I got to Q4497, it is not being triggered by wither the normal trigger or the auto.

I found (IIRC) Q4498 to be bad I think. With it in the end of the sweep switch is pretty much grounded all the time, I changed it and now it has voltage.

Regular trig and auto, seems like two problems but as we all know it is likely just one. The only thing I can see dong it to both is the lack of detection of the end of the ramp out the switch.

But where is that then ?

I understand the Miller type ramp generator and I understand the switch changing the rate of charge, or I think in this case discharge. But somewhere the circle is not complete.

Anyone familiar with this circuit or similar ? I am not completely stumped (yet) but I do not want this to take a year.

On Thu, 8 Apr 2021 21:28:59 -0700 (PDT), "
wrote:

I got to Q4497, it is not being triggered by wither the normal trigger or the auto.

I found (IIRC) Q4498 to be bad I think. With it in the end of the sweep switch is pretty much grounded all the time, I changed it and now it has voltage.

Regular trig and auto, seems like two problems but as we all know it is likely just one. The only thing I can see dong it to both is the lack of detection of the end of the ramp out the switch.

But where is that then ?

I understand the Miller type ramp generator and I understand the switch changing the rate of charge, or I think in this case discharge. But somewhere the circle is not complete.

Anyone familiar with this circuit or similar ? I am not completely stumped (yet) but I do not want this to take a year.



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RL