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Antique Radio Technical Forum
Majestic Model 70B

Posted by Terry on 11/05/2005 15:25

::I have a Majestic radio model 70B with 7P6 power supply. The voltages are present for the 5Vpower, 1 1/2 V A.F, 2 1/2 det and 1 1/2 RF, but no +50, +96 or +260. All of the tubes light up and the radio is in very good shape (the old wiring has been replaced).
::
::I suspect the transformers that generate these voltages or a "common" feed to these transformers.
::
::I would appreictae any information that anyone can share. I have .pdf files of the chassis showing graphics as well as a schematic.
::
::Grigsby-Grunow Co.
::Model: 70B
::Power:
::Chassis:
::Circuit:
::Year: Pre 1932
::IF:
::Tubes:
::Bands:
::Resources
::Riders Volume 1 - MAJESTIC 1-5
::Riders Volume 1 - MAJESTIC 1-10
::Riders Volume 1 - MAJESTIC 1-24
::Courtesy Nostalgia Air
::Courtesy Nostalgia Air
::Courtesy Nostalgia Air
::Courtesy Nostalgia Air
::
::I am persistent and not ready to give up on bringing this radio back to life.
::
::Thanks in advance for all of your help.
::
::Terry
:
:Hi Terry,
:
:One of the first things I would check would be continuity of the speaker field winding. If it is open you will not get any +B voltages.
:
:Radiodoc
:
Radiodoc,
I have continuity from the LARGE pins on the 80 tube rectifier to the speaker and have continuity of the speaker.

When I measure the AC voltage at the large pins of the 80 tube I get 3.8V and 356V at the small pins. Is this 400 ohm resistor in the bottom part of the power supply?

Any help woul be appreciated.

TF


Majestic Model 70B 
Terry 11/03/2005 20:06 
Norm Leal 11/04/2005 08:51 
Radiodoc 11/04/2005 09:12 
Radiodoc 11/04/2005 13:07 
Terry 11/05/2005 15:25 
Radiodoc 11/05/2005 20:40 
Terry 11/06/2005 20:54 
Radiodoc 11/07/2005 10:42 
Terry 11/07/2005 19:48 
Radiodoc 11/07/2005 21:43 
Terry 11/08/2005 20:57 
Radiodoc 11/09/2005 10:23 
Terry 11/09/2005 20:07 
Terry 11/09/2005 21:16 
Radiodoc 11/10/2005 08:58 
Terry 11/10/2005 21:11 
Radiodoc 11/11/2005 14:11 
Terry 11/11/2005 20:50 
Radiodoc 11/11/2005 22:22 
Thomas Dermody 11/12/2005 01:52 
Terry 11/12/2005 19:34 
Radiodoc 11/14/2005 10:07 
Terry 11/14/2005 19:31 
Radiodoc 11/14/2005 22:26 
Terry 11/15/2005 19:23 
Radiodoc 11/15/2005 20:22 
Terry 11/16/2005 08:02 
Radiodoc 11/16/2005 08:43 
Terry 11/16/2005 13:13 
Radiodoc 11/16/2005 15:09 
Terry 11/16/2005 20:40 
Radiodoc 11/17/2005 09:05 
Thomas Dermody 11/17/2005 17:09 
Terry 11/17/2005 20:44 
Thomas Dermody 11/18/2005 00:32 
Thomas Dermody 11/18/2005 02:43 
Thomas Dermody 11/18/2005 12:19 
Terry 11/30/2005 20:09 
Thomas Dermody 11/30/2005 23:38 

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