Transformer pin out on a radio receiver

Discussion in 'Technical Repair' started by Klaidas Stumbras, Aug 20, 2016.

  1. Klaidas Stumbras

    Thread Starter New Member

    Jul 7, 2016
    14
    1
    Hello i need help to figure voltages on these wires coming from transformer.The transformer stopped working after rain and thunder then i opened the radio (seen in the picture below) and checked the transformer and i figured that the main HV side of transformer has no continuity when checked with multimeter however the low side of the transformer has continuity.
    Yellow and Blue wires have = 31,5 ohm
    Yellow and Red wires have = 31,5 ohm
    Yellow and Black wires have = 26,3 ohm
    Red and Black wires have = 6 ohm
    Red and Blue wires have = 11,2 ohm
    Black and Blue wires have = 6 ohm

    Seem odd that all of the wires are connected together ... i dont know maybe all the coils are blown ? HELP
     
  2. SLK001

    Well-Known Member

    Nov 29, 2011
    817
    227
    I doubt it. Plug in the primary side and measure the voltages on the secondary windings. The inside of the radio doesn't look wet, so it could be something else.
     
  3. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,542
    2,369
    Those transformers have a small thermal fuse embedded in the winding, in some cases you can see the ends poking out and short them across, this has to be confirmed with a resistance check to the pri winding.
    You could then fuse the primary externally with a tight value.
    Max.
     
  4. Klaidas Stumbras

    Thread Starter New Member

    Jul 7, 2016
    14
    1
    the primary side is dead
     
  5. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,542
    2,369
    See post #3!!
    If it has one, the thermal fuse is blown.
    Max.
     
  6. Klaidas Stumbras

    Thread Starter New Member

    Jul 7, 2016
    14
    1
    will check how should it look ?
     
  7. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,542
    2,369
    If you are lucky enough, you will see two very small tabs sticking out of the primary winding with a wire connected to each, you may have to expose part of the coil bobbin to see it.
    Some are embedded deep, unfortunately it is a one-time fuse, it saves the transformer from burning out, but makes it useless in the process.
    Max.
     
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