Luxman M-02 Power Amp BBQ

Discussion in 'Solid State' started by madtech, Oct 28, 2018.

  1. madtech

    madtech AK Subscriber Subscriber

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    700
    Location:
    New Brunswick
    This one has been under my bench for years and I've finally found the time to have a look. Seems like the previous owner blew the 1302/3281outputs on the right side and attempted to replace them with some "high quality" replacements. Previous stage was also BBQ'd. When they installed the replacements they didn't bother cleaning up all the carbon. Luckily it wouldn't come out of protection with all the NTE junk in there and nothing else fried. Bought some OnSemi replacements for the outputs. Capacitor C110 is listed as 1000pf but has no listed voltage in the shop manual. It's hooked up between the base and collector so I'm thinking 100V should do it?
    Copper side is a bit of a mess but repairable. Heat sink for the outputs looks like something from Star Wars.
    Looking forward to getting this running again after the abuse it's been put through. I've re-capped the C-02 pre-amp and it's ready to go.

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    Last edited: Oct 28, 2018
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  2. slimecity

    slimecity Super Member

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    Your pics arent showing up.....
     
  3. Blue Shadow

    Blue Shadow Waiting for Vintage Gear from this century Subscriber

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    Well if the C-02 is ready to go the M-02 should be next. Good Luck. I'll check back to have a look at the pics when they show up.
     
  4. madtech

    madtech AK Subscriber Subscriber

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    If you look close, you can see where they soldered two resistors in series to come up with the desired value....... :)
     
  5. Blue Shadow

    Blue Shadow Waiting for Vintage Gear from this century Subscriber

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    When I was repairing crisp circuit boards in the MB3045 amp, I was told that the char can be somewhat conductive. I removed it completely and rebuilt the board with epoxy and some board shavings for color. Works a treat and the amps sound wonderful. I don't think Luxman had heat transfer engineers, just co-op students doing that part of their design. But boy their units sound nice.

    Heat pipes became common in the early 80s. must be horizontal so the liquid flows to the heat source, evaporates and flows to the sink area to condense. A lot less metal needed for these than the regular finned sinks we see all the time. They must work just fine, lots of companies used them.
     
  6. lico

    lico AK Subscriber Subscriber

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    Now this is a thread I like to read instead of the usual "what caps should I get" for a recap. Make it sing!
     
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  7. wmgwizard

    wmgwizard Super Member

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    I miss my C-02/M-02 combo every day, one of those things I should have never let go.

    Good luck with your repairs, hope it all works out for you.
     
  8. ryuuoh

    ryuuoh FFXIV Summoner Subscriber

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  9. madtech

    madtech AK Subscriber Subscriber

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    Yes, I suppose that's something else that I should look at. I don't need anymore components turned to charcoal.....
     
  10. madtech

    madtech AK Subscriber Subscriber

    Messages:
    700
    Location:
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    Re-cap is complete. Have to re-flow the entire main board. Almost every 1 in 3 solder joints needs to be redone.

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  11. madtech

    madtech AK Subscriber Subscriber

    Messages:
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    Location:
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    Solder re-flow is all done. Schematic shows in red what was blown. I'm debating pulling all the remaining transistors or taking my chances with my dim bulb tester......Nothing to the left of the red line has been tested.
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  12. Nightwisher

    Nightwisher Farer In The Goldilocks Zone Subscriber

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    Good to see you getting this up and running! My C-02/M-02 combo is my daily driver.
     
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  13. madtech

    madtech AK Subscriber Subscriber

    Messages:
    700
    Location:
    New Brunswick
    Just noticed the output emitter resistors (.22 ohm\ 5W) are from 4 different manufacturers. At least they were the same color. Yet another Mouser order......
     
  14. madtech

    madtech AK Subscriber Subscriber

    Messages:
    700
    Location:
    New Brunswick
    The new outputs are installed. Dim bulb test went fine so it looks like there are no shorts. Flipped to main power and it won't come out of protection......bummer. The red LED D102b on the right channel won't light up, so it looks like I have an issue earlier in the stage. At least there is no smoke!
     
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  15. FootFungus

    FootFungus Super Member

    Messages:
    1,118
    Location:
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    I've got a M-02 that's toasted in the exact same place - completely roasted through the board though.

    There are a lot of fusible resistors that can fail, so check those if you haven't already. Nice work so far.
     

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