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Hole in a transistor

Discussion in 'Troubleshooting and Repair' started by canactech, Aug 6, 2013.

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  1. canactech

    canactech

    38
    2
    Jul 7, 2009
    Hi, I have a problem with a RS-232 communication card that goes on an Epson TM-T88IV thrmal printer. There is a SOT-23 transistor with a hole in it so I cannot find the identification number. The circuit is identified as UB-SO1 model M111A, RS232 I/F BOARD, Parts 2116250, set 2116251. The transistor is supposed to be Q1. I need the model number of that transistor to be able to replace it by the same type.

    Thank you for your help.

    Canactech
     
  2. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

    4,960
    652
    May 8, 2012
    It's more than probable that something else failed which caused Q1 to pop like that. Do you know if the printer was hit by a mains spike?

    Posting clear photos of both sides of the board may help.

    Chris
     
  3. canactech

    canactech

    38
    2
    Jul 7, 2009
    The problem happens after a power cut.

    Thank you.

    Pierre
     
  4. canactech

    canactech

    38
    2
    Jul 7, 2009
    Concerning the photos, I've treid to do some but the circuit is very small and the camera that I,ve treid are not able to make a clear photo or you will see nothing because the image will be too small.

    Something that can maybe help you is that on the case of a transistor on another card there is two numbers: 14 print horizontally and 16 printed vertically. But it could be only production code so I don't know if it will be usefull.

    Thanks.

    Pierre
     
  5. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

    4,960
    652
    May 8, 2012
    Sorry but that doesn't help.

    Chris
     
  6. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,496
    2,837
    Jan 21, 2010
    There are a couple of things you can try.

    Firstly, if you can find a working printer, read the markings from a good transistor.

    Secondly, look at all the transistors on the board with the same package and see if there are only 1 or 2 types. If there are, then it *may* be one of these.

    Thirdly, post good pictures and see if we can work something out.

    when you say
    , do you mean "happened" or has this occurred multiple times?
     
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