Joule Thief

[xee2]

Mk1

@xee

I would love if you posted it again.

For the flyback i will just map it first check the ohms , then try it , if it doesn't work i will reverse one of the leads , that should do.

Thanks again.

Mark

I posted circuit. If you need more info I have more.

[Yucca]

@xee

I would love if you posted it again.

For the flyback i will just map it first check the ohms , then try it , if it doesn't work i will reverse one of the leads , that should do.

Thanks again.

Mark

Hi MK1,
The difficult bit is finding the HV return pin. one tip is to use 6V supply (4 x AA) to hand pulse a coil that has approx 1ohm resistance. set up a small spark gap (1mm) between the red HV lead and a  croc clip flylead. pulse the coil and clip the flylead to various other pins looking for a small spark in your gap. this way you hunt for the HV return pin. look for the strongest spark. You may need to reverse the 6V on the 1ohm coil before you find it because of the integrated diode. once you find it you also know the polarity needed for the drive too. good luck.

[Mk1]

@yucca and xee

Thank guys !

Mark

[jeanna]

...They are either not used or are additional pickup coils that are used for some function in the TV set. The advantage of the flyback is that it has a very large number of turns with high voltage insulation for the main pickup coil. You could make the same thing on a toroid if you could get that many turns on the toroid.


EDIT: remember, the Fuji is not a toroid either, but it works like a toroid transformer.

Ah, I see.
thank you,
jeanna

[Yucca]

@mk1, forgot to mention, if you think you find the HV return then also check it for isolation from all other pins, if it's standalone then its definitely it. when mapping it just make sure you use a low current source of no more than 6V but more than 4V.

@all
be careful with these at higher drive levels or even at lower drive levels if you start charging HV caps. Left hand in the pocket when working on this stuff is always a good habit to get into even if it is a bit annoying.