Just curious, is the CRT base loose? If so, high resistance connection could certianly be the problem. One of the filament leads may have pulled slightly out of the plug, possibly when the CRT socket was removed. Hopefully thats all thats wrong.

Ok, I tried reflowing the heater pins - no change, still reads about 180k. Pete Deksnis told me the 21AXP22A included arc fixes - that may be the high resistance I'm measuring if things are shorted internally???

Took off the neck hardware and yoke, pictures attached. I can't recognize a getter area - is it the thin light band between the black dag ring and the large black dag area on the neck funnel? That area is cloudy and looks orangish if you shine a flashlight through from the bottom.

Haven't figured out how the plastic shield cone and CRT are mounted yet, see four clips but not sure if the shield can be removed by itself. Anyway, the chassis will have to come out first. Hope to see more at Doug's place tomorrow - he has one with the chassis removed already.

BTW, i am repeatedly wiggling and tapping after each attempted fix - the base allows a tiny movement when you try to rotate it, but the ohmmeter doesn't budge no matter what

The 21AXP22A arc fix involved a high resistance internal connection to the HV (bell), so that an internal arc woul be less likely to do any damage, and eliminated the need for an external resistor in series with the ultor connection. Probably unrelated to you filament problem.

Scotty at Hawkeye is (I think) willing to attempt a 21AXP22 rebuild, but I suspect it would not be cheap. If you hunt around in the collecting circles, you will likely find one.

The tube has gone to air, the white ring is supposed to be black and shiny.

The heaters no doubt burned up when it was powered up with air in the tube. :sigh:

With no further comments coming in, I've decided I will hold onto this set for maybe a year at most while hoping to get a usable/rebuildable 21AXP22A.
When I get to the point of finally giving up, then free to a good home, the same terms I received it on. Too bad the face seal can't be fixed. :sigh:

Don't give up on this set yet. You have options. The glass 21CYP22 will work in this chassis with some slight mods. I believe many later 21" round tubes will also work in your CTC-5.

-Steve D.

Run some Wanted ads on the forums and on the ETF website. There is a good chance you will fina a 21AXP22 out there. And as Steve D says, you can always put a glass 21" crt in it.

Thanks for the encouragement! Not giving up yet, just trying to set some limits to get myself moving as much as anything else.

Here is the "cheap and dirty" cover I made. Thank you again, old_tv_nut, and good luck on finding a usable CRT for your CTC-5.

my RCA has one just like that :D

nice!

The 21AXP22A is at Scotty's and it looks like the rebuild will be attempted this week. He waits until there are several days with no predicted bad weather, since a power failure would cause problems with the oven.

I am still seeing if I can verify a list of caps for replacement. Doug drh4683 gave me a complete list, but I am still trying to locate them all and make up my order, especially a nuisance since RCA and SAMS numbered things differently.

Meanwhile, all I have accomplished is to remove the chassis and the CRT from the cabinet. I plan to remove the tubes and check them.

Any advice on cleaning the chassis would be appreciated at this point. Can this stand up to a wet cleaning, or should I not risk it? I know that is how Tektronix scopes used to be refurbished, but they also may have replaced controls or other things that I wouldn't want to risk having to replace en masse.

Congrats! You have been most definitely blessed! Can't wait to see more pics. I hope all goes well on the CRT rebuilding, my fingers are crossed.. Personally, I wouldn't do a wet cleaning unless there is no other choice. It may take more time to detail clean but it is better safe than sorry.

Clean chassis with compressed air jet and mild detergent in water soultion and a tooth brush. I would NOT use any more moisture than is necessary to spot clean with tooth brush to scrub and dry rags to wipe clean.

Did you send the original crt that lost vacuum to Scotty or did you find a dud under vacuum?

If you sent the original athat lost vacuum I would ask Scotty to seal the glass to metal seal with Vacseal prior to, and after the tube goes into the oven. It is a long shot but may help your rebuilt crt to hold vacuum.

Good Luck and let us know how the rebuild went.