Pl check the boards below the CRT
There will be 4 boards.
The the 3rd will have a LED permanantely lit
The LED on the 4th will be blinking.
If both does not occur then there might be problem in any one of these cards.
The flat band cables from the key board goes to the 4th card.
Are the other keys working?
If you want to go to privilage mode then you have to press F3 and the PARAM softkey
SHEKAR