Now that the 535A is pretty much done I was left with the dilemma as to where will the monster reside? I didn't want to leave it on the cart since that's specifically for the 7904 and the 7000 series plug-ins. And it had to be somewhere where it would be relatively easy to service without jack assing it around. Here's what I decided upon....
The 2465 DMS which previously occupied that corner has been moved. The 535A fits nicely. It's a good thing I built bench 2 strong.
A size perspective. It even makes the 7904 look small.
Discovered something interesting about the trigger in these older scopes that don't use a tunnel diode in their circuitry. And at first it didn't make sense until I RTFM. For repetitive signals below approx 5 MHz the preferred method is set the Triggering Mode to “Auto”. Set the Stability to “Preset”. In this mode the trigger is completely automatic and stable. The Triggering Level control has no effect, unlike more modern scopes. But the Trigger Slope, either + or – does work.
For signals above approx 5MHz set the Trigger Mode to either AC or DC and now the Stability and Triggering Level now come into play. Although with the CA plug-in in Alternate Mode this is the preferred trigger method regardless of the signal frequency. And again, it does work well.
The spare CA plug-in has been shipped. But it's coming from Oregon via USPS economy which means pony express cross country. Projected delivery not until this Wednesday.