Re: Is this flyback suitable?
..., Thu Apr 05 2007, 04:24PM

The flyback itself should work just fine, and that at black wire coming out is the HV pin.

However, using it on the board it is on now might be hard (just try to power the board up like you would if the tv still worked, and hope for the best).

If that doesn't work you will have to make your own driver, which isn't all that hard. I even have kits available at the bottom of my sale/thread thread

Re: Is this flyback suitable?
Zum Beispiel, Thu Apr 05 2007, 04:27PM

You can (and probably want to) wind your own primary winding on the exposed part of the core. Around 5-15 turns would probably be good for 12V input, depending on the amount of power you want to push through it.

Then you just wire up the driver and see which pin the HV output wire arcs to.

Re: Is this flyback suitable?
Sparkie, Thu Apr 05 2007, 05:19PM

Thanks for the replies. So I can leave the original primary and feedback windings, and wind my own on the opposite side of the square core? Ill look into it!

The core does have a join in it with a metal clip will this affect my windings?

Re: Is this flyback suitable?
..., Thu Apr 05 2007, 06:50PM

You do not need to worry about the clamp on the core, just wind over it.

If you are using your own driver, then just leave the other windings in place. If you have trouble with arking between them you can cut them off, and then put some silicone/wax/anything besides hot glue over them.

Re: Is this flyback suitable?
Ken M., Fri Apr 06 2007, 12:03AM

I'd imagine its a DC Flyback, Had 1 that looked identical

Re: Is this flyback suitable?
Electroholic, Fri Apr 06 2007, 12:24AM

it s a dc flyback. I have a few of them, form old appleII monitors.

Re: Is this flyback suitable?
ragnar, Fri Apr 06 2007, 01:33AM

Actually, I would recommend making your windings inside the clip, then putting it back on -- everything will hold together just fine.

As for how to remove it from the board -- unless you're really handy with a soldering iron and a solder sucker, because this is an old phenolic circuit board (as opposed to fibreglass/epoxy), you can use some sidecutters to fracture the board around the flyback without damaging the blades.

If you clip between each pin, you can desolder, remove one chip of board, desolder, remove another, etc, until you're left with just the flyback

Re: Is this flyback suitable?
Ken M., Fri Apr 06 2007, 01:53AM

Id say just desolder it, they aren't too hard to do, if all else fails just beat it off the board, besides its not like you'll be using the board again after the flybacks offs

Re: Is this flyback suitable?
Part Scavenger, Fri Apr 06 2007, 02:39AM

Or, get a light torch, heat up the solder and *carefully* bang it solder side down on the table. Once you get the hang of it, flybacks will usually just lift out, provided they're not glued/screwed in. All the other methods work fine too, just don't break the ferrite.

Re: Is this flyback suitable?
Myke, Fri Apr 06 2007, 02:11PM

but won't you get lead compounds in the air?

Re: Is this flyback suitable?
Sparkie, Fri Apr 06 2007, 03:08PM

Cheers, it came out easy with a solder sucker. I will try to build the driver today and see what happens with it!

Re: Is this flyback suitable?
Sparkie, Fri Apr 06 2007, 06:43PM

OK, heres what happened. I wired it all up, and nothing. Changed the primary wired round the other way, and it makes a high pitch whine, but no arc. Although there is some high voltage on the output, enough to light a neon with just one wire attached :)

Heres a pic, im not sure where to go from here. Maybe build a better driver circuit. (Currently using the 2N3055) and maybe a better flyback?

Re: Is this flyback suitable?
Ken M., Fri Apr 06 2007, 07:40PM

If the coil whines, it usually means the coil has shorted out, at least in my experience, secondly it looks like ur using the the flybacks internal windings if you are DOn't those use 120v to produces the HV out, instead take some wire you have laying around and wind it around the exposed core where the clip is, 3rd I imagine you've tried it but try measuring from the HV out put wire to any of the other pins, with power off of course, just so you get an idea of how the and where and what the terminals are connect to.

Re: Is this flyback suitable?
Dr. Dark Current, Fri Apr 06 2007, 08:07PM

hi, try a better driver, do a search for "zvs flyback driver", you will need to wind your own primary of 5+5 turns. If after building this driver, you get no HV then for sure your fllyback is toasted.

Re: Is this flyback suitable?
uzzors2k, Fri Apr 06 2007, 09:04PM

The flyback should be fine, but fix your driver. I used the exact same driver setup as you for my first flyback driver, internal windings and all. Powered off a 9V battery it gave pathetic 3kV sparks. I went directly to the 555 driver from there, which was a great improvement. However if you want quick results wind your own primary and feedback windings. Try 3 turns for the feeedback winding and 5 turns for the primary. If it fails to oscillate reverse the windings until it works. The ZVS driver is also easy and fun. Try the 555 driver for high voltage low current sparks or the ZVS for flaming high current lower voltage arcs.

Re: Is this flyback suitable?
Tonic, Fri Apr 06 2007, 10:30PM


Could you give a scheme of this 555 driver?

Re: Is this flyback suitable?
Firnagzen, Sat Apr 07 2007, 06:30AM

Ummm. I would imagine he refers to the generic 555 driving a MOSFET circuit.

Sparkie, before you do anything else, I have a reccomendation. Don't use a 2n3055, those are pathetic for DC flybacks, no idea why. Use another transistor- the 2N3773 works ok, the KJE13009, very well.

Re: Is this flyback suitable?
uzzors2k, Sat Apr 07 2007, 07:05AM

For sure. I haven't updated anything for a while, and I have many other flyback drivers. I made this one recently, and it gives good sparks and arcs, tested up to 50V.

