Admiral 14UY3C Chassis CRT Question

[Chris K]

Steve M has two 14RP4 CRTs in stock and my Sams covers chassis for both the B and C versions in a single document. I have the 14UY3C version and the Sams lists 2 CRTs...14RP4 and the 14RP4A which I'm assuming is the aluminized version and that one fits the B chassis and one fits the C chassis.

Are these CRTs interchangeable or does anyone out there know what tube is the correct one for the 14UY3C version of the chassis?

Thanks
Chris

[Electronic M]

Originally Posted by Chris K

Steve M has two 14RP4 CRTs in stock and my Sams covers chassis for both the B and C versions in a single document. I have the 14UY3C version and the Sams lists 2 CRTs...14RP4 and the 14RP4A which I'm assuming is the aluminized version and that one fits the B chassis and one fits the C chassis.

Are these CRTs interchangeable or does anyone out there know what tube is the correct one for the 14UY3C version of the chassis?

Thanks
Chris

Generally speaking CRTs with a suffix letter and ones without are almost always interchangeable. There's probably a couple of 14" tubes with different middle letters that interchange too. Getting a tube substitution guide book helps with things like this... I'd consult mine but it's in a different building at the moment.
The A could be aluminization, but it could be other subtle (unimportant to compatibility) changes like a different phosphor white balance or a different style of bent gun that is electrically compatible with the original.
If you loose aluminization and need a trap I and others here can supply you with one...If you gain aluminization just remove the trap from the old tube and keep it in case another set you get ever needs it.

[Chris K]

CORRECTION!!! I have the 14YP3C Chassis but the same question applies...which tube, 14RP4 or 14RP4A?

[Chris K]

Originally Posted by Electronic M

Generally speaking CRTs with a suffix letter and ones without are almost always interchangeable. There's probably a couple of 14" tubes with different middle letters that interchange too. Getting a tube substitution guide book helps with things like this... I'd consult mine but it's in a different building at the moment.
The A could be aluminization, but it could be other subtle (unimportant to compatibility) changes like a different phosphor white balance or a different style of bent gun that is electrically compatible with the original.

Thanks Tom. I made a correction to the chassis number in my latest post but according to the sams for that chassis, there's still the same choice. The tube in my TV I believe says 14RP4 but the label is pretty jacked up so I'm not entirely certain.

[dieseljeep]

Originally Posted by Electronic M

Generally speaking CRTs with a suffix letter and ones without are almost always interchangeable. There's probably a couple of 14" tubes with different middle letters that interchange too. Getting a tube substitution guide book helps with things like this... I'd consult mine but it's in a different building at the moment.
The A could be aluminization, but it could be other subtle (unimportant to compatibility) changes like a different phosphor white balance or a different style of bent gun that is electrically compatible with the original.
If you loose aluminization and need a trap I and others here can supply you with one...If you gain aluminization just remove the trap from the old tube and keep it in case another set you get ever needs it.

The original 14RP4, whether it is aluminized or not uses an ion trap. Same is true with the other CRT's at the time. Later on, the OEM's and the rebuilders all seemed to be using the straight guns that didn't require an ion trap.
The tube was labelled, "no ion trap required".

[jr_tech]

CRT Data here:

https://frank.pocnet.net/sheets/168/1/14RP4.pdf

jr

[dieseljeep]

Originally Posted by jr_tech

CRT Data here:

https://frank.pocnet.net/sheets/168/1/14RP4.pdf

jr

That information is dated 1957!
Starting in about 1958-59, all new issue CRT's seemed to be straight gun tubes.
Example: 21ALP4 became 21CBP4, 17AVP4 became 17CFP4. Around the same time many new CRT's were becoming 110 deg types that didn't need one.
Then some of the CRT's made were 8.4 volt 450ma that added more confusion.

[Chris K]

I received an email from Steve that they are interchangeable. Yippee!

[Chris K]

I'm trying to coordinate a purchase with the ETM of a new 14RP4. In the meantime, I've been doing some work on the original tube. This is the one I mentioned a while back with the loose end cap. I de-soldered and re-soldered the CRT leads and put my Super Mack Sencore on it and it still showed it to be deader than dead. I let it sit for about half an hour at 6.3v and it did not improve noticeably so I bumped the voltage up to 8 volts for a little bit. Bang! Emissions suddenly went up significantly into the good area. I brought it back down to 6.3 and it held good emissions down to 4 volts. I think something is funky. No shorts but there's still no cutoff and the tube gets warm, warmer that any 6.3v CRT I have tested on the glass around the filament. I'll test it in the TV as soon as I've done some chassis work but any ideas what might be going on with it? Thanks!