3 horn vac TSG update

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Original poster: "jpeakall by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jpeakall-at-mcn-dot-org>

Howdy All,

Finally got over a nasty infection and got back to work on my triggered 3
horn sucker gap. The story so far:

I am using Terry's controller circuit, without the Carcom filter and
associated MOVs. I do have the three MOVs around the dimmer and IC. I don't
have any power resistors on hand, and so far have had no luck using various
lights and so on as loads. So I don't have the range that I should, but at
least can experiment with firing the gap. Any suggestions as to homebrew
loads would be great, I'm going to order some PRs from Digikey on Monday,
but would like to play with it between now and when they arrive.

I went and got an Accel IC out of my Mustang, and was using it with 3x700pf
caps in series, and was surprised to see that all I was getting was around
29kv, about what I get out of a standard IC. As with regular coils, I found
in necessary to dunk the whole assembly into oil to prevent arc over and
loss.  Anyway, hooked it all up, was running fine, then there was a pause in
the firing of the gap, and piff, both the dimmer and the Accel IC were shot,
the IC with an open in the secondary. Resonant rise with the caps maybe? I
wonder if safety gaps on the IC circuit might be a good idea. Anyway, I took
out one of the caps, and replaced the IC with a regular one. Surprisingly,
once I dunked it into oil, I am getting about 34kv out of it, better than
the Accel coil.

The new system has about 20 min on it so far, and is doing fine. My previous
blowing of dimmers was doubtless due to the 15uf/1.5 uf typo. One thing I
find is there is sometimes a slight delay when I kill the power to the
trigger, and the arc continues for a fraction of a second. Caps in the
trigger discharging? Another odd behavior, and one I have noted using a
dimmer/IC setup to run small TCs, is that occasionaly the trigger arc stops,
and to restart it I have to move the dimmer knob slightly or turn the power
on/off. As long as I leave it in place the trigger won't fire.

Is there any way without a scope to determine the pulses per second of the
trigger? I tried with a frequency meter (archaic, of questionable quality)
with an HV probe, and got nothing but garbage.

Jonathan Peakall