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Help, trying to replace a transistor!

Discussion in 'Troubleshooting and Repair' started by Jordan gunn, Jul 13, 2017.

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  1. Jordan gunn

    Jordan gunn

    1
    0
    Jul 13, 2017
    IMG_8014.JPG Hello I'm trying to locate the transistor in my radio I watched a YouTube video where a guy repaired a very similar radio by replacing its transistor and claimed it was a common problem for this model. I have bought a 2n2222 transistor to replace it with but the layout in the video is slightly different than mine and I can't locate the transistor to replace it. Anyone know which one it is?
     
  2. davenn

    davenn Moderator

    13,580
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    Sep 5, 2009
    what is the problem ?
    and what is the link to the video ?

    we have no idea till you give a bit more info
     
  3. 73's de Edd

    73's de Edd

    2,870
    1,216
    Aug 21, 2015
    Sir Jordan gunn . . . . .

    Need brand and model # of your unit.

    Describe your units problem . . . dead? . . .distorted sound . . .very weak sound . . . .picks up few stations.

    The one thing that you DO have going for you is the fact . . . . that unit is amongst the last of the pocket transistors and is using silicon transistors in the form of those black topped Fairchild units in your set . . .AND . . . a 2N2222 works/subs for a whole bunch of transistors.

    73's de Edd
     
  4. ramussons

    ramussons

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    Jun 10, 2014
    The transistors have been located.
    . Transistor.JPG
     
  5. Minder

    Minder

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    Apr 24, 2015
    It looks like an old one,Hopefully not the germanium transistor kind, usually there is a number on the transistor
    With those many times the problem semi can be identified using a can of cold spray/Arctic Air which can bring them back to life momentarily.
    This is IF it is a semi problem.
    Two or three of them will be RF type transistors.
    M.
     
  6. duke37

    duke37

    5,360
    765
    Jan 9, 2011
    Measure the voltages on the transistors. Silicon transistors will have about 0.6V between base and emitter. The collector will be more positive than either with an npn transistor. Measure voltages relative to 'chassis' which with npn transistors will be connected to the battery negative.
    The emitter voltage can indicate if the transistor is passing current.
     
  7. kellys_eye

    kellys_eye

    4,276
    1,146
    Jun 25, 2010
    Hold the radio close to another radio operating on the same band.

    By varying the tuning of one of them you will hear a 'whistle' (called heterodyning) that will indicate the local oscillator is working correctly.

    If you CAN'T get this whistle then the transistor closest to the RED tuning coil will be the dud one.
     
  8. ramussons

    ramussons

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    Jun 10, 2014
    How about a link to the original YouTube video? Maybe we can guess which transistor was replaced.
     
  9. 73's de Edd

    73's de Edd

    2,870
    1,216
    Aug 21, 2015
    Sir . . . . Jordan Gunn . . . . . . . . . . . . . . . ( Not ? ? ? THE . . .famous Jo Jo Gunn ! ? )

    ( http://www.theworldaccordingtorandy.com/files/Beatles - Get Back.mp3 )

    Ya’ know what ? . . .we thinks that maybe that you forgot to give the ALL IMPORTANT Brand and its Model number.

    ALSO hook a battery up and put your ear against the speaker. Turn on to see if you hear any initial “ plop “ noise at turn on, from the speaker.

    At turn on, run the volume control up and down, rapidly, to see if there is any “ staticy “ noise on its movement, being heard from the speaker ?

    Any semblance of reception when you leave the volume at max and tune across the AM band . . .. from end to end ?

    System Identifiers:

    [​IMG]


    73’s de Edd
     
    Last edited by a moderator: Jul 14, 2017
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