Mitsubishi is VERY aware of the problem, and the WILL fix it if you are persistent. First a description of the problem - Many of the DLP chips that were manufactured 3-4 years ago are failing (a product defect). Basically, the DLP chip is a computer chip that contains a couple million tiny mirrors on it that move between open and closed positions to reflect white, black, or any color in beteeen onto your screen. The white and black spots on your screen means that the mirrors have stuck in the fully open or closed position. Once the mirrors start sticking, they will ALL eventually stick due to a product defect. They are supposed to work longer than 3-4 years. The newer chips, and the replacements chips, supposedly don't have this problem and should last longer. The remedy is to replace the DLP chip, or replace the whole circuit board (called a "light engine") that the DLP is plugged into. The DLP chip is a couple hundred bucks, while the whole light engine is more like $600 -- HOWEVER, you will not have to pay for this if you take the following steps:
1) Call Mitsibishi Consumer Relations: 1-800-332-2119
2) Explain that your TV has one of the "defective" DLP chip, be polite, yet assertive. You'll need to provide your model number, serial number, and proof of purchase (you'll have to fax the receipt of purchase...if you don't have it you'll need to call the vendor you purchased it from to get a copy).
3) Explain to Consumer Relations that you participate in numerous online forums, and you are aware of a possible class action lawsuit due to these "defective DLP chips". You would like to resolve this now, rather than participating in a class action. Let them know that you are aware that Mitsubishi has been good about replacing these chips for other people - even though the units are out of warranty, this is widely known to be a "product defect". If the consumer relations representative is not helpful (they should be very helpful at this point), then ask to speak to the director of the department (I didn't have to do this). The representative will create a "Case ID #" for you. Write it down.
4) Consumer Relations has procedures you must follow -- they will require you to contact one of their authorized repair technicians to come diagnose your TV and send in a problem report. Yes, the technician must come out (or you take the TV to him) even though you already know what the problem is. There were two authorized repair technicians in my area, I chose the one with the lowest trip charge. You'll have to pay for the initial trip charge yourself. Just do it (you'll get reimbursed later). The technician will come out, turn on your TV, & take a photo of it, record theserial number, then he'll send his repair estimate to Mitsubishi. Make sure he knows your Case ID and includes it on the report. He should send the estimate to Mitsubishi the same day. You'll call Mitsubishi 1-2 days later to confirm they received everything and discuss next steps.
4) When Mitsubish receives the estimate confirming that it is indeed the DLP chip (we already knew that), they will then "send it to review" to approve the cost of the repair. I was told to call back a few days later, but it took them nearly 2 weeks to cycle through the approval process. Again, be persitent but polite.
5) Once approved, you'll receive a call back from someone who will likely offer to pay for the cost of the part only. This is only their initial offer, so be prepared to negotiate! Explain to him that you are aware (through the online forums) that Mitsubishi regularly pays for some or all of the repair cost. The person I was dealing with immediately offered to also pay for 1/2 of all the other expenses. In my case, the labor ($300), initial trip charge ($50), and tax ($90), meant I was out just $214. I accepted this offer because I thought it was fair, although I expect they may have paid 100% if I was persistent (I saw another online post for whom they paid 100%).
6) Once approved, they will notify your technician, who will order the part, get it in 3-5 days, then come install it. Installation took only 30-45 minutes. If your technician's original quote is more than $200-$300 labor, he is quoting way too much for a 30-45 minute job, call him on it and get him to lower his price ($250 is the customary amount from what I've seen).
The whole process from initial contact to repair completion took 3-4 weeks. I now have a TV that looks like new, and I am very pleased. Much better than having to buy a new TV. I hope this help you. Good luck!