Vintage Radio Modification

Discussion in 'General Electronics Chat' started by Art, May 22, 2008.

  1. Art

    Thread Starter Distinguished Member

    Sep 10, 2007
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    Hi Guys,
    I'm getting an old His Master's Voice radio tomorrow, and it probably requires
    a 9 or 12 Volt battery that isn't made anymore.
    I'm just wondering what the standard deal is for swapping battery connectors
    and battery holders.
    Is this the done thing?
    Or are you supposed to make some arrangement that fits to the original battery connector?
    Cheers, Art.
     
  2. Wendy

    Moderator

    Mar 24, 2008
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    I don't have a clue, but I would look into making an adaptor that would convert a modern style battery into an older style. Can you show the older battery dimensions?
     
  3. Art

    Thread Starter Distinguished Member

    Sep 10, 2007
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    61
    Not yet, but I suspect it will be one of those long rectangular ones
    with two push in terminals.
    I think 8 AA batteries could fit in it.
    I've seen one in another radio.
     
  4. Wendy

    Moderator

    Mar 24, 2008
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    Good luck. I love the old designs. If I didn't have so many other things going on I could see myself getting into that as a hobby.
     
  5. beenthere

    Retired Moderator

    Apr 20, 2004
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    Those old batteries like you describe might have been "B" batteries with a potential of close to 45 volts. If one of the terminals goes to a plate resistor, check the tube to see what it wanted for B+. There might have been an "A" battery or two. These were big cylinders of 1 1/2 volt output for the tube heaters.
     
  6. thingmaker3

    Retired Moderator

    May 16, 2005
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    Which battery is needed will depend on which of several RCA radio models you've got. Nipper's image was associated with nearly everything RCA made from the time they bought out Victor until the early sixties. My dad had a "his master's voice" radio with transistors, powered by a 9v PP3 battery.
     
  7. Art

    Thread Starter Distinguished Member

    Sep 10, 2007
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    I've got a hint that it is a transistor radio going by what Mum said,
    but who knows.. I'll find out today anyway. I'd love a working valve radio though.
    It might have actually said "transistor radio" on it since I imagine that would have
    been a selling point in the day.

    Not much of a hobby 'yet".. this one just happened to come my way.
    The only radio I fell in love with was an old STC floor standing model that belongs
    in a lounge room.
     
  8. beenthere

    Retired Moderator

    Apr 20, 2004
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    I'm too old if I don't see how a transistor radio can be classed as "antique". Better go for the 9 volt battery.

    By the way, we did have a 1950's vintage GE portable tube radio. Lots of thorium in the cathodes for emission, 1 1/2 volt heaters, and a "B" battery for the plates.
     
  9. thingmaker3

    Retired Moderator

    May 16, 2005
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    "Transistorized" was a definite selling point! Those radios were so darn tiny you could carry them like a college textbook!
     
  10. Art

    Thread Starter Distinguished Member

    Sep 10, 2007
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    I didn't call it antique :p just "vintage".
    Indeed there are certain HMV models that I'd just recirculate,
    but some are nice enough to hold on to.
     
  11. Art

    Thread Starter Distinguished Member

    Sep 10, 2007
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    Here it is:

    [​IMG]

    And this thing has multiple issues. First of all I know the speaker doesn't work!
    How unlikely is that?!
    Then there is some other problem which I think is one of the transistors.
    These transistors have BCE connections on the schematic inside the case,
    but the physical transistors all have four legs so I don't know how to replace one that looks burned.

    Considering their relatively low value on eBay, I would guess it's not worth putting
    a lot of effort into it.

    I'd like to know why the transistors have four legs though....
     
  12. thingmaker3

    Retired Moderator

    May 16, 2005
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  13. Art

    Thread Starter Distinguished Member

    Sep 10, 2007
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    I think that all of it's problems on the PCB are caused because the speaker went close to short circuit.
    Replacing it with an arbitrary PNP transistor didn't help.
    The fourth lead of all six transistors are connected to ground.
     
  14. studiot

    AAC Fanatic!

    Nov 9, 2007
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  15. Wendy

    Moderator

    Mar 24, 2008
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    That first link is just a graphic. Do they have a site?
     
  16. studiot

    AAC Fanatic!

    Nov 9, 2007
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