Re: Is this flyback suitable?
Sparkie, Sat Apr 07 2007, 01:50PM

Thanks everyone!! I did what whitearc said, and made my own windings, and it works! I put a little video on here. Thanks a lot to everyone here! Now im building it all into a neat box, 12v in HV out :) Ill post more once its all finished.

Video > http://www.youtube.com/watch?v=JOTn7A4BFfs

Re: Is this flyback suitable?
Dr. Dark Current, Sat Apr 07 2007, 02:31PM

you can connect the mosfet's gate directly to the pin 3 of the 555, the 555 has enough power to drive even a powerful mosfet's gate up to hundreds khz (tested with osciloscope)

Re: Is this flyback suitable?
uzzors2k, Sat Apr 07 2007, 03:18PM

True, but the transistors can save the NE555 in the inevitable event of failure.

Re: Is this flyback suitable?
Electroholic, Sat Apr 07 2007, 04:13PM

the totem pole was used to increase pk-pk voltage on the gate drive signal, mainly to lower the "low" voltage to turn the fet off completely. It will increase efficiency, so less heating on the fets.

btw sparky, windings look a little bit thin?

Re: Is this flyback suitable?
..., Sat Apr 07 2007, 08:54PM

Those windings are a little thin, but if you aren't running very much power it should be ok...

Also, you should attach a wire from the pin you were drawing arks from to the ground of the driver circuit, otherwise the secondary is floating and can stress the insulation on the flyback. Not to mention that it is less dangerous...

Re: Is this flyback suitable?
hydrogen, Sat Apr 07 2007, 09:08PM

hi, i'm new in HV stuff also, and not wanting to open nearly identical tread, i'll post my questions and problems here.
So i have similar (sort of) flyback from crt monitor, pic:

and a 555 circuit from:
HERE

I assume the other 3 leads protruding from (2 from the top and 1 from the bottom) are not necessary and can be ignored.

QUESTION 1:
where the arcing should occur? Don't I need the second lead of the secondary winding? The page says that arcing should happen between big fat wire witch had a suction cup on it and +12 terminal of my power supply (computer's PSU).

So I hook up the output form 555 circuit to the one of primary winding of the flyback (tried all and all polarities) and I hear the wine but no sparks.

I probably should try winding the primary winding myself right?


Some clip is blocking most of the space I hope spacing of the windings aren't very important.

Thanks in advance.
mod edit- oversized images

Re: Is this flyback suitable?
Steve Conner, Sat Apr 07 2007, 10:12PM

Oi! Your pictures are way too big! I resized them.

Re: Is this flyback suitable?
uzzors2k, Sun Apr 08 2007, 09:54AM

You should be able to fit a small primary on there, try 8 turns for 12V, and drop some turns until the 2N3055 starts heating. If you run out of space just take the core off and grind off the excess plastic. The other wires are lower high voltage lines, and can be ignored. (don't touch them though!) Bring the HV wire (the fattest one) to the pins on the bottom of them flyback and one of them will arc to the HV wire. That is your ground wire. You can try the internal primaries first if you like, they will produce some sparks too.

Re: Is this flyback suitable?
Sparkie, Sun Apr 08 2007, 12:53PM

Hey I was using a 5-7amp 13.8v psu to run my flyback, but last night while messing with it, the arc halfed in size, then 2 seconds later, a capacitor exploded in the psu. It was a small 47uf 16v electrolytic. I have replaced with a 47uf 35v. My question is, how can I stop these high voltage spikes going back into the psu? Maybe wrap the + and - 12v wires in two ferrite rings like you would use for RF, or would that not work. I have also been using a 12v 7AH Gel cell, any fear of that exploding?!

Also, if I build the zvs driver or the 555 driver, will they still send HV spikes out the 12 end?

Also added some pics of it all boxed up.

Thanks for all your help!







Oh and yes, i have now made the primary from thicker wire, made a slight improvement, and don't run as hot.

Re: Is this flyback suitable?
Dr. Dark Current, Sun Apr 08 2007, 01:58PM

Put a filter capacitor of reasonable size (at least 2200uf) across the output of your power supply.

Re: Is this flyback suitable?
Sparkie, Sun Apr 08 2007, 02:23PM

Thanks jmartis. What kind of voltage? I have a 10,000uf 35v High-ripple, will that do? Will the HV spikes not damage that, I wouldnt want that to explode! Safe to build it into my box? Also, is it correct that I should ground one half of the secondary? Won't that put HV into my 12v negative?

Thank you!

Edit: Heres a vid of it running off 14v. Im quite impressed!!

Re: Is this flyback suitable?
Dr. Dark Current, Sun Apr 08 2007, 07:59PM

Of course the capacitor must be higher voltage than your power supply, but doesn't have to be much higher. Your cap will certainly do it.
Ground the negative secondary output to mains ground.

Re: Is this flyback suitable?
Tonic, Sun Apr 08 2007, 08:23PM


How I can find out, which HV output is negative?

Re: Is this flyback suitable?
Sam, Sun Apr 08 2007, 08:52PM


2 neon bulbs in series over ( I think ) the base of the main drive transitor to the collector. there are 2x 3055 under there

Re: Is this flyback suitable?
Dr. Dark Current, Mon Apr 09 2007, 03:26PM

the pin on the base of the flyback (which you use to arc to) is the negative.

Re: Is this flyback suitable?
Sparkie, Mon Apr 09 2007, 03:47PM

Well, thank you all! Been playing with it today, and made a video up of some of the stuff I did. Check it out...

http://www.youtube.com/watch?v=JOTn7A4BFfs

Thanks all!