Hi Andy,
Here some more details. Maybe you feel unsure about waveform voltage levels.
In Normal sweep mode, TP365 (the TD) is high (570 mV, my 7B92) during the sweep and low (65 mV) between sweeps (hold-off time and while waiting for the next trigger event).
In Intensified mode and Level pushed in, TP365 remains low during the delay period and then switches to high. For some reason the level between sweeps is somewhat lower now, 40 mV. The switch to high moves when the Delay dial is turned. (Test 'scope, at which the waveforms are shown, triggered for a stable saw tooth at TP408.) With Level out, the waveform remains the same, but you might see a small upwards shift in the high level where the delayed sweep starts.
Now if your TP365 goes high immediately (at start of the sweep at TP408), regardless dial setting, then check also one step backwards. You should see square wave signals at both sides of the diode pair CR358/CR359, while the duty cycles vary when you turn the Delay dial. If so, this confirms that the comparator Q359A/B is working. Next the collector of Q376 should switch to high after the delay period, with voltage step even larger than that of the TD.
If TP365 gets higher than about .6 V then the TD is defective.
Hope this helps.
Albert
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I had a few minutes to do some probing, and it looks like CR364 is being triggered on the leading (falling) edge of the square wave from the collector of Q376 which is fed by the comparator (Q359). R364 has an effect, but doesn't change the situation significantly.
The other possible issue I found was that CR940, and CR950 aren't affected at all by adjusting the delayed trigger level control, or even when switching it to external delayed trigger source (with no external input).
Thanks,
Andy
