7YR772 Ch= 7B09A
Majestic Radio & Television Co.,(post 1932)
- Produttore / Marca
- Majestic Radio & Television Co.,(post 1932)
- Anno
- 1948 ?
- Categoria
- Radio (o sintonizzatore del dopoguerra WW2)
- Radiomuseum.org ID
- 197252
SAMS Photofact
Clicca sulla miniatura dello schema per richiederlo come documento gratuito.
- Numero di tubi
- 7
- Principio generale
- Supereterodina (in generale); ZF/IF 455 kHz
- Gamme d'onda
- Solo onde medie (OM).
- Particolarità
- Giradischi e registratore
- Tensioni di funzionamento
- Alimentazione a corrente alternata (CA) / 110-120 Volt
- Materiali
- Mobile in legno
- Radiomuseum.org
- Modello: 7YR772 Ch= 7B09A - Majestic Radio & Television Co
- Forma
- Soprammobile a cassapanca o cassetta, solitamente con coperchio (NON a leggio)
- Annotazioni
- Radio with Phono and Wire Recorder.
- Letteratura / Schemi (4)
- Photofact Folder, Howard W. SAMS (Set 42, Date 7/48, Folder 4812-17)
- Autore
- Modello inviato da Ernst Erb. Utilizzare "Proponi modifica" per inviare ulteriori dati.
- Altri modelli
-
In questo link sono elencati 418 modelli, di cui 174 con immagini e 358 con schemi.
Elenco delle radio e altri apparecchi della Majestic Radio & Television Co.,(post 1932)
Discussioni nel forum su questo modello: Majestic Radio &: 7YR772 Ch= 7B09A
Argomenti: 1 | Articoli: 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!
Allegati
- Majestic 7B09A Schematic (288 KB)
Bob Poole, 15.Dec.20