12JP4 & 12LP4 - Interchangeable? - Videokarma.org TV - Video

M3-SRT8 · #1 02-23-2009, 07:58 AM

In a DuMont RA-103 "Savoy?"

Inquiring Minds, Want To Know...

LJB

jeyurkon · #2 02-23-2009, 09:22 AM

If memory serves, the Savoy has the 12JP4? If so, then in going to the 12LP4 you need to add an double field ion-trap, change the anode connector, and make sure the dag coating is grounded. The 12JP4 doesn't have this coating, supposedly. You need to be able to accommodate a slightly different bulb diameter.

http://tubedata.itchurch.org/other/S...Manual1953.pdf

John

***Eric H*** · #3 02-23-2009, 10:28 AM

I believe the 12LP4 is longer for the Ion trap, if the cabinet has room for it then it'll work

M3-SRT8 · #4 02-23-2009, 04:16 PM

OK, Boys. Thanks!

LJB

tvdude1 · #5 02-25-2009, 07:21 PM

Quote:

Originally Posted by M3-SRT8

OK, Boys. Thanks!

LJB

The best swap over is the 12qp4. Fits correctly against the yoke and no anode swap. I have one in my 103 Dumont.

John Folsom · #6 02-26-2009, 09:06 PM

All the DuMont RA103s I have worked on came with 12LP4s as replacements for the original 12JP4.

M3-SRT8 · #7 02-27-2009, 06:13 AM

OK. Next Question:

In case I NEED one, Does anybody have a line on any of these CRT's?

LJB

Tony V · #8 02-27-2009, 10:55 PM

There was a NOS one up for bids on the auction site this week. I think the auction is over now though but you can check.
-Tony