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Old 16th Mar 2020, 8:13 pm   #4
Radio Wrangler
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Join Date: Mar 2012
Location: Fife, Scotland, UK.
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Default Re: Tektronix 465 not sweeping

Spot at the left edge of the screen is just what the timebase sweep generator should be doing while it waits for a trigger.

'Norm' trigger will leave it waiting forever if no trigger event comes along. With auto trigger selected, there is a timer that initiates a trigger and a sweep after some time has gone by since the last sweep. There is a switch and capacitor group on the timebase A (main timebase) switch to set a delay suitable for the timebase speed.

Select 'norm' and have a play with the trigger controls, turning the trigger level knob up and down to see if you can trigger a sweep. If you can't get sweeps this way, and can't get auto sweeps, then you need to find where the two paths converge and follow it into the sweep generator itself. Something has to act as a flip-flop to hold the I am sweeping/I am not sweeping state.

David
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