I'm sorry to hear that you're having this issue.
I'd recommend having a technician take a look at the unit. This might help eliminate un-necessary parts/labor charges, and they'd likely be able to give a better diagnosis after looking at it.
I have a HL-P4663w DLP set , its about 5 years old , a couple weeks ago it lost video for no reason... I had audio but no video--So I changed the lamp--no luck still does it -I replaced the color wheel 2 years ago& I can hear it start spinning when I turn the set on
If I shut it off when this happens & turn it back on ,it'll work for about 20 minutes then go out again
I don't get any codes on the power button when this happens & when I lose picture the lamp stays on(I can see it burning from the back) so I don't think its the ballast---Its not the switch on the door to the lamp because that switch shuts the whole thing down
I don't want to change alot of things on this thing & have them not fix the problem--So I'm wondering if anybody has seen this problem & what can I do to fix it