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Unfortunately, Tom's flyback suffered a catastrophic internal short in the primary winding. The heat generated actually caused the HV winding to slump. But there is still some hope. His flyback is in a box beside my workbench. It has been partly unwound, and the winding "recipe" recorded. I have not yet unwound the HV winding. This flyback is a bifilar wound type, with most of the primary and secondary windings wound with two wires in parallel. This makes it that much more difficult to attempt to rewind. The HV winding is a single strand of approx. AWG 38 wire.
I have wound 2 color flybacks so far, one for a 15" Motorola color set, and one for a CT100. The Motorola flyback works, but it has lower impedances than the original, and has a big "dip" in the top of the flyback pulse, which is causing some issues with the gated circuits. So just having the winding turns count recipe is not all there is. More experimentation will be required to attempt to determine what parameters need to change. As for the CT100 flyback, it too measures lower in inductance than the original, and if failed almost immediately upon installation in the set. Unwinding it did not reveal an obvious defect. I suspect wire handling is a critical issue.
I have taken a break from coil winding attempts for the last couple of months, it is just too darn hot out in the garage to slave over a hot winding machine. And other project have managed to get on the bench ahead of the coil winding. But in the next month or so I will get back to it, and see if I can make more forward progress.
Here is a photo of the winding machine, a George Stevens model 225-AMVP universal progressive coil winding machine, made in 1964. Some of you may have seen this at my ETF presentation on coil winding.
I will report progress as it is made.
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John Folsom
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