Picture Tubes



Pre War Experimental and Prototype Picture Tubes



1934  5" Prototype

This CRT is dated 1/22/34. The tube was damaged at the base at some point and lost vacuum.  Probably was used to experiment with magnetic deflection.


Very simple gun structure, only 4 connections.



1934  9" Prototype

This CRT is dated 3/26/34. Possibly another test tube for magnetic deflection systems. This tube appears to still be under vacuum.


The gun structure is the same as the 5" tube above.


C-739  9" Experimental CRT

This tube has one set of deflection plates, it was used in the 1933 test sets. This test set was an improvement over the 1932 set, as it was designed to use one tuning system for video and sound, unlike the previous set which used two separate receivers. Also the 1933 set was designed for 240 lines vs. the 120/180 lines for the 1932 set. This tube used magnetic deflection for the vertical sweep and electrostatic deflection for the horizontal sweep. At this time in television development there were no power tubes available that could supply the current required to drive the magnetic deflection field at the frequencies required.  This tube appears to be still under vacuum. This CRT is dated 10/20/36, probably when it was put in storage vault.


Connections to the horizontal deflection plates on the neck of the tube.


C-745D 5" Experimental CRT

This tube was developed for the RR-366 field test set. See picture below. Unfortunately this tube has gone to air, apparently from a bad seal as there are no cracks or any other obvious faults.


Marketing cut sheet of the RR-366 chassis and picture tube.



Pre War Production Picture Tubes



5BP4 (1802-P4)

This CRT was used in many of the prewar 5" televisions, RCA TT-5 & TRK-5, Meissner 10-1153, GE HM171 & HM185. It is a very poor performing tube, even a NOS tube will have a very dim display.
Electrostatic deflection; electrostatic focus.


9AP4 (1804-P4)

This CRT was used in the prewar RCA TRK-9/90.
Magnetic deflection; electrostatic focus.



 This particular 9AP4 came from the RCA archives in Camden. The label carries numerous identification numbers. The L-2041 may have referenced an inventory or project, C-730P is the sequential number that was given to developmental CRT's by RCA, 1804-P4 is the commercial designation. Then the date which appears to be Jan  11,1939, the initials I have no idea, last is "South Vault" possibly where the tube was stored.
The bad news is that the tube is no longer under vacuum.



12AP4 (1803-P4)

This CRT was used in RCA TRK-12, Andrea 2F12, and virtually all prewar 12" mirror in lid televisions.
Magnetic deflection; electrostatic focus.


This is the 12AP4 in its protective cardboard cover, the tube was shipped this way. When it was installed in the television the front cover was removed and the cone section was kept with the tube, notice the cutout for the HV lead.



This CRT is used in DuMont prewar sets as a replacement for the prewar 14AP4 and 144-9-T CRT's.
Electrostatic deflection; electrostatic focus.



Post War Production Picture Tubes




This CRT is used in the Pilot TV-37, the first set sold for under $100.
Electrostatic deflection; electrostatic focus.


3NP4 (MW6-2)

Projection CRT used in Protelgram projection units. The Protelgram was used by many manufacturers, Emerson, Decca, Scott. The face of the CRT is spherical to match the curvature of the mirror that was used in the Protelgram. A version of this tube with a flat face (MW6-4) was also produced that was used with a direct lens projection system.
Magnetic deflection; magnetic focus.



Projection CRT used in all RCA projection sets and most other projection televisions from 1946 - 1949. Anode voltage 25KV.
Magnetic deflection; electrostatic focus.



Second generation projection CRT, replaced the 5TP4 in projection sets through the mid 50's. Due to the 40KV anode voltage this tube used, the high voltage lead was molded on to the tube.
Magnetic deflection; electrostatic focus.



This CRT was primarily used in the RCA 621 set.
Magnetic deflection;  electrostatic focus.





This CRT is used in early 7" sets, in particular the Transvision kits.
Electrostatic deflection; electrostatic focus. It is electrically identically to the 5BP4 shown above.



This CRT is used in virtually all 7" sets from 1948 until the early 50's.
Electrostatic deflection; electrostatic focus.



This CRT is electrically identical to the 7JP4 except for the screen size.
Electrostatic deflection; electrostatic focus.



This CRT is also electrically identical to the 7JP4 except that the screen is a full 10" diameter. Raytheon built this tube for use in their console.
Electrostatic deflection; electrostatic focus.



This CRT is the most commonly used picture tube, used in virtually every 10" set from after the war until the early 50's.
Magnetic deflection; magnetic focus.



This CRT is the aluminized version of the 10BP4, used primarily by GE and Farnsworth as original equipment.
Magnetic deflection; magnetic focus.



Like the 10BP4 above this is the most common 12" CRT found in late 40's and early 50's televisions. The 12KP4 is the aluminized version of the 12LP4
Magnetic deflection; magnetic focus.


15AP4 (First Style)

This CRT was used in early production DuMont sets. Notice the "bump" between the neck and the main bulb, similar to the prewar 12AP4.
Magnetic deflection; magnetic focus.



15AP4 (Second Style)

This CRT is used in DuMont sets. The "bump" is gone, and the form is the same as other CRT's of the era. Notice that DuMont continued to use the "button" style HV connector found on non television CRT's.
Magnetic deflection; magnetic focus.