Dynamic Contrast Error on NEC Projectors: Causes and Solutions

Projector dynamic contrast error is like a stubborn pest.

You can’t shoo it away, and you can’t wish it away. Unless you tackle it head-on and exterminate it, it keeps persisting and multiplying.

While dynamic contrast error doesn’t cause further damage to your device, it won’t go away unless you find and solve its root cause.

And you won’t be able to use the projector in the meantime.

Fortunately, it’s easy to correct the dynamic contrast error on an NEC projector. Follow along as we show you how.

What Causes Dynamic Contrast Error on NEC Projectors?

Dynamic contrast error on NEC projectors usually occurs when there’s a problem with the dynamic iris.

The dynamic iris is a projector component that controls the amount of projected light, depending on how bright or dark the image is.

It’s found between the lens and lamp and works in an opening-and-closing motion. 

When an image is bright, the dynamic iris opens wide to allow more light to reflect the picture’s brightness.

And when the image is dark, the dynamic iris closes to minimize the amount of light projected onto the screen, thus preserving the image’s dimness.

It opens fully when the brightest white is cast and stays fully closed when the darkest black is projected.

In other words, the dynamic iris is responsible for bringing out the dynamic contrast in each scene.

The dynamic contrast error mostly occurs when the iris mechanism does not open or close properly.

How Do You Know Your Projector Has A Dynamic Contrast Error?

When the Dynamic Contrast feature is not working as it should, the status light turns red and blinks nine times. The blinking cycle continues in a 5-second on/off pattern. 

You may also hear a whirring noise as the status light is flashing.

When this happens, the projector will not turn on, not even when you press the power button.

The blinking cycle may play out a couple of times before the projector automatically shuts down. And when you attempt to power it on again, the status light repeats the nine-time flashing cycle.

How to Solve the Dynamic Contrast Error

Thankfully, when caused by a faulty dynamic iris, the dynamic contrast error is solvable. It may take a bit of effort, but with some guidance, you should be able to correct the error. 

You’ll need to open the projector for this process. We have to warn you that this method will void your warranty. 

If your projector is still under warranty, consider contacting NEC for help instead of tackling this yourself. It’ll take you longer to resolve the issue, but at least your warranty will remain intact.

Here are the steps to follow to correct the error:

1. Disconnect the power cable

Unplug the power cord as a safety precaution. 

Capacitors can hold electricity for a while after the power supply is disconnected. So wait at least 30 minutes for them to discharge before you open the projector.

2. Remove the air filter cover

Most NEC projectors have an air filter on the side or back. Locate the filter on your projector and remove it. 

3. Remove the bulb cover

Locate the bulb cover and remove it. 

It’s usually located on the top side of most NEC projectors and is easy to identify because it’s the only casing on the projector cover.

The bulb cover is held in place by a screw. Use a screwdriver to loosen the screw, then slide and lift the cover to remove it.

4. Unscrew the projector casing

The screws holding the case can be as many as 10. Loosen and remove them all. 

You can keep the screws in a container of some sort as you remove them, so you don’t lose any of them in the process.

Remember that screws come in different lengths and are not interchangeable. Replacing any screw that gets lost with a different type of screw could damage the projector. So be careful when handling them.

5. Lift the casing

Lift the casing slightly, not all the way up, and then look for a wire connecting the lens cover to the projector PCB board. 

This is the sensor wire for the lens cover, and you don’t want to break it by yanking the projector case off.

Pull the wire from the PCB to disconnect it. Then lift the case and put it aside. 

6. Remove the screws on the PCB

There are about three more screws securing the PCB. Unscrew these.

7. Disconnect the RGB LCD ribbons

Many projectors have three ribbons. Disconnect these carefully, taking caution not to break them.

You’ll need to pop out the black part to release the ribbon. Then slide the ribbon out. 

Remember, you’re only releasing the ribbons from the prongs holding them in place so you can lift the mainboard. So don’t pull out the ribbons.

8. Lift the PCB board

Disconnect the cables on the side (usually two) of the PCB board and the iris cable. 

The iris connector is the largest and has the highest number of cables. So you can’t miss it. But to be sure, confirm its location from your user manual.

Pull the PCB up and back to expose the interior part of the projector.

Make sure that the PCB rests on something so that you don’t strain the wires. You can use the projector casing to support the board.

9. Remove the heat shield

Locate the metal shield covering the iris and remove the screws securing it.

The shield is right next to the lamp.

10. Remove the iris mechanism

Unscrew the iris mechanism and remove it.

11. Remove the iris motor

The iris mechanism has a motor attached to it. Remove the motor.

Not sure how to identify it? It’s the cylindrical component with a small PCB on its side.

12. Remove the capstan of the gear mechanism

The gearing mechanism has a bracket on top of it. Loosen the screw holding it and remove the bracket.

Then remove the capstan.

13. Remove the iris blades

Now you’re down to the most significant part of this operation: the problematic component.

Begin by removing the plate holding the iris mechanism. Just loosen the screws and lift the iris unit.

Use a screwdriver to raise the metal blades and remove them.

Apply lubricant to the capstones left at the base of the mechanism. You can use a cotton swab  for this.

Do the same on the blades, and don’t forget the holes at the bottom where the capstones attach.

14. Reassemble the unit

Reassemble everything by doing Steps 1-13 in reverse.

15. Test the iris unit

Reconnect the projector to power and press the power button. 

If:

• the iris mechanism opens and closes smoothly
• the whirring noise is gone
• the status indicator lights up in a steady green color
• and the projector turns on as normal

You’ve solved the dynamic contrast error. 

This detailed video takes you through the process step by step.

If this does not solve the dynamic contrast error, your projector may need more specialized attention. Contact an NEC dealer near you for assistance.

Conclusion

For the most part, NEC projector dynamic contrast error is solvable. 

But it calls for you to open up the projector and access the interior components to do that.

Take apart the iris unit, lubricate it, and reassemble the device. 

If this does not solve the issue, consider contacting an NEC dealer for help.