Applicable to:

The following information will help you to keep your projector working efficiently and help to achieve the maximum working life for the lamp. It also offers useful information about how and why some projector issues occur.

Switching the projector on and off

The projector should be shut down as indicated in the user manual, using the red power button on the remote control. The mains power supply should not be removed until the fans have stopped and the projector is in standby mode. If the power supply is interrupted before the projector has shut down correctly, this will almost certainly result in premature lamp failure.

Some projector models have a backup power supply that will apply cooling to protect the lamp in the event of a mains power failure. As such, some users may use this feature as a means of turning off the projector. The lamp is still vulnerable to vibration whilst hot and may become damaged. It is therefore still considered good practice to allow the lamp to cool fully before moving the projector. Even where a projector is promoted as not needing to be shut down before disconnecting from the mains power supply, it is still best practice to follow the normal shut down procedure.

Generally, projectors operate more efficiently if it is only powered on during the time that it is expected to be in use. If the projector is switched on and off every 30 minutes can reduce the lamp life. After shutting down the projector, you should wait at least 10 minutes before switching it on again to allow the lamp to come down to room temperature.

Filters

To ensure the projector operates reliably, it is crucial to clean and/or replace the air filters. It is recommended that the filters are checked and cleaned after 100 hours of use or once a month. Depending on the environment in which it has been installed, the projector filters may need to be checked and cleaned more frequently. It is essential that maintenance is carried out, as blocked or partially blocked filters will dramatically reduce the amount of cooling air which is carried to the lamp and the optical engine. This will generally result in a reduced lifespan of the product or premature failure of the lamp and/or projector.

Please refer to the projector user manual for more information about maintenance.

General lamp failure

Although it is anticipated that a projector lamp will continue to operate satisfactorily throughout its working life, occasionally a lamp may fail before that anticipated time has elapsed. The projector lamp is a consumable item, and even with proper use and maintenance, a small portion of lamps may fail before their expected lifespan has elapsed. Neither the life expectancy nor the performance of a lamp can be guaranteed, and its duration will depend to some extent on the conditions under which it operates.

Usage lamp failure

As a projector lamp ages, the ends of the two electrodes within the strike chamber cavity gradually erode, and the gap between them slowly increases. Erosion of these electrodes will occur every time the lamp lights. Eventually, a point is reached where the projector power unit can no longer supply the amount of current required by the lamp to strike and maintain the arc between the electrode tips. At this stage, the performance of the lamp will begin to deteriorate, and the issue will present itself as significantly reduced image brightness, flickering, cutting out after startup or failing to light at all. When this occurs, the lamp has reached the end of its useful working life and needs to be replaced.

The LAMP REPLACE indicator may not have illuminated at this time. This is because it is linked to a counter rather than the state of the lamp itself. When you replace the lamp, you must also reset the lamp counter in the projector menu.

Please refer to the projector user manual for more information about resetting the lamp counter.

Temperature related lamp failure

It is very important to shut down the projector correctly after use. When the power off command is sent by the remote control to the projector, the lamp extinguishes but the fans continue to run until the lamp has cooled sufficiently and the projector goes into standby. If the fans stop before the lamp has cooled, the glass temperature could rise to the point where failure of the lamp is possible.

Two factors that will result in high glass temperatures are incorrect shutdown procedures and blocked or partially blocked air filters. It is essential that the projector be shut down in accordance with the user manual in order that the cooling fans reduce the lamp temperature sufficiently.

The hottest part of a working lamp is the strike stem that contains two electrodes. If the airflow to the lamp is restricted in any way, the temperature rises around the strike chamber, which is enough to soften the glass. The usual consequence of this is that the pressure inside the strike chamber, as high as 200 atmospheres, pushes outwards at its weakest point and causes a bulge or swelling in the stem. The stem itself is pulled off its axis so the strike area moves away from the focal point of the reflector. This issue presents itself as significantly reduced image brightness, flickering, cutting out after startup or failing to light at all.

Elevated temperatures can also generate micro-cracks in the stem, allowing air to enter the vacuum. These cracks grow rapidly, and after a very short time the integrity of the structure is compromised. This will result in a shattered stem.

Any mains voltage interruption or power cut, however short, would produce these kinds of issues unless a backup power supply was incorporated to cover this eventuality.

Lamp life

Lamp manufacturers generally specify lamp life as the Median, rather than the Average Life. Median signifies middle, and it is not what most people think of as an average!

Median Life is the number of hours that have elapsed when 50% of a sample is still working. For example, the Median Life of 100 lamps would be calculated once the 50th lamp in the sample had failed.

If the specification for a lamp was 2000 hours, at least 50 of the lamps in the sample should still be working after this time had elapsed in order for the Median Life value to be valid.

Average Life would be calculated by recording the number of hours that each lamp was lit before failing, then dividing the total number hours by the number of lamps in the sample. Depending on the sample size, the Average Life could be higher or lower than the Median Life; there is no relationship between these values.

It is not possible to deduce from the lamp specification how long a lamp will last. It must also be understood that the brightness of the lamp will be reduced with use, over time.