After quite a bit of work with the front panel (see earlier post, massive transport damage), and repair of its most beautiful and complicated inner workings, the remaining item to be fixed: the main output connector (N-type connector). The original one, damaged beyond repair, and the bracket holding it, severely bent, and a broken-off screw stuck in it.
Screening through my parts stock, found a rather old but still good panelmount N connector. It has a slightly different inner construction (the original 8645A has a quite long gold-plated coaxial air-line in the connector; replacement connector has no gold plating), but within reason, this should not matter.
The bracket and assembly was fixed back home, in good old Germany, in the mechanical workshop, during xmas vaccation.
Now, looking at the result, quite pleased with the outcome of quite a few hours of work (and some expenses, for a replacement HP System 2 front panel frame, see earlier post):
Note that there are two handles now mounted to the unit, not so much for carrying it around (about 70 pounds!), but to protect the front panel.