Clean colour wheel of Optoma HD72

Here are my instructions for cleaning the colour wheel of the HD72 when colour flashing problems are observed (mine did this only after 6 years of faithful service).

Cover the lens with the supplied lens cover to keep it clean and safe during this procedure.

Turn the projector off, let it cool if required and remove any mounting brackets to allow us to take the unit apart. Turn the unit over and remove the single screw that keeps the lamp cover on...

Lift off the cover and you can see the lamp in place in the carrier. Take hold of the metal bar and firmly pull the bulb and carrier out of the projector. Place the bulb safely to one side, ensuring that you do not touch the bulb. This will leave a cavity in the unit.

Use a long philips screwdriver to remove the five screws that hold the top of the casing to the bottom. Unscrew them all fully and then carefully tip the unit over and let the screws fall out. Gather them up and put them safely to one side.

With the unit now resting on the feet, from the front of the projector, careful lift the front of the housing. The top is held on by clips and these can be popped out by sliding a flat blade screwdriver carefully down the seam and levering the case apart...

When all the clips have popped out, the lid should come free as shown below. Carefully raise the lid and you will see that there are two cables connecting the lid to the main unit (for the controls on top).

Reach in a carefully remove the cables to allow the sections to be separated. Lift the lid away and set it safely aside.

OK, that was probably the most stressful and hopefully your case has separated with no marks or damage (mine did quite easily). We can now look into the projector and start on the cleaning.

To gain access to the colour wheel we need to remove the cover to the left of the lens in the picture above. This is stuck down, but gentle pressure will cause it to come unstuck and be removed.

Lift it away and set it aside for later. This now provides access to the colour wheel. On my projector, dust could be clearly seen on the wheel itself but also (and more importantly) could be seen on the sensor of the colour wheel, see here as the small vertical circuit board just above the case pillar, in the photo below.

Using an air blast, carefully blow away the dust. Take care not to blow it into the optics of the unit (otherwise there will be more cleaning later !) and ensure you do not spray propellant by keeping the can vertical and bending the straw if necessary. Blow the dust off the colour wheel and from the sensor.

I found that angling the straw down into the area where the circuit board of the sensor  was most effective. This can be seen in the picture below on the right of the colour wheel assembly where the wires enter the part.

This should leave your sensor and colour wheel nice and clean.

Reverse the disassembly process by replacing the black cover over the colour wheel (the sticky should still hold it in position) and then put the case back together. Clips the halves together and then re-insert the 5 case screws. Plug the lamp back in and then replace the lamp cover. You may wish to test the projector at this point and if all seems well, then re-fit any mounting brackets and install back to your room.

Mine has been up and running now for many hours with no reoccurrence of the flashing colour problems, so it looks like this has been a very successful repair.

Thanks to all the posters on the internet that helped give me the confidence to try this at home, and I thought that I should give something back but posting these very specific colour wheel cleaning instructions, that might help someone else in the future.

Don't be too afraid of having a go at this job. It was a little stressful, but in the end turned out to be a lot easier than I thought. Good luck !