[tritwi]

Hi! The F 11 chassis is one of the most reliable made by Thomson. Since you saw it working month ago then you know the quality of the picture. Assuming that the picture tube was good then you might start to check around. The first thing I advice you to do is to check voltages that come out of the plug (BP03) mounted on the board on the upper side of the big transformer. You should measure a dc voltage of 90/100 V across pin 4 (+) and 3 (-). You should also have a dc voltage of 12 V across pin 5 (+) and 2 (-). There is another dc voltage of 12 or 24V (it depends upon the fact the tv is mono or stereo) across pin 1 (+) and pin 2 (-) of plug BP 07 but since this voltage is used to supply power to the sound stage then you may omit to check it.
Since you say you have a dead set with dead display I think the problem might be a lack of the mentioned 12V (the one you measure across pins 5 and 2 of BP 03). This voltage is brought to the main chassis through a (black?) single wire. If you have the correct voltage coming out at the BP 03 plug then check if the wire is corectly connected on the main chassis. If you have no 12V then check RP 43 (0,47 ohms) and DP 42 (bridge rect.). These components are mounted directly on the board directly soldered to the huge transformer. Not very easy to check...
Should you have the correct 12 V then have a close look at the battery mounted directly on the main chassis. It's not unusual a leakage of the battery and corroded printed side of the chassis and damage to the connections and microprocessor unit.
I think I gave you things enough to check for the moment. Please feel free to ask if you have further problems. I'll be more than happy if I can be of any help!
Have a nice time
Marco