Optoma HD72 displays white circles when the picture is dark

Despite the relatively few hours on the lamp, the fact is it's over 5 years old. It is not uncommon for a lamp to age and be too weak to fire. Replace the lamp, you should be fine.

The problem is not over-heating. The Optoma HD72 has a known problem that Optoma won't advertise. The lamp driver is faulty. They simply have to replace the lamp driver. I purchased a spare lamp with my original purchase. I had the exact same experience as you at around 1200 hours on the lamp in ECO mode. I used the spare lamp. Same thing happened at about 1200 hours. I had a friend at Optoma. he confided to me the problem. I sent it in and they replaced the lamp driver at no charge. I got another 800 hours out of the first lamp and am now using my second lamp and have about 600 hours on it. The pic quality is so good with this projector (used Digital Video Essentials to calibrate) that I'll just order a bare lamp or two and use the existing lamp housings when I need a new bulb.

In most projector menus there will be an option to reset the lamp timer, it's usually under the "settings" area of the menu. Try resetting the lamp timer and the light should stop flashing.

Sounds like bulb to me best way to check is take it to a service centere and they will use a replacement or test bulb to find out for you , it may not be your bulb it may be your ballast circuit . ... regards Vortash

I had the same problem with flashing colors after playing for awhile. The following helped:
1. turn off bright mode from menu.
2. keeping the back side of the projector flat. I had it raised up about 3" on the backside before, not sure why but it worked fine when flat.
Hope these help you also.

I had this exact same problem. I have changed bulbs gotten 1000 or so hours from new bulb, changed the lamp driver and gotten about 600 more hours from new lamp driver. New lamp cost me $350, lamp driver cost me $120. Then I read on a page to try and flip it right side up, because I had it ceiling mounted upside down. I flipped it right side up and it works perfectly and has been working perfectly for 2 months now. I know it sounds stupid, but it actually worked for me, and it costs you nothing to try it. For some reason, gravity effects this unit.

The board under the mainboard plugs into the top board like a cartridge. You have to disconnect all the cables from the mainboard then pull up on board to detact it from bottom board then you should see lamp driver in the back. Make sure hands are clean from static. Good luck.

The projector is sensing the amp draw from the bulb and shutting down due to out of spec draw...replace the bulb.

Mine did the same thing. The bulb is used up...replace the bulb. That fixed mine, working great again.

Most problems with the lamps are covered in the manuels for these projectors , however none user technical difficulties are not .. ie where it is needed to open the unit not recomended to the untrained as a screwdiver in the wrong place can cause irepairable harm let alone death ?
To check if it is your bulb simply take the unit to an engineer for an estimate usually free at least you will know whats wrong and can go from there .. and if you do have a working bulb an ebay replacement is probably the cheaper conclusion to your problem ... regards Vortash