How to Test Projector Lamp Is Bad

How to Test Projector Lamp Is Bad

Understanding how to test your projector lamp will help you keep your projector bright. This means figuring out what kind of lamp you need and opening the lamp cover yourself. 

Whether you have an overhead projector or one for backyard movies, you need the information I am going to present in this article.

There are some ways to know that that you have a bad projector lamp:

  1. Once vivid images now flicker and disappear
  2. The monitor has a few lamp hours left 
  3. The indicator light on the projector is lit

How to Test Projector Lamp Is Bad or Not in 6 Easy Ways

The projector lamp is the heart of the projector. It is the source of light, and its brightness is the most important factor in image quality. There are six ways to test your projector lamp:

  1. Check the brightness of the lamp by using a laser meter.
  2. Test the lamp with a flashlight.
  3. Use an infrared sensor.
  4. Use a light meter.
  5. Use a colorimeter.
  6. Use a spectrometer.

1: Check the Brightness of the Lamp by Using a Laser Meter:

A laser meter is a device that measures the amount of light emitted from an incandescent lamp. You can use it to find out how bright the lamp is.

To do this, you need to set the laser meter to measure in the area where you will be sitting and then put the meter on the lamp.

Then, move the laser meter around until the reading reaches zero, indicating that the light is as bright as it should be.

2: Test the Lamp with a Flashlight:

The bulb should shine brightly when the lamp is on. If it is not, there is probably something wrong with the bulb or the ballast.

Make sure the lamp is plugged into the correct outlet. There are two types of bulbs: compact fluorescent lamps (CFLs) and halogen lamps. CFLs have a screw base and are interchangeable with incandescent lamps.

Halogen lamps have a pin base and must be screwed into a socket with a threaded wall plate. A halogen lamp is usually much brighter than an incandescent lamp.

3: Use an Infrared Sensor:

An infrared sensor can detect the light emitted by the projector bulb. If the bulb doesn’t emit light, the sensor should still work.

An infrared sensor is a device that detects radiant energy in the form of heat. This energy comes from objects that are closer to the sensor than the object that you are trying to measure.

An infrared sensor can be used to detect the presence of a person or object in a room.

4: Use a Light Meter:

A light meter can measure the light output of the projector bulb.

When you purchase a new projector bulb, the manufacturer will provide you with a chart showing how much light a particular bulb produces. The chart lists the light output at different distances from the bulb.

You can then use this information to choose a bulb that will produce the correct amount of light for your room. 

5: Use a Colorimeter:

A colorimeter measures the color temperature of the light output. Color temperature refers to the color of the light that is produced.

6: Use a Spectrometer:

A spectrometer is a device that can measure the light spectrum and compare it to a standard. A spectrometer allows you to compare the light that is produced by a bulb to a specific standard.

The color of the light that is emitted by a projector bulb can make a difference in the way that the room appears.

For example, if the projector bulb is emitting light of too high a color temperature, the room will appear dim.

When you want to test your projector bulb to see if it is functioning properly, you should use a light meter and a spectrometer.

The brightness of the light that is emitted by a projector bulb can also have an effect on the appearance of the room.

How Does a Projector Bulb Work?

Projector lamps have an arc gap filled with ultra-high pressure mercury vapor. The lamp works by sending a current across this pressurized ARC gap. 

This current causes the mercury vapor to glow and the lamp to emit a very bright light. 

This bright light hits an LCD or DLP panel and produces the stunning images that projectors are known for.

How many years does a projector lamp last?

A standard projector lamp includes ARC or metal halide that contains ultra-high pressure mercury vapor within the envelope. 

Projector lamp life for this type of lamp is 1,000 hours, 1,500 hours, 2,000-3,000 hours, and 5,000 hours.

There are also lamps that use LED (Light Emitting Diode) technology and last significantly longer than standard metal halide lamps. 

Projector lamp life for this type of lamp is up to 60,000 hours, or 30 years.

A laser (light amplification by stimulated emission electromagnetic radiation) projector lamp has a life of 20,000 hours. This takes about 10 years or more if handled with care. 

How to tell if a projector lamp needs replacing?

Most projectors have an indicator light or a message indicating the end of the lamp’s life.

In such cases, you may not need a new lamp immediately, but it’s a good idea to purchase a spare lamp when you need it.

Another reason your projector lamp needs replacing could be due to color shifting.

If the colors look muddy when you turn on the projector, the bulb may not be putting out enough power to display accurate colors on the projector’s color wheel display.

