I've searched everywhere, but can't find how to get into the service menu of my GT50 so I can check how many hours it has run.
I did find this below on HDTVtest.co.uk but it does not get me to the service menu.
Thanks in advance for the help.
Disclaimer: By entering and adjusting the service menu, you risk voiding your warranty and damaging your TV. The instructions below are specific to the British GT50 model, and should serve as a guidance only... I take no responsibility for your actions and outcome.
Input signal = whichever source you wish to calibrate, for example Sony PS3 into HDMI 1. Engage [THX Cinema] mode, display the test pattern(s) on screen, then while holding the volume button on the TV, and press 0 three times on your remote which will bring up the service menu.
Press 1 on your remote twice, which will bring you to the [WB-ADJ] submenu.
Once you're there, press 9 twice on your remote to change the picture mode to [Cinema]. This in conjunction with [Colour Temp] "Warm" allows you to calibrate greyscale in [THX Cinema] mode.
Press  to cycle through the RGB cuts and drives. I suggest only adjusting [R-CUT], [B-CUT], [R-DRV] or [B-DRV].
Write down all the values before you change them.
Use the volume up and down buttons on your remote to change the values.
Once you're happy with the measured greyscale, press [OK] on your remote to commit and save.
The [Exit] button will get you out of the service menu. Remeasure outside service menu, as it may be slightly different due to different brightness etc. If necessary go back to the service menu and adjust again.