Indentity unknown

I found a pencil written 185r4 on the chassis. I think they are both that as it was written twice on the chassis.
Thanks, Rickey

Yes they control the voltage so the other heaters have time to warm up without an inrush of current.

I assume they both were functioning in the circuit. Could one just be only like a filament only?
Thanks, Rickey

It is possible to have two ballast tubes, sometimes they did that just to increase the advertised tube count.

Thanks Cliff, the radio has six sockets, one is missing and one is not readable. I think the missing one and unmarked one are both ballast tubes? The missing tube is a 4 pin as is the ballast shown.
Rickey

Are there 5 or 6 tube sockets?
If 5 sockets then just look on the list to find the possible missing tube. Look at the missing tube sockets pin connections and what they connect to.
If 6 sockets then the ballast tube may be one of the ones listed, is there a brand name on the unidentified tube?
Were you wanting to know if that one unidentified tube is a part of that set?, or just trying to find out what kind of tube it is separately?
also look for metal stamping numbers and ink stamped numbers on the chassis. May give a clue.
Here's some possibilities to look at:
Company Trade Name- Model -Chassis -# Tubes -Tube List -Ballast
-----------------------------------------------------------------


Radolek Company- R17568-5- 6C6, 6D6, 25Z5, 43, 76- L49B
-------------------------
Halson Radio Manufacturlng Corp.-Halson- T11-5- 6C6, 6D6, 6U5/6G5, 25Z5, 43- L49B

-----------------
International All-Wave Radio Corporation
66X
5
2-6D6, 6C6, 43, 25Z5
65R4
----------------------------
International All-Wave Radio Corporation
76, 76X
5
2-6D6, 6C6, 43, 25Z5
165R4
--------------------------
International All-Wave Radio Corporation
86
5
2-6D6, 6C6, 43, 25Z5
165R4
-------------------------
International All-Wave Radio Corporation
96
5
2-6D6, 6C6, 43, 25Z5
165R4
-------------------------
International All-Wave Radio Corporation
617
5
2-6D6, 6C6, 43, 25Z5
165R4
---------------------------
International All-Wave Radio Corporation
676
5
2-6D6, 6C6, 43, 25Z5
165R4
-----------------------
Kadette Radio Corporation
International, Kadette
K617
5
6C6, 2-6D6, 25Z5, 43
165R4
----------------
Kadette Radio Corporation
International, Kadette
66X, 86, 96
5
6C6, 2-6D6, 25Z5, 43
165R4
----------------
Kadette Radio Corporation
International, Kadette
76, 76X, 676, 676X
5
6C6, 2-6D6, 25Z5, 43
165R4
--------------------------------
Majestic Radio And Television Corporation
Majestic
50
5
6C6, 6D6, 25Z5, 43
Ballast tube
-------------------
Clinton Manufacturing Company
Clinton
610SP, 611SP
5
76, 6D6, 6C6, 43, 25Z5
65R4
--------------------------
Federated Purchasers, Inc.
Acratone
216K
5
6C6, 6D6, 25Z5, 43, 76
165R4
------------------------
Air King Products Company, Inc.
Air King
701, 702, 703
5
6D6, 6C6, 43, 25Z5
M55HG
-------------------------
Air King Products Company, Inc.
Air King
710
5
6A7, 6D6, 6C6, 43, 25Z5
M49HG
-----------------
Air King Products Company, Inc.
Air King
715
5
6A7, 6D6, 6C6, 43, 25Z5
M49HG
-------------
Air King Products Company, Inc.
Air King
701
5
6C6, 6D6, 6E6, 25Z5, 43
M30HG (2)
---------------------
Air King Products Company, Inc.
Air King
710, 715, 720
5
6A7, 6C6, 6D6, 25Z5, 43
M49HG
------------------
Allied Radio Corporation
Knight
A9740
5
6D6, 6C6, 43, 25Z5
L55B
-----------------------
Automatic Radio Manufacturing Co.
Automatic, Tom Thumb
911
5
6C6, 6D6, 25Z5, 43, 76
BM49B
------------
Automatic Radio Manufacturing Co.
Automatic, Tom Thumb
920
5
6C6, 6D6, 6U5/6G5, 25Z5, 43
BM49B
--------------

that looks like it could be a ballast tube.
The four pin tube would only indicate its age at this point, however with the tube numbers supplied, there is a web page called grillcoth.com or .org that has a very nice database that you can plug tube numbers into and it will list tubes of that compliment along with the radio model. After you get the model if any than you can go to Beitmans, or Riders and find tubes in the same schematic, if the listed tubes come back then you can see what the missing tube may be.

I don't have a lot of time to do this but that may help you. I will take a quick look though.

This is a picture of the tube I can't identify. This still leaves the unknown 4 pin tube.
Rickey.

This radio has six tube sockets. It has a missing 4 pin tube. I can only identify 4 tubes.
43-25z5-6c6-6d6. I have a picture of the one that has no number on it. The label says Plant A, Chicago. Thanks, Rickey