Chip,
Some thoughts and ideas:
You can hold a fluorescent bulb near the VTTC to see if it lights up. If it lights then the VTTC is oscillating so tuning might be the problem. Also if you look at the sharp breakout point in the dark, you might see a slight 1/4" brush discharge from the breakout point. This would suggest a tuning problem. I'm assumingyou have a breakout point attached which extends about 3" above the toroid.
Even though you built the project according to the schematic, just a minor differencein the diameter of the primary or secondary, or the thickness of the insulation onthe wire will affect the tuning. It's common for VTTC's to give no spark when first built. Tuning is usually the problem.
You could try reversing the leads to the grid coil also, it might be out of phase. That would stopthe whole thing from working. The feedback would be out of phase and the circuit would notoscillate.
Yes VTTC's will still give a spark at a lower voltage but the tuning will be different. When tuned for low voltage then the spark length will not tend to increase as you increase the input voltage. When tuned for longest sparks at high input voltage, then the coil might not spark until the voltage gets high enough. For example maybe 70 volts input will be needed to get the spark to break out. The sharper the breakout point, the easier the spark will form.
If the 833A is showing a red plate color that can be a clue too. If the plate gets very red but you have no spark output, that can mean the circuit is not oscillating (if I remember correctly).
Also if the RF bypass capacitor is defective that will tend to stop the coil from working also.
Your construction looks very nice. You may want to verify that the level shifter (doubler) diodeis wired in the correct direction also. But I guess you did that already.
John
-----Original Message-----
From: Tristan and Kayden gaming <maxford1980@xxxxxxxxx>
To: tesla@xxxxxxxxxx <tesla@xxxxxxxxxx>
Sent: Mon, Nov 23, 2020 7:34 pm
Subject: [TCML] New VTTC no spark
I built a VTTC over the past couple months. I am in no way an electronics
wizard. This will become more evidence I proceed. I used Steve Wards Single
A833 tube diagram. I have checked and triple checked all on the wiring. It
all seems correct. I can not get a spark out of it. Mind you, I live in an
apartment and I am trying to power it on a 15amp breaker. It will trip the
breaker at about 120 volts on the meter. I have set a CFL bulb on the
toroid while I do it, I never get a flicker. I bought the Doorknob caps
from eBay and haven’t really been able to determine if any of them are bad.
They are not shorted. I have tried (2) different A833 tubes. Same results.
I guess my first question is, will there be any discharge from the coil at
lower voltages or does the tube have to start before I get anything from
the output. I may just need to take it somewhere that I have more power
available. Thanks in advance for any help.
Chip Ford
https://drive.google.com/drive/folders/1-0_wMEyelu__OXy87W0I6wz9VlX6m6OF
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