HP 180C replaced the 180A (& I think the CRT div went up slightly, as well).
HP184A is a faster writing replacemnet for the 181A, still variable persistence w/fast write mode.
The 180 series of oscilloscopes work fine, but they are a bit large & heavy for what they do.
Plug-in capability is definitely a double-edged sword; I've learned to avoid connectors whenever I can.
The 1740A & 1741A 'scopes provides 100MHz capability in a smaller package with better triggering.
They've been selling quite cheaply on eBay (US).
Manuals should be available readily for any of these.
Regards,
Pete Rawson
