Zenith M52W56LCD picture is turning green.

We have also had this problem before, you need to replace the color wheel. It is fairly simple to replace, just buy one and place it where the old one was.

sounds like bad light engine.

Go to the Zenith web site. If you have not adjusted any of the default settings for color, brightness etc then a possibility is that your light engine is failing. Just this month a Class action settlement was put in place that entitles owners of this and several other models to have the light engine replaced in home under an extended warranty until July 2010. You should be able to find a toll free number if you follow the link to Class Action Settlement. I did and a service tech is coming to my house next week to replace it at no cost to me. I looked and the parts alone are approx 600 to 1500 bucks. Good Luck!!

Go to the Zenith web site and find the link for Class Action lawsuit. LG/Zenith will pay for in home replacement of the light engine which may be your problem. There is an 800 number on the site to call.

YOUR LIGHT ENGINE HAS TO BE REPLACED ,MAJOR JOB !!

I turned off the internal speakers in the TV and the external speakers then worked.

For a really good step by step with pictures guide to replace it go to
http://www.fixyourdlp.com/blog/?p=34

For a good place to purchase the lamp go to http://www.discount-merchant.com/Original-Zenith-Projection-LCD-TV-Replacement-Lamp-p
/zenith_m52w56lcd_lamp.htm

I have found they have the best price on these replacement lamps. You might also check Ebay.

Good luck!

to me sounds like ballast or power supply

It could be as simple as dust contamination in the LE or lcd chip. You need a clean room to work on this area of the unit and NOTHING you can do there would make that possible, short of spending a few thousand to build one. Before we added a clean room enviroment we simply pulled the LE and sent it in to PTS - who has one and reinstalled...
In your case take it to a qualified shop and you'll save yourself a lot of grief..
Bill

need to take the unit to or have a repairman visit for a proper diagnosis. causes for shutdown can be many.