View Full Version : flyback info

08-21-2015, 07:48 AM
does anyone here know if a thordarson fly 355 is a 70 degree or 110 degree.

08-23-2015, 07:05 AM
what model is the fly for?

08-23-2015, 02:54 PM
well thats just it i dont know what set it goes to, because what i want to do is have a 70 degree fly for a set i dont have to use in the event one of my sets fly goes bad then i will use the donut and coil in the center and rebuild the one that goes bad. only if its a 70 degree for the roundies.

08-23-2015, 03:05 PM
As a source of wire, It's kinda expensive to buy one for that....
But you know all the wires/taps are all on the donut, so it
will all be different....


08-23-2015, 04:22 PM
You do know fly rebuilding has been tried before right? It didn't exactly go well...

Best thing is put in a fly that is close, and mod the circuits to accept any pulses that may be different. If the HV donut goes bad, some have used a tripler module off the horizontal output tube plate cap to get the anode voltage.

08-23-2015, 05:11 PM
We used to swap tires on flybacks all the time - and pulse windings as well. Most of the time it worked, but occasionally the pulse winding transplant didn't go well. We had a Motorola that wouldn't converge, and somehow the pulse winding on the fly was bad. Motorola had some tips about the gripe in a bulletin, and sure enough that was our problem. After swapping out the pulse winding, we had no color - the winding was from a different flyback, and the keying pulse was oddly shaped, so we had to break down and buy the whole flyback - the tire was still good on the old fly, and we kept it around for a while, but never had a use for it.

Some Thordarson Flys for roundies have the same schematic for the tire - probably just a mounting configuration difference, or the presence/lack of other stuff like a circuit board mounted to the fly or a focus or horizontal center pot.

I suppose the key is determining what set it is for, comparing schematics/HOTs, and trying from there. I'll see if I can scan my Thordarson info for the roundie flybacks (Fly 277, others). Maybe it might help someone..


08-23-2015, 05:13 PM
the coil and donut would stay together it would just be put on the hardware from the other fly that would have went bad. as long as its a 70 degree it should work fine because they all have the horiz centering tap wires and all the rest is the same for all roundies just that they have different hardware to fit what ever chassis it was designed for. i just need to get a fly that is 70 degree or a thordarson fly list that states which ones are 70 degree. i would not be doing anything to the donut or the coil it sits on except slide it off the pole its on and hook up the wires to the old flyback and that should do it.

08-23-2015, 10:17 PM
I did some research, and would do more but it's bedtime at the time of this writing!

Fits Magnavox chassis 704041-2, 704054-2,3,4,5, T962 series, many others. I'm guessing later models but somebody here will know.

08-24-2015, 06:14 AM
i need to know if its for a round tube or a flyback by thordarson for a round tube set.