Thanks all! With the help of a friend who:
a) Is younger and has better eysight
b) Is in possession of better desoldering gear
c) Has more exeperience
We replaced both comparators (ch 8 and ch 1 broken). We noticed that the solderability of the chips was so-so, possibly because they were manufactured some 20 years ago. Wonder if there is a good procedure to restore solderability of old chips?
Anyway. These links ars good:
The latter has a post with ppin descriptions that should help with troubleshooting.
Anders