Hi Barry,
A month ago this was the "complaint" in your starting message of this topic:
If a any of my time bases are set to display a highlighted trace, the trace is
very much too bright. If I'm understanding this function correctly, the
plugins are setting a voltage on the AUX Z AXIS line. If this were one or two
plugins, I'd suspect the signal being set on AUX Z-AXIS being incorrect, but
since this is occurring on all of them, I suspect something is misadjusted in
the CRT circuit of the 7704A.
I suppose you used a dual time base like 7B53A in the A slot, though my same remarks hold just as well for the 8B55/7B80 combo.
In both 7704As I tested with 7B53A the brightness contrast is *extremely* influenced by the A INTEN setting. With A INTEN at maximum there is hardly a visible contrast. But with just a slight amount below maximum the unintensified portion vanishes. It's difficult to find a compromise. With 7B85/7B80 this goes somewhat better.
In the fully CW position the wiper of the INTEN pot should make contact with -15V. The pot is very well accessible if you remove the upper-right cabinet panel. Maybe you have to exercise the pot a few times.
In my 7B53A the active intensifying voltage at TP620 is about -0.95 V.
[BTW Here is the simplified reason why A INTEN is so important for the contrast, in stead of INTENSITY. In the Z-axis logic IC U2587<3> the effects of A INTEN and Aux Z-axis are summed. The result (sink current) goes as Z-axis Signal to the Z-axis board<14>. There the INTENSITY setting determines which fraction of the Z-axis Signal passes via Q4175 (and really sets the CRT intensity) and which remaining fraction passes via Q4163 (and gets lost). So INTENSITY effect is not additive there to the A INTEN component but multiplicative to both components].
