Re: 7B71 time base jittering at 50ns/div, but not other speeds.


On Wed, Apr 17, 2019 at 04:56 PM, Jim Ford wrote:

I've been following this thread with some interest because I have a 7B71
myself.  Planning to try it in 7904 when I get a chance.
To Jim & John:

I just tried a 7B71/7B70 set in a 7904 (they were really meant for the 7704(A) but work fine in most any 7xxx mainframe).
I've always found the trigger setting knob in these time bases (7B5x and 7B7x) a bit finicky in more critical situations. Triggering on a < 1 ns edge at 20, 50 and 100 ns / div. with about 4 div. signal amplitude was no problem but it wasn't difficult to have some jitter by playing with the trigger level adjustment knob. It was slightly different for different speed settings. All to be expected. Difficulty in removing the jitter with a reasonable amplitude (> 1.5 div on screen for a reasonably fast signal) and reasonable steepness of the slope would indicate a time base problem, *unless* trying to trigger too close to the amplitude extremes.


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