Electrical Adjustments for D-15?

Discussion in 'Discmans, Minidisc, DCC and other players' started by nev4eh8959, May 1, 2020.

  1. nev4eh8959

    nev4eh8959 Member

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    I have a feeling I just discovered a new all-time favorite !

    Oh by that I mean my AC-930A, the one that I opened.

    Thank you for your help! I'll check Q409/Q434! And you mentioned that you had bad Q409/Q434, what symptoms did you have before replacing them?
    Thanks again!!
     
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  2. Jorge

    Jorge Well-Known Member

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    Mine was cold-dead. It did not help that previous owner tried to fix it by randomly poking soldering iron into the board. Since there is no consistent way for how transistors fail, it does not actually matter. Reflow Q409/434 then measure voltages, check where heat is originating. If D-15 flickers On and Off then put it in Service Mode.
    Using desktop power supply (like this one: 15V 2A Adjustable DC Power Supply, you cannot beat $12.55 with free shipping!) shows how much current Discman draws, may save you some troubles if there is an intermittent short somewhere.
     
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  3. nev4eh8959

    nev4eh8959 Member

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    Hello!
    I made some progress on my repair recently!
    I checked Q409 and Q434, the input and output of them are 8.93V and 8.92V. These values in the manual are 8.6 and 7.4. Does this mean they are dead?
    what should I use as replacements if they're dead?

    Update:
    I checked its base emitter voltage and got around 400mv(I didn't desolder them).


    Thanks a lot !
     
    Last edited: Jul 11, 2020

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