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View Full Version : 12JP4 & 12LP4 - Interchangeable?

M3-SRT8
02-23-2009, 07:58 AM
In a DuMont RA-103 "Savoy?"

Inquiring Minds, Want To Know...

LJB:smoke:
jeyurkon
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/Sylvania/SylTubSubstManual1953.pdf

John
Eric H
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
02-23-2009, 04:16 PM
OK, Boys. Thanks!

LJB:smoke:
tvdude1
02-25-2009, 07:21 PM
OK, Boys. Thanks!

LJB:smoke:

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
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
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:smoke:
Tony V
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