Actually there are two different manuals for the 465B. The early 465B were actually "engineering models" pretty much made by hand (the better of the two types many believe) and followed by the "production 465B.
If I'm not mistaken , one of the great things about the early 465B was that the xistors "plugged in" to the circuits using neoprene sockets while the later production models had them soldered in to the circuits with the 'plugables" being obviously much easier to troubleshoot
One manual covers S/N B059999 and down with other covering S/N B060000 and up. I have CD of both,
There are some significant differences between the two so unless you have the right manual many things don't match...
I repaired/ refurbished all 400 series scopes for quite a while. Must say that of all of them my favorite far and away is the 465B.. a really GREAT scope....well worth putting in top shape .... On your trigger problem.... there are tunnel diodes used in the heart of the trigger ckt... they are "weird " little devices that have unique electrical characteristics that are perfect for use in a trigger ckt... could be your problem... just a guess
