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  • Yamaha EMX-2000 no power

    I am working on a Yamaha EMX-2000 that came in with a complaint of no power. Initial inspection showed the 7A fuse F103 was blown. I couldn't tell from the fuse markings or schematic if this is a fast or slow blow, but a search on another thread for this indicated it was a slow blow.

    I then started checking the heatsink mounted transistors and found Q117N (D2560) that has a short from collector to emitter. I pulled the board and found several other cracked solder joints on most of the heatsink mounted transistors. I'll reflow those.

    The emitter resistors R131, R132, R231, R232 test ok as does D118 (1N4004).

    To replace Q117N, are there any other components that I would need to replace to have things matched?

    Looks like B&D Enterprises has the 2SD2560 in stock as well as the complement 2SB1647.

    Thanks!
    Attached Files

  • #2
    The relevant part of the schematic is on page 33 of 69 in the lower right hand corner.

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    • #3
      Any suggestions for other components that may (should?) be replaced while I'm changing out Q117N (D2560)? I'd like to get my parts on order today, but want to make sure I don't miss ordering something.

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      • #4
        Considering it did not even take out the emitter resistor, I don't think there was much stress to the other components. It's a tough call but maybe the protection schemes did a good job and no other parts were stressed.
        I'm not familiar with the design enough to say whether the current in Q117 would have come through Q119 or Q123. But those are the main parts I would think may have also been stressed.
        Originally posted by Enzo
        I have a sign in my shop that says, "Never think up reasons not to check something."


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        • #5
          Thank you, g1! I'll be ordering parts later today.

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          • #6
            To wrap this up, replacing the fuse and Q117 was all that was needed. It's back up and running. Thank you!

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