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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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23rd Jul 2020, 6:30 pm | #1 |
Heptode
Join Date: Aug 2016
Location: Dumfries, Scotland, UK.
Posts: 549
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Osram new music magnet 4. Battery connections and voltages help
I have an exceptionally tidy osram mm4 I don't usually do battery sets I could do with the following info what is the HT battery voltage PM2 fitted presumably output valve . Lt 4 volts I assume and what do I connect to SG I know it's screen what voltage and + - and where does the other connector from whatever battery it's attached to go ??
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23rd Jul 2020, 7:41 pm | #2 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: Osram new music magnet 4. Battery connections and voltages help
HT will be somewhere around 120 volts, screen grid around 60 to 80 volts, LT should be 2 volts, grid bias....not absolutely sure but say 9 volts -ve for starters but possibly lower.
Plenty of info on this receiver on this forum, here's a link to the schematics for the battery version and the mains version: http://www.electrojumble.org/DATA/Mu..._4_with_AC.pdf Lawrence. |
23rd Jul 2020, 8:02 pm | #3 |
Dekatron
Join Date: Jan 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 8,173
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Re: Osram new music magnet 4. Battery connections and voltages help
Hi lloyd, these set work well when operating and usually give little trouble apart from the I/V transformer which often has a winding OC.
Actual GB will depend on the OP valve fitted, and may be less than 9v, there is also an intermediate GB of 1.5 or 3 volts I believe. High Z speaker needed Ed |
23rd Jul 2020, 8:09 pm | #4 |
Heptode
Join Date: Aug 2016
Location: Dumfries, Scotland, UK.
Posts: 549
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Re: Osram new music magnet 4. Battery connections and voltages help
Thanks that nearly answered the question which was where does my GB connect to lol
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23rd Jul 2020, 8:15 pm | #5 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: Osram new music magnet 4. Battery connections and voltages help
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24th Jul 2020, 9:03 am | #6 |
Heptode
Join Date: Aug 2016
Location: Dumfries, Scotland, UK.
Posts: 549
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Re: Osram new music magnet 4. Battery connections and voltages help
Ah I seem to have a bit of a lash up in the GB dept see pics from the article on the set GB is attached to the transformer and one side of the capacitor next to it mine had a wire from the transformer to a resistor where the fuse bulb should be please see pics
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24th Jul 2020, 9:12 am | #7 |
Heptode
Join Date: Aug 2016
Location: Dumfries, Scotland, UK.
Posts: 549
|
Re: Osram new music magnet 4. Battery connections and voltages help
Ah I seem to have a bit of a lash up in the GB dept see pics from the article on the set GB is attached to the transformer and one side of the capacitor next to it mine had a wire from the transformer to a resistor where the fuse bulb should be please see pics
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24th Jul 2020, 9:40 am | #8 |
Dekatron
Join Date: Sep 2005
Location: Seaford, East Sussex, UK.
Posts: 5,997
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Re: Osram new music magnet 4. Battery connections and voltages help
Have you checked the intervalve transformer yet? I had to rewind mine https://www.vintage-radio.net/forum/...d.php?t=158892.
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24th Jul 2020, 9:57 am | #9 | |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: Osram new music magnet 4. Battery connections and voltages help
Quote:
I would go with a GB battery. Lawrence. |
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24th Jul 2020, 1:10 pm | #10 |
Heptode
Join Date: Aug 2016
Location: Dumfries, Scotland, UK.
Posts: 549
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Re: Osram new music magnet 4. Battery connections and voltages help
Transformer seems to be fine I'm going to disconnect the resistor and wire and put a battery in and see how we go.
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24th Jul 2020, 7:38 pm | #11 |
Dekatron
Join Date: Jan 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 8,173
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Re: Osram new music magnet 4. Battery connections and voltages help
Hi lloyd, the "flat cycle lamp batteries (LR12) and the adaptors that replace them and take 3, AA cells are good for this use and will fit into the clip for the GB battery.
Ed |
25th Jul 2020, 12:40 am | #12 |
Heptode
Join Date: Aug 2016
Location: Dumfries, Scotland, UK.
Posts: 549
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Re: Osram new music magnet 4. Battery connections and voltages help
I've soldered 3 AA batteries together and printed them out an appropriate period grid bias battery box shouldn't ever need to change it so I'm sure that'll be fine .
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