they're pretty good.

the light tunnel is collapsing and needs replacement. the part itself is relatively inexpensive, but you have to be careful if you want to replace it yourself. it's under the colorwheel, which is delicate. when you remove the top, front, and rear panels, remove the colorwheel (which is between the lens and the lamp) and carefully set it aside. there are 2 screws holding the light tunnel bracket in place. remove them and the bracket. pull out the pieces of the tunnel (little rectangles of mirror) and replace with a new one. reverse the steps to put it back together. by the way, you can get the part from any infocus authorized service center (check the infocus website for the one closest to you). part # 306-0095-01

If this is freestanding m/w:
1. disconnect from outlet
2. take the cover off.
3. light bulb located on right upper corner.

I’m happy to help further over the phone at https://www.6ya.com/expert/vitaliy_f406165329c75ede

check the wireing in the new bulb . My new one had the wires in the wrong holes like if there are 4 slots in the connector then my orignal was in slots 1 and 4 the new one was in slots 1 and 3 so I took the wire out and put it in the #4 slot and put it in and unpluged the machine and did a reset and restart and it came on green. Hope this helps.

I generally fix this by re-seating the bulb housing. Take it out and put it back in. Look for cracking at the base of the bulb on the mirrored surface. It could be a barely functioning bulb that isn't busted, but can't initialize. I would take it to a shop that has the same bub type in a housing and make a quick switch.

Manual is available here. Once open, you can save it by clicking on the save icon in the upper left corner.

To set date/time (page 3-6 in the manual):
1. Open the panel which covers the speed dial buttons on the right side, using the tab along the right edge (when open, you should see the Data Registration key in the upper left corner).
2. Press the Data Registration key.
3. Press the Set button 3 times.
4. Use the numeric buttons on the left keypad to enter month (2 digits), date (2 digits), year (4 digits), and time in 24 hour format.
5. Press the Set button 2 times.
6. Press the Stop button.

There are contacts inside the Livingstation that make contact with the heat sensor on the bulb. If you take the bulb out you will see them in the upper right corner of the bulb housing in the TV. These can become corroded resulting in a poor connection between the TV and the bulb. A poor connection will make the TV think it's over heating even if it's not. There are 3 contacts in the TV and 3 on the bulb. Clean these contacts with a lint free cloth and some alcohol on both the TV and the bulb, being careful not to let your fingers touch the bulb. If your hands are too big to reach inside the TV, rub a pencil's eraser over the contacts to clean them. When putting the bulb back into the TV, seat as firmly as possible, then tighten the upper right screw first.