One way to check this is to increase the brightness or color of your projector. If the room is as dark as possible and the projector is set to maximum brightness and the image quality is still poor, the lamp is out.

How to test a projector lamp with a multimeter?

Firstly, set your multimeter to check ohms or resistance. 

For digital multimeters, the display will flash briefly and show zero.

Firmly place one test lead of the multimeter into one contact of the lamp and the other test lead into the other contact. In a two-wire lamp, each protruding wire is a contact.

Whether the needle is moving or stationary (in analog meter). When moved, it usually stops at a resistance value between zero and 20 ohms.

A resistance reading means that the lamp has continuity or the elements are fine and should light up.

If the meter needle does not move, the lamp element is physically open. 

That is, the lamp is burnt out or physically broken. If so, it is time to replace the lamp. 

If using a digital multimeter, the number on the display should change to the lower resistance value. A broken lamp filament registers as infinite resistance.

What is projector lamp resistance?

Resistance, measured in ohms, determines the current in the circuit, assuming the voltage remains the same. 

No current flows through a load with infinite resistance. 

A load with no resistance will have infinite current flow (known as a short circuit). 

The LED’s resistance is close to 50 ohms and draws close to 0.25 amps in a 12 V circuit.

The projector lamp not turning on

There are several reasons why the projector will not turn on. If the projector does not turn on, please try the following:

  • Make sure the projector is properly plugged into a working electrical outlet.
  • Check the temperature light to make sure the device is not overheating and shutting down.
  • If you turn on the projector with the remote control, check the batteries.
  • Make sure all projector latches are closed.
  • Try resetting the lamp timer. Make sure the projector is not in standby mode.

Projector Lamp Is Burnt Out

Lamp life varies from projector to projector, but eventually, all lamps will need to be replaced, so this is one of the most common projector problems. Signs of a burned-out lamp are:

  • Check that the lamp is lit. If the lamp blinks red or orange, the lamp needs to be replaced.
  • If the projector powers on but there is no image, the lamp may be out.
  • If the projected image becomes discolored or blurry, the lamp may burn out quickly.


One of the two biggest signs that a projector lamp is deteriorating is when it dims or when the projection appears speckled.

The current must flow from the terminal through the filament, so you need a multimeter to detect if the current is reaching the opposite end.

A discontinuity or the current not reaching the other end is why the lamp is bad and needs to be replaced.

However, use the projector’s lamp hour meter before opening the projector.

The lamp hour meter will let you know when the lamp is nearing the end of its life and no further testing is required.


Can you test the projector lamp?

It is impossible to test projector lamps with common electrical testing equipment. To test projector lamps, you need to purchase special test equipment.

What happens if I don’t replace my projector lamp?

Over time, after hours of projector and lamp use, the colors will begin to fade. You may not notice any fading initially unless you are paying close attention to it. 

The only way to tell the difference is to do a direct comparison with another projector with a new lamp. If the lamp is not replaced, it will become dimmer over time.

How Many Years Does a Projector Lamp Last?

There is no standard lamp life. Most of the lamps are rated at 5000 hours, some are 6000, and some even 7000 hours. 

What Happens When a Projector Lamp Dies?

When a projector lamp dies, the light it emits is no longer visible. This can be a problem if the lamp is used to project images onto a screen, as the image will be completely dark. If the lamp is used for general illumination, it should still work fine.

How Long Do Projectors Take to Warm up?

It takes about 1 minute to warm up for the first time, and the lamp will take another 20 minutes to stabilize.

How do I know if I need a new projector bulb?

Brightness and luster begin to fade. The human eye can get used to faint images and may not notice the problem. Try increasing the color of your projector. If the image is still dark or unchanged, the bulb needs to be replaced.

Can the projector lamp be replaced with LED?

Light sources are manufactured based on projectors and are available in various quality levels. Some of the projector lamps can be replaced with LED lamps. 

However, this is not an easy task. LED bulbs are a new technology. 

If you replace the projector bulb with an LED bulb, you may need to redesign the heatsink, internal motherboard, or transformer for the best results.


If you can’t see any signs of trouble with the lamp, the projector is probably working fine. You should check your projector’s lamp for proper operation before the show.

Some people will even put an extension cord under the lamp to help with this task. Another way to test the lamp is to check if the lamp is burning.

A burned-out lamp will usually be black. If you have a burned-out lamp, you should replace it immediately. If you see something dark, that might mean that the lamp is bad. You should call the technician or repair man to come and fix the lamp.

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