external trigger for oscilloscope

[pccmd]

I have an old analog oscilloscope(Tek 7633) and wish to build a tunable external trigger of sufficient quality.
Any suggestions as to circuit design?

 

[amdNRA]

This Tektronix scope should have no problem when using external trigger to syncronize a signal and lock it. What problems are you having? I doubt one can throw together a somewhat simple circuit that surpasses what Tek has done.
Later, Gil.

 

[pccmd]

ext. trigger 555

Gil,

I was trying to trigger with 555->inverter creating spikes of same frequency as sine wave from twin-tee oscillator....but triggering poorly received.

I did use osc. probe(second one) to input the above trigger signal to my Tek.