Home › Forums › Help/Technical Questions › LPB-2 not boosting — any ideas?

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  • November 3, 2010 at 1:09 am #80940
    devnulljp
    Participant

    My old LPB-2 is no longer boosting — it’s at unity volume when cranked.
    Mine’s the old PTP wired version, so no board, just a bunch of components wired together. No electolytics to have dried out.Any ideas where to start looking for faults? I don’t see anything obvious…

    c3b53f9b.jpg
    444eef20.jpg
    818f9250.jpg
    efd9d0c6.jpg
    636de852.jpg

    November 3, 2010 at 2:10 am #112350
    The EH Man
    Moderator

    I would guess either the battery or the transistor.

    November 3, 2010 at 2:30 am #112351
    devnulljp
    Participant

    Battery’s good — I tried a few and a 9V adapter via a clip.
    Can I test the transistor? (How?)
    Thanks

    November 3, 2010 at 9:47 am #112357
    The EH Man
    Moderator

    Can you measure the voltages on the leads?

    November 4, 2010 at 12:35 am #112373
    ranjam
    Member

    You’ve added true bypass switching, but did you do anything else? It looks like you have the collector on the ‘left’ lead of the transistor, and I’m not sure I’ve seen many transistors that do this. It would appear the pin configuration you have is c-b-e, and it’s usually e-b-c. Everything else looks OK, unless the switch is wired wrong.
    Does your transistor say 2N5058? It’s difficult for me to read that, but any 5058 I’ve seen is a TO-39 or soup can.

    November 4, 2010 at 2:52 am #112376
    The EH Man
    Moderator

    It’s likely a 2N5088.

    November 4, 2010 at 3:03 am #112377
    devnulljp
    Participant

    It’s a 2N5088
    Config is
    2N5088-pinout.jpg
    2N5088-circuits.jpg

    Does it need to be flipped around?

    EDIT: flipped the transistor around — BOOST!
    dohd.jpg
    Thanks

    November 5, 2010 at 1:01 am #112392
    ranjam
    Member

    I’m surprised I saw that. Yet I did, and it is a typical e-b-c small signal transistor. I’m glad it all worked out.

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