Flyback Cooling?

[Jon1967us]

Has anyone devised or utilized an effective way to cool the inside of the enclosed flyback cage in CTC models like the 16? A non destructive option, like drilling holes would be preferred.

[Electronic M]

I think I have seen people add fans and the like.

I just bought my first CTC-16 (I repaired one for somebody years ago) a couple of weeks ago. So I may be attempting to come up with my own solution soon.

[Eric H]

Lack of holes in the HV cover is probably for X-Ray protection. You could probably drill holes and place a piece of sheet metal over the holes with spacers to provide ventilation and still keep the Rays contained.

The X-Rays are probably too weak to matter in most cases.

[etype2]

This fan installed in my 21CT55 as an example. It’s wired to operate with the power switch on the set.

https://visions4netjournal.com/wp-co...7FA25009B.jpeg

https://visions4netjournal.com/wp-co...3E5E7C08D.jpeg

[damen]

Replacing the 3A3 with a solid state rectifier eliminates the X-ray source in the cage.

[old_tv_nut]

Originally Posted by damen

Replacing the 3A3 with a solid state rectifier eliminates the X-ray source in the cage.

The high voltage regulator tube is the possible source of X-rays, not the rectifier. The rectifier has peak voltage across it when it is not conducting. As a shunt regulator, the HV regulator has the regulated high voltage across it when it is conducting, and current that varies oppositely to the CRT current.

[Electronic M]

Originally Posted by etype2

This fan installed in my 21CT55 as an example. It’s wired to operate with the power switch on the set.

https://visions4netjournal.com/wp-co...7FA25009B.jpeg

https://visions4netjournal.com/wp-co...3E5E7C08D.jpeg

On my 21CT55 I didn't want to modify the HV cage so I bought a PVC pipe coupler roughly 3-4" in diameter (it matched the diameter of the desktop computer fan I used) and I glued the fan to the coupler, and set the coupler over and around the stock vent (it had about .5" clearance around the vent dust cover) so it would suck hot air out of the HV cage. A couple of wires from the mounting ears of the fan to the chassis hold it down so it doesn't easily move.
The best part is I can remove it easily and the HV cage goes back to stock with no ground off rivets or missing vent cover.

[Jon1967us]

Originally Posted by Eric H

Lack of holes in the HV cover is probably for X-Ray protection. You could probably drill holes and place a piece of sheet metal over the holes with spacers to provide ventilation and still keep the Rays contained.

The X-Rays are probably too weak to matter in most cases.

Yeah, I would agree with this as a possible approach. The problem with the 16 is it's fully enclosed, unlike the above referenced. There is no inlet or outlet.

I did a similar mod on my Hallicrafters T54 elevating the "roof" of the HV cage with standoffs.

[Jon1967us]

Originally Posted by old_tv_nut

The high voltage regulator tube is the possible source of X-rays, not the rectifier. The rectifier has peak voltage across it when it is not conducting. As a shunt regulator, the HV regulator has the regulated high voltage across it when it is conducting, and current that varies oppositely to the CRT current.

That's my understanding as well. The 6BK4 is the source of X-rays. And thats in an open topped enclosure!

[etype2]

This was our solution for the CT 7 Worthington. The idea was to direct 6BK4 heat away from the flyback.

https://visions4netjournal.com/wp-co...A21960C18.jpeg

BTW, the vent cover was retained from the 21CT55 and can be returned to the HV cage with a few grommets and screws, but I known that will never happen.

[Jon1967us]

Nice work. Like what you did there.
Did you use a cutting wheel or something to cut the hole?

Originally Posted by etype2

This was our solution for the CT 7 Worthington. The idea was to direct 6BK4 heat away from the flyback.

https://visions4netjournal.com/wp-co...A21960C18.jpeg

BTW, the vent cover was retained from the 21CT55 and can be returned to the HV cage with a few grommets and screws, but I known that will never happen.

[old_tv_nut]

Originally Posted by Jon1967us

That's my understanding as well. The 6BK4 is the source of X-rays. And thats in an open topped enclosure!

The 6BK4 is built to shield the X-rays from leaving the tube, but during the X-ray scare, some tubes were made with the guts installed crooked so that the X-rays were not totally blocked by the internal shielding. If your 6BK4 has internal elements that are visibly straight, it is probably not a problem.

[reeferman]

Don't sit so close to the TV or you will need glasses!

OK, Mom.

LOL

[Yamamaya42]

Originally Posted by reeferman

Don't sit so close to the TV or you will need glasses!

OK, Mom.

LOL

it was BECAUSE I sat too close to the TV, that my mom knew i needed glasses. :O