Quote:
Originally Posted by Chris K
Last comment from me as I feel the "SEPARATE SUBJECT REQUIRED!" wrist slap is on its way!
I read several of them and they are fascinating. In addition, I'm a little apprehensive about the health and longevity of my TVs with a flyback winding exposed by cracking and/or melted wax. I have several Philco restorations that have that era of flyback and I have a designer, special edition Hallicrafters 7" that exhibits the heat related fading brightness symptom. I think I should probably get to them with some corona dope sooner rather than later.
I suppose the most efficient way to drag varnish into the windings is to match the base solvents as closely as possible.
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Nobody has had any luck with fixing the original HV osc transformers in 7" halicrafters. Easiest thing is to find a Motorola TS-4 or TS-18 chassis set (the most common electrostatic TV) with a dead CRT or cabinet beyond restoration and steal the HV transformer from it. Copy the Motorola HV osc circuit but use a 8BQ5 instead of a 25L6. Replace the 6C4 heater with a resistor. The Hallicrafters has a split heater string that converges at the 6X5s hot heater pin (it's other heater pin goes to ground). Ungrounf the 6X5s grounded heater pin and insert the 8BQ5 heater between that and ground. I did this modification on my Hallicrafters and it's been solid ever since.