Optima H30 warning

It's probably telling you that your bulb is nearing the end of its life. (At least it's doing its job -- half the time these things give you no warning at all.) So buy a replacement bulb for the day when the old one dies. You can turn off the annoying light by going into your set's menu and telling it you've just replaced the bulb. Be sure to do that again when the bulb actually dies and you replace it, so it doesn't give you a very early warning next time.

the lamp bulb or halogen lamp module has reached the end of its serviceable life, not because of any wiring problems. Low beam burns out first because it is on the most. If low beam is lost simultaneously in both headlights, I would check fuse first, then the headlight switch. If low beam is lost on one side only, it is almost always going to be due to the bulb or lamp module needing to be replaced. In that case, replace them in both headlights because the other one will be going kaput in short order, as well.
ceiling light

Hi Every single time I have had a failure of low beam in a headlight without failure of high beam, it has been because the lamp bulb or halogen lamp module has reached the end of its serviceable life, not because of any wiring problems. Low beam burns out first because it is on the most. If low beam is lost simultaneously in both headlights, I would check fuse first, then the headlight switch. If low beam is lost on one side only, it is almost always going to be due to the bulb or lamp module needing to be replaced. In that case, replace them in both headlights because the other one will be going kaput in short order, as well.Also if you already replaced the fuse and bulb check the headlight dimmer control switch.
Thanks for using Fixya.

The likeliest problem here may be a burned out or failed projector bulb. Most projectors will fail to power up at all when if the bulb is out. The HD20 user manual does not specify a red light as an error indication option however, generally amber.
User manual .pdf is located here (takes a bit to download for it's size), Projector Status Indicator instructions are located on page 40.
Here on the product page itself, an email to Optima support may be warranted given the red instead of amber error light.
If you had any messages recently indicating your bulb life was nearing it's end, again, this would be my first guess. Certain models of projectors do have a tendency of blowing through bulbs even before any warning message comes up. I had an experience with a certain brand/model that for the last 3 replacements has given only about 1/4 of the stated bulb life, so unfortunately it does happen.

Those photoconductors have a limited life and have to be replaced. The message is warning that it is near the end of its life and wants you to have one ready when it goes out. Most printers will prevent you from printing when it reaches the end of the service life, some will let you continue to print but you will get reduced image quality. Either way, you'll need a new one soon.

The transfer belt may have reached its life expectancy now. You need to replace the transfer belt soon. Hope this helps. If you need more assistance, leave a comment and I'll get back to it. Thanks.

When you replace the lamp, you need to reset the lamp counter as well. The procedure for this should be in the owner's manual. This counter is a guide only. Lamps have an expected lifetime and the message indicates that the lamp is nearing that lifetime. Once reset, the counter will again trigger the message once this new lamp reaches that usage time.

Dan

Replacing the fuser
When 80 Fuser life warning appears on the operator panel, replace the fuser soon. Make sure one is on order. See
Ordering a fuser for more information.
When 80 Replace Fuser appears on the operator panel, replace the fuser immediately.

......From the Lexmark users guide.....

if the fans come on and the lamp doesn't, it's the ballast or the colorwheel. if no fans either, it's the power supply. also, did you reset the lamp timer?

It is likely a warning that some major maintenance is coming due; for example, timing belt replacement, catalytic converter reaching end of life (typically 60,000 miles) or other. There is probably a procedure for resetting the warning without actually doing what is required.