On 4/13/19 3:59 PM, Albert Otten wrote:
Step 19 requires that the A time base can be triggered from both 7A plugins at one and the same trigger level. As you noted that was problematic and you chose to set the level correct for the left 7A; hence the right 7A won't trigger the time base; the sweeps stop unless you set AUTO.
Likely you use DC triggering. And you positioned the traces in the upper half and in the lower half, so at quite different DC levels and hence trigger output levels. What happens when you move one trace up or down, or when set the time base for AC triggering?
Instead of trying AC, I tried another scope and it works fine, and the lights say right vert A, and left vert A when in ALT and ALT. That gives tow traces with different time bases. Here's a photo:https://www.cibolo.com/forsale/Tek-7904A-ALT-ALT-14.jpg