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MXR M87 comp going wacky

Discussion in 'Effects [BG]' started by scottfeldstein, Mar 22, 2014.

  1. So for the last few days I've noticed that when I power on my board, my MXR M87 compressor does some weird stuff.

    First, the metering LEDs all light up. Even with nothing going into it. And it just stays like that. All lit up. And when I put a signal through it, nothing comes out. I can pull the power, fiddle with knobs, it just stays maxed out, redlined. And nothing coming out.

    So I leave it powered on, but bypassed. Sound flows. And after about 5 minutes it starts to come down. The metering LEDs start to shut off bit by bit. And then it seems to start acting normally. Except I find I have to readjust the input/output knobs to achieve anything like similar volume to my bypassed signal. But after a few minutes this returns to normal, too.

    Then it's fine.

    What's up? It's second in my pedal chain, right after my tuner (which seems totally normal). It's all powered by a one-spot, same power supply and same pedals I've had for quite some time now.

    Anyone else seen this behavior? Should I contact Dunlop?
  2. bongomania

    bongomania Gold Supporting Member Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    Yes, contact Dunlop.

    They seriously need to sort out all the glitchy and faulty M87's, and fgure out what 's going on with the production.
  3. When I power up my board, all the LEDs light up for a few seconds and then it goes dark. Other than that it seems to work fine. I just thought it was an idiosyncrasy of that model. Hope nothing else goes wrong as I got a mail saying that the warranty had run out a few days ago.
  4. alec


    Feb 13, 2000
    Perth, Australia
    Scott, the same thing happened to mine. MXR fixed it but it took two trips to the shop. Here's how I described it to them:
    When it is powered, all of the metering lights come on and stay on.
    In bypass, the pedal works (though the metering lights stay lit) but when
    engaged, the signal is so low that I have to turn the input and output right up in order to hear anything. When I disconnect the power, the lights fade out in a strange but consistent pattern.
    If I leave the pedal on, the output level slowly increases as the metering lights fade out. It takes about five minutes for all the lights to go out and I'm at unity gain, but no compression seems to be taking place (visually or audibly). Changing the ratio doesn't cause the lights to peak like they normally would.

    If I cut the power, the lights still flicker in the same pattern. Restoring the power causes the meter to light up and fade out right to left over about three seconds, like it used to. But still no compression.

    And when it came back the first time it was a little different:
    The maxxed-out gain reduction still happens, usually when one (any) of the knobs are turned, sometimes when the footswitch is clicked.

    Sometimes the gain reduction fades away after ~10 seconds, sometimes five minutes and sometimes it never gets below the last four lights.

    The second time it came back it was OK.
  5. Hey, how long have you guys owned your pedals?
  6. bongomania

    bongomania Gold Supporting Member Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    I've had mine for two and a half years.

    FWIW, it is normal and non-problematic that the meters all light up and stay lit up for a couple of seconds. If they stay lit up for anything longer than, say, five seconds or so, then I think that's a sign of something going wrong.
  7. Good to know. I guess mine's working fine then.
  8. I got mine in August of 2011. It's been perfect under pretty light use up until the last couple of weeks.

    I think I'll give 'em a call on Monday. I'd hate to gig without it. Listening to myself in a stage mix without it feels like I have all my clothes on backward. Just not right.
  9. I talked to Dunlop yesterday afternoon. They suggested that I open it up and make sure the battery contacts weren't shorting on the housing or something. So this morning I opened it up. It didn't look like it was touching anything, but I covered it with electrical tape anyway. When I fired it up again, it did the exact same thing.

    Fortunately, they said I could send it in, so I think I'll give 'em a call back today and arrange that.

    Sad. I haven't had a gig all winter, now I'm going to do my first one this year without compy. :crying:
  10. GretschBassist


    Nov 11, 2012
    2,5 years of constant use is a good life span for a pedal made of the given components. It might just be time to get a new one. I recommend the Markbass Compressore. The next logical step in compression ;-)
  11. I don't see it that way at all. I expect that it's going to last five or ten years, especially since it sees very light use. It's probably been powered on for no more than three or four hours a week for the entire time I've owned it. That's 520 hours of service. I have light bulbs in the studio that have been in use for longer than that.

    Anyway. I get that it's out of warranty. I'll be pleased if Dunlop fixes or replaces it on their own dime. I get that they don't have to. And if I have to suck it up and buy a new one, I will. But I wouldn't buy the same model, no matter how pleased I was with it while it worked. Once bitten, twice shy. It's proven unreliable.
  12. mmbongo

    mmbongo Chicken Pot Pie. My three favorite things!! Supporting Member

    Dang. Scratching this one off my list for sure. I've never kept an MXR pedal for more than a week anyway.
  13. silky smoove

    silky smoove

    May 19, 2004
    Seattle, WA

    That's exactly how mine behaves. All meter LEDs come on when power is applied to my board, and after about a second they go dark. After that "boot up" it functions perfectly, and sounds great.
  14. I should add that their tech support folks are being extremely cool about all this. They've given me a return authorization number so I can send it in.

    Now that I've started this thread I feel compelled to update it to conclusion, so stay tuned!