AAARRGGGHH ! My Tek TDS2012 display isn't working

I turned on my scope last night, and the display did not show the typical dark blue screen with language selection that comes up on powerup. This scope has a colour LCD screen, not a CRT. The screen colour is now a grayish/light blue, and stays that way for hours after I turn it on. The scope appears to be working though. I can push the help button and a front panel LED will activate, pushing default setup makes the LED go off. So internally, I think it's OK, it seems to be a display only problem. No improvement when I connected a probe to cal check terminal.

Some history. I work in my basement, and I haven't turned my scope on in a few months at least. I had a display problem once before, so I ran a hair dryer over its grill to heat everything up, problem solved ! I tried the hair dryer trick again, no go. I moved the scope upstairs and left it on for a few hours, no change, still the gray/bluish colour. I think the temp/humidity of my basement is causing my woes.

I am freaking right now, does anyone have any advice/similar experience on this series of scopes. Please make some suggestions before I have to cave in and take it to a service shop.

Much thanks,
gizzmo

I downloaded the service manual which had a good troubleshooting flowchart. The main board was bad, $450US to get a replacement module from Tek. This scope is simple to repair, everything is modular. Power supply is discrete components, the rest is surface mount. Very pricy to get boards, but a very nice scope to use.