Overheating indicator and involuntary shu...

Magnavox 50" DLP 18 months old
At 14 months it ate the bulb (200 bucks later) Osram replacement bulb from Deadlamp.com. Now 4 months later the overheating light comes on and shuts the tv down. 6 times in 3 days. After it cools down it will allow you to turn it back on. I paid 1500 for this set and all the manual says is call a repairman. When the bulb went bad I called the local authorized repairman who wanted 100 bucks to come out and 75 an hour and said a new bulb would be 300 bucks on top of the service call. So, I cannot afford a repairman. I am very handy though if told how to troubleshoot and repair.