I had the same problem and have managed to repair it myself. In my case the bulbs behind the screen that illuminate it weren't coming on, removal of the cover will allow sunlight in and you will see the display working, or a torch if light is poor. The two metal pins going inside the unit from the bulbs fit into a connector on the circuit board, this connector will probably have a dry joint (solder parted from circuit board). When you push on the display you are distorting the unit and making the solder touch again, it soon parts again though and the display goes blank again, I had 4 x 10p coins taped together and wedged in a corner for about a year until it got worse. Remove the unit, two torx screws and the connector is all, open it up gently with a knife to ease out the plastic cover away from the clips and a screwdriver to ease it open, gently sperate the top from the bottom, the connector in question will probably come away with it, mine did, pay attention to where it came from and with a fine soldering iron you can resolder it back into place, it has 4 solder points but one was inaccessible, but it worked fine with 3, it has been perfect since.
Yep, new unit my arse, they dont care as its not their money, even if they did it for you it would only be an hours labour.
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Good Luck
Ron
Ron, July 2006