CTC16 Flyback Cooling

[Findm-Keepm]

Originally Posted by Arcanine

So it looks like Tom (Electronic M) has brought life back to my CTC16 that I regretted buying. I was so mad about it I didn't even want to touch it. Long story there.

The one thing I noticed, and Tom did as well, is the flyback get's very hot after awhile and starts to drip wax. This is about after an hour on for him, and an hour on for me when I noticed it was hot. It's set correctly and Tom will chime in on that, or you can check the last parts of the CTC16 thread and see.

Do RCA Fly's just run really hot? And if so, would it hurt anything if I cut open the flyback box and installed a small computer fan to it externally, to suck cool air though the box so the Fly isn't sitting in there melting it self to death?

They do run warm, but if you have melting/dripping wax, one of three problems come to mind:

1. Too much cathode current through the 6JE6/6LQ6 - should be less than 250mA, preferably the lowest the efficiency (linearity) coil will adjust to.

2. The horizontal drive signal is mis-shapen. Caps, out of tolerance resistors, or a weak 6CG7/6FQ7 can cause the "on" time to increase, which ups the current through the fly.

3. Too much load on the fly - bad/wrong boost rectifier (it requires a "fast" rectifier for Boosted B+, a typical silicon diode won't do), bad focus rectifier (my CTC16 has an R-2AV2 silicon replacement, eliminating the focus rectifier filament load from the fly), and even a shorted turn or two in the focus coil can increase the focus current, but still yield good focus range. You can also eliminate the filament load from the 3A3C by using a R-3A3/ECG508 silicon replacement.

Also, make sure the B+ is the correct level - today's higher line voltages increase all the voltages in vintage sets. A dropping resistor add (complicated) or running on a variac (easiest - set it for 110 VAC and you should be good) are suggested as fixes.

Cheers,