Restoration begins on Ed Reitan's CTC-7

[Electronic M]

If the repair was successful it may have as much as decades more time left on the fly, assuming temp and current can be kept under control.

Part of me wonders if the copper corrosion is natural. I know this example is a good 30 years older, but I've done ~3-4 Philco 60 chassis cathedral radios (2 more waiting in the wings) and 2-3 of their loss leader cousins the 80 chassis (2 of those waiting my bench also), and all but one of them (a 60 chassis) had either the antenna transformer, osc transformer or both with corroded open windings (and these windings have a coating besides the wire lacquer sealing?/holding them to the forms)...Only one had the problem in the lead-in, the rest were mid winding...Sometimes with multiple opens. The first ones I fixed in a similar fashion to what your tech did, the rest especially the ones with multiple opens I just rewound the ~<20 turns with phono pickup wire. All these sets were ones with good original cabinets, not barn dwellers, yet still were like that.

[etype2]

Originally Posted by Electronic M

If the repair was successful it may have as much as decades more time left on the fly, assuming temp and current can be kept under control.

Part of me wonders if the copper corrosion is natural. I know this example is a good 30 years older, but I've done ~3-4 Philco 60 chassis cathedral radios (2 more waiting in the wings) and 2-3 of their loss leader cousins the 80 chassis (2 of those waiting my bench also), and all but one of them (a 60 chassis) had either the antenna transformer, osc transformer or both with corroded open windings (and these windings have a coating besides the wire lacquer sealing?/holding them to the forms)...Only one had the problem in the lead-in, the rest were mid winding...Sometimes with multiple opens. The first ones I fixed in a similar fashion to what your tech did, the rest especially the ones with multiple opens I just rewound the ~<20 turns with phono pickup wire. All these sets were ones with good original cabinets, not barn dwellers, yet still were like that.

Probably natural, but from the years and heat. Mike is concerned about the heat in the cage. It has no ventilation holes, unlike the CTC-2B. He is going to add ventilation by drilling holes and adding a fan.

When I asked Mike why RCA would engineer a flyback with no ventilation, I said was this a money grab to get repair tech's to the home, he said, "well the fly backs were readily available but possibly to minamize arcing."

[ohohyodafarted]

It is my opinion that copper wire corrosion in the HV cage is not uncommon. I had this problem on my Hallicrafter 820 set. I think this is exacerbated inside the HV cage due to corona that can cause ozone, which is highly corrosive. A small knick in the varnish covering the wire can expose bare copper which will oxidize over time and physically weaken the wire.

[etype2]

Originally Posted by ohohyodafarted

It is my opinion that copper wire corrosion in the HV cage is not uncommon. I had this problem on my Hallicrafter 820 set. I think this is exacerbated inside the HV cage due to corona that can cause ozone, which is highly corrosive. A small knick in the varnish covering the wire can expose bare copper which will oxidize over time and physically weaken the wire.

Thanks. The insulation broke away with very little effort exposing this broken wire coming out of the windings.

After repair.

[Josef]

Nice, but I would j hook the copper wire to make the connection long term stable. In your case it could be better not to touch the connection any more to avoid further damage. I usually clean flybacks (from our european b&w sets) with WD40 to protect them from moisture and soften dried out isolations. Take care if there are carbon track pots and don't use WD40 in this case.

[colorfixer]

Originally Posted by Josef

Nice, but I would j hook the copper wire to make the connection long term stable. In your case it could be better not to touch the connection any more to avoid further damage. I usually clean flybacks (from our european b&w sets) with WD40 to protect them from moisture and soften dried out isolations. Take care if there are carbon track pots and don't use WD40 in this case.

I would be really afraid of using something as explosive as WD40 near anything high voltage or capable of arcing.

[Electronic M]

Originally Posted by colorfixer

I would be really afraid of using something as explosive as WD40 near anything high voltage or capable of arcing.

WD40 isn't explosive as an applied coating...heck it won't even explode if you shoot the spray through the flame of a lighter as I have done... It'll just burn energetically and give you a nice flame thrower for toasting jumping spiders.

Wet WD40 isnt that easy to light either. Many years ago I was trying to fix a 30s fan that I eventually found had a bad contact brush and it was arcing like crazy but not easy to keep enough WD40 on the rotor to sustain burn for more than a couple seconds.