From an internal HP document Bench Briefs 3rd and
4th quarters 1990
1826-1388 makers code 03794 AM7960
Thanks for that! My equivalents list (also ex Bench Briefs, it's the same
one that's on a website somewhere) is too old to contain it :-(
Looks like I made a good guess then :-). And since I've been pointed at
the data sheet, I can get on with figuring out this PCB...
-tony