Acme Fixer's highly efficient Joule Thief help needed.

[TinselKoala]

All I know is that it is hooked up on the anode and cathode of the LED and that 400khz is what I am getting to it.

For those who may have missed the image.

Did you wind the toroid?

Well, that certainly looks like a JT waveform. What's the timebase setting? What happens when you bring a strong magnet over to the toroid?

[Legalizeshemp420]

Frequency changes.

The toroid I did not wind but performs exceptionally well in my standard JT so I am using it for this purpose but 400khz?

Timebase setting is .5us (lowest this 20mhz scope will go) and I counted about .5 for a full wave which is .25us for the period.

[TinselKoala]

Silly me, I put two layers of #27 on my little 3/8 inch toroid from a CFL before I measured it. It was 1.5 milliHenry! Now I've stripped off all but 14 turns (each winding) and it still measures 500 microHenry.

How many turns on the toroid?

[Legalizeshemp420]

18 on each side of 20 or 22ga wire or possibly 24ga but no smaller wire.

I can't measure the inductance value of it myself though.

[TinselKoala]

Frequency changes.

The toroid I did not wind but performs exceptionally well in my standard JT so I am using it for this purpose but 400khz?

Timebase setting is .5us (lowest this 20mhz scope will go) and I counted about .5 for a full wave which is .25us for the period.

There are 9 minor divisions across the shot you show. That makes 9 x 0.0000005 sec = 0.0000045 sec or 4.5 microseconds for the full screen. There are 17 full periods shown. 17/0.0000045 = 3.78 MegaHz. 

It's easy to misplace decimal points, for sure, I do it all the time, and maybe I did again. But whenever possible on an analog scope, use as many screen divisions and peaks as possible to do your frequency calculations. Accuracy improves with more cycles and more divisions.