keyboard almost dead

Hi,

I am new to Jornada. I was given a 720 model that is in very good
condition but its keyboard does not respond except for the power and
reset keys.

With googling a little I have found several mentions of dead 720
keyboards due to several problems. Unmounting the keyboard and unplug
the keyboard ribbon cable with some KF contact cleaner in the connector
did not fix the problem. The keyboard seems in good mechanic condition
(as the whole unit) I noticed no blocked key.

Could someone give me some advice ? Do you think that I need to replace
the keyboard ?
-- 
Sébastien Kirche