This is a short story about a modification I made to my Davis Projector. It now runs much quieter. As always, I accept no responsibility should you decide to try this yourself. It worked for me. It might work for you too.
The colour wheel in the Davis DL-450 is quite loud. This is due to the way the wheel is mounted to the chassis of the projector. In my unit it is fixed in position with some rather inflexible mounts. By upgrading the mount with softer rubber the idea is to reduce vibration from the wheel to the chassis.
The projector with the top cover removed. Notice the colour wheel located towards the rear of the projector.
A close-up shot of the colour wheel. Notice the way the colour wheel is fixed to a U-shaped piece of plastic. The U-shaped piece of plastic is then fixed to the chassis.
This is a photo of the exhaust fan. There are three fans in the Davis, two inlet fans and one exhaust fan. Notice that the exhaust fan is bolted directly to a piece of metal. Another mod to consider is the soft-mounting of this fan, however we will not deal with this today!
The exhaust fan with the grill removed.
Some tools you might need. I didn't bother to take note of the sizes. Call me a slacker. :-)
Once you have removed the facia panel from around the input sockets you are greeted with this view. The top row of sockets are on a removable board.
After removing the board.
An updated list of tools required. :-)
Unscrew the cage (the metal with all the holes in it) from the chassis and swing it out of the way. This is necessary in order to get access to the Allen key bolts holding the colour wheel in place.
A view of things once the cage has been moved out of the way. We now have space to work. Also notice the colour wheel has two electrical connections. The one coming out of the top of the wheel is grey and runs along the top of the cage. There is another connection coming out of the bottom of the wheel. This is a narrow brown flexible connector (visible in photo). This attaches to a PCB underneath the chassic. When you remove this make sure you can identify which way round it goes when you put it back as it's not keyed! Very close inspection of the connector will reveal the correct orientation however.
A shot of the socket where the grey connection from the colour wheel plugs in.
Here's a better shot of the wheel and the pesky brown ribbon cable. Unfasten the colour wheel using the Allen key.
Here is a photo of the wheel. Three coloured segments and a clear segment. Be careful with the wheel as it looks very delicate. It would probably be a Bad Thing (tm) to break it.
Turning the colour wheel over we see the U-mount that must be removed.
These three rubber grommets are what we're going to use to replace the standard solid rubber units. These grommets are super squishy. I found them in a Samsung DVD player, model 611 or something. They were used to provide suspension in the DVD player.
Grommets in relation to the colour wheel.
Colour wheel with the U-mount removed.
The U-mount has three metal standoffs press fitted. These are used for attaching the U-mount to the chassis. We are going to replace these metal units with the soft rubber grommets. Pull them off one by one using pliers. Be careful not to break the U-mount.
Pop the grommets into the holes created after removing the metal shandoffs. Excellent!
Some way to prevent the mounting screws from coming undone is required. One of the Locktite products would work well here, used on the thread of the mounting bolts. I didn't have any handy, so regular glue will hopefully work as well. Note that if the mounting bolts come loose, the colour wheel will drop out of position and hit whatever is nearby. This will happen at a few thousand RPM and it will probably shatter. This would be a Bad Thing (tm). Make sure your mounting system is reliable. Or use glue and hope for the best. :-)
This photo shows the colour wheel mounted with the new rubber grommets. Reassemble everything and try it out. I would suggest that you do not operate the projector with the cover removed. The bulb, which is visible with the cover off, emits ultra-violet which damages your vision. The unit will not be properly cooled without cover in place, and to top it all off, there are high voltages (25kV) on exposed places in the unit.
Before the modification the colour wheel could easily be heard. Changes in vertical refresh rate cause a change in colour wheel speed and at certain refresh rates the colour wheel created more noise than all the fans together. After making the modification it's difficult to hear the change in colour wheel speed when changing refresh rate. That's certainly a great improvement!
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