Progress and more issues have shown up.
Replacement of the 8K/3W resistor in the Type 3A3 Vertical Plug-in fixed the no trace issue. Now have full control of a base line trace both vertically and horizontally.
The Type 2B67 Time Base refuses to have trigger lock. Comes close but then drifts. Extremely touchy adjustment of the Stability and Trigger Level. In order to troubleshoot this I may have to build up an extension cable so the plug-in can be operated outside the scope to gain access to the component side. But I'm going to hold off until the Type 3A6 plug-in is repaired in case there is a compatibility issue with this Type 3A3.
Other issues:
The Calibrator is totally dead. I suspect it might have gotten fried when there was the fireworks. That's low priority right now.
Bigger concern is the CRT. It's not as bright as it should be and it is displaying what is called “double peaking”. As you turn up the intensity it gets brighter, then darker, then brighter. That is a sure sign of a worn out CRT with many hours on it. I will be checking the CRT bias and HV but I doubt that's the problem. The CRT is near end of life but right now still usable with a sharp, if someone dull, trace.