7YR772 Ch= 7B09A
Majestic Radio & Television Co.,(post 1932)
- Country
- United States of America (USA)
- Manufacturer / Brand
- Majestic Radio & Television Co.,(post 1932)
- Year
- 1948 ?
- Category
- Broadcast Receiver - or past WW2 Tuner
- Radiomuseum.org ID
- 197252
SAMS Photofact
Click on the schematic thumbnail to request the schematic as a free document.
- Number of Tubes
- 7
- Main principle
- Superheterodyne (common); ZF/IF 455 kHz
- Wave bands
- Broadcast only (MW).
- Details
- Record Player + Tape Recorder
- Power type and voltage
- Alternating Current supply (AC) / 110-120 Volt
- Material
- Wooden case
- from Radiomuseum.org
- Model: 7YR772 Ch= 7B09A - Majestic Radio & Television Co
- Shape
- Tablemodel, Box - most often with Lid (NOT slant panel).
- Notes
- Radio with Phono and Wire Recorder.
- Literature/Schematics (4)
- Photofact Folder, Howard W. SAMS (Set 42, Date 7/48, Folder 4812-17)
- Author
- Model page created by Ernst Erb. See "Data change" for further contributors.
- Other Models
-
Here you find 418 models, 174 with images and 358 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
All listed radios etc. from Majestic Radio & Television Co.,(post 1932)
Forum contributions about this model: Majestic Radio &: 7YR772 Ch= 7B09A
Threads: 1 | Posts: 5
I'm working on my Majestic 7B09A, my first full restoration. As I am going through the unit doing a recap, I have run across a capacitor that I think is the dreaded "death cap", but I'm not sure. It's C14 (.1 uf, 250 volt), which the Photofact lables as a "Line Isolation" capacitor. It's tied between chassis ground (as is one side of the input AC) and B-, with a 220K resistor across it. I'm attaching the schematic for reference and I've circled the section in question.
I'm thinking this cap needs to be replaced with a Safety Cap. I researching them, it appears that only X2 caps come in the .1 value, which would make this application "across the line". However, the connection to B- is causing me confusion, as this point is the only reference to B- and uses the Earth Ground symbol, which is used throughout the rest of the chassis circuitry.
Is B- actually a DC circuit ground point and the .1 cap is providing noise filtering between it and the AC line?
Man, I've got a lot to learn, but this is so much fun!
Attachments
- Majestic 7B09A Schematic (288 KB)
Bob Poole, 15.Dec.20