How to change old (pre 92) Artemide Tizio Light bulb?

hi There

After a failed attempt to change the bulb I had found the correspondence to an old question "How can I fix my Artemide Tizio lamps? " logged in Oct 97.

I have changed to a new bulb, but it is not working and I am also getting little flashes when trying to check the current. (I admit I am pretty clueless with these things, still thought it should be possible to change a bulb :-))

The old message mentions that it might be best to just change the entire head (to the newer model). It also mentions that the transformer could have been damaged in the change process.
How can I find out whether my transformer has been damaged? (before I spent the money for a new head)

Many Thanks

regards
Alex