Further information the following part of the problems:
3) Some sort of problem with the Z and Y axis controls.
b) When operating in Alt mode potions of the waveform are absent
(though they sometimes re-appear for a few moments) and the
delaying sweep is distorted somewhat.
Test condition is with the 7B92 set with both sweeps set to 1mS per division, a 1kHz input signal, and ALT mode active.
Looking at U380 pin 3, I see (NOT)SWEEP_GATE +ve going pulses from about +2V to about +6V at about every 12mS.
I think I should see pins 5 and 6 alternating between 0V and about 6V with the changeover at every pulse on pin 3.
What I actually see on (say) pin 5 is an approximate square wave (so far, so good), but the changeover is every 1mS, rather than every 12mS or so.
If I change the input signal to 100Hz, the changeover is now every 10mS, and to add oddness on top of oddness, the (NOT)SWEEP_GATE signal on pin 3 is now a square wave with a switchover every 10mS!!!
Dave
