ok while i am waiting on a 21AXP22,i would like to try and fit a 21FB22 into this set for test purposes,(ctc-5) it has a faceplate,has anyone ever tried to stuff one of these tubes in this type of set without any cutting or altering hardware?i dont think i will try and take off the faceplate,it test perfect,like new..
any suggestions??
oops..!! almost forgot also,what have you guys used for glue one the base of CRT's? I know it cannot be a conductive type because of the focus pin..
thanks
terry

...

Hi Terry,
My CTC-5 has a 21Cyp22 glass tube in it. I didn't install it but it looks to have all the 21AX mounting hardware. I imagine the 21FB should drop right in. The 21AX does have a metal flange that rests on the backside of the mask. You should probably pull the 21AX and measure the diameter, (the bulb face not the flange) vs. the 21FB. The only hangup might be mounting without the flange to secure it. Of course you must rest the cabinet on its face to remove and install the pix. tube. And follow safety precautions. Some one else can address any electronics differences such as high voltage connection and voltage differences.
Could be a fun project.

Terry,

If the crt base is just loose and wiggly but still connected I'd go the crazy/super glue route. That is what I use. If you have had the base completely off and are putting it on clean, use RTV clear silicone. That is an excellent HV insulator when cured and won't ever let go. Many of the really high powered spherical faceplate RCA projection CRT's from the Lancaster, PA plant had their socket bases completely filled with this stuff, but that was the 2-part silicone potting compound.

Rob

Terry,
I just read in an old RCA tech paper that when a 21AXP22A was replaced with a 21CYP22A a special kit had to be ordered from RCA. It contained new mounting hardware for the conversion. This may affect your planned tube swap.:(

...

Andy,

On close inspection of my CTC-5 with the 21CYP22 in place of the 21AXP22A, there is absolutely no modification of the mask.
The 21CY sits just behind the mask. The tube sides are fully exposed but the top and bottom are slightly masked. I believe RCA ads stated the CTC-5's with the 21AX as having 254 sq.in. and the CTC-7 with a 21CY with 260 sq. in. of viewable picture. The CTC-7 mask most likely has a slightly larger opening to account for the difference. And also explaines why the extreme top and bottom of the 21CY conversion in my 5 is not viewable.