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Behringer ufx1604 mixer repair (smpsu11)

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    Behringer ufx1604 mixer repair (smpsu11)

    Hello all.

    My first proper post to badcaps forum so just wanted to say a big thank you for all the information I've learned already from lurking and reading old threads.

    Signing up to the forum took a little longer than I'd expect so I've now fixed the initial problem I was having (and introduced a new one) but thought it would be good to document here and see if anyone has any ideas on the new problem.

    The initial problem was that when the mixer was turned on from cold, there would be a ticking from the power supply area and the mixer would continually restart.

    After removing power the power supply would continue to tick for another 30 seconds or so and then you could try again.

    I'd normally be able to get it on after 5 or 6 tries and tbh (naughty I know), once it was on I'd often just leave it on if I was going to be using it for consecutive days.

    This has gone on way longer than I'd like to admit now so decided to crack her open over the weekend and have a look at the power supply.

    It's a behringer smpsu11 power supply based around a NPC 200D6 IC.

    On visual inspection all electrolytics are 105' Decon's. (a brand I see gets no love on here)

    I first noticed a capacitor next to the transformer with obvious bulging at the top so that was my obvious first candidates.

    It was a Decon 63v 220uf shl which I replaced with a Panasonic EB 63v 220uf.

    While changing the cap I noticed a 2nd capacitor nearby also bulging and decided to replace all the electrolytics as a precautionary measure.

    I'd been reading some threads on here with people suggesting to use Panasonic FC in smps as they have a lower ESR than the EB's.

    Going on that I purchased FC replacements of the same voltage and capacitance for all the caps on the low voltage side.

    After removing all the Decon caps and testing them this is the result.

    V uf model ESR % out of spec
    35v 47uf sh - 15.85uf .14k 66.27%
    35v 47uf sh - 15.16uf .14k 67.74%
    25v 220uf slz - 177.2uf .43ohm 19.45%
    25v 220uf slz - 192.9uf .13ohn 12.31%
    63v 100uf sh - 88.90uf .56ohm 11.1%
    63v 100uf sh - damaged part (domed)
    63v 220uf shl - damaged part (domed)
    25v 1000uf shl - 909.5uf .00ohm 9.05%
    25v 1000uf shl - 905.0uf .00ohm 9.5%
    63v 100uf sh - damaged part (nothing visible)

    The mixer now turns on first time but I've noticed lots of noise coming out of channel 7 even with the gain turned right down. Sort of squelchy static that comes and goes at random.

    On the off chance that the Panasonic EB is causing the issue I'm going to change that out this morning and report back.

    Not sure how to get the attached photos in to here to label them but there are before and after shots and shots of the domed caps.
    Attached Files

    #2
    Re: Behringer ufx1604 mixer repair (smpsu11)

    the startup problem was probably one of the 47uf caps.

    Comment


      #3
      Re: Behringer ufx1604 mixer repair (smpsu11)

      The mixer now turns on first time but I've noticed lots of noise coming out of channel 7
      If the noise is only on one channel (channel 7) it won't be from the power supply, the power supply is common to all channels. Check the bad channel, and check for poor solder connections.
      Last edited by R_J; 06-28-2019, 09:43 AM.

      Comment


        #4
        Re: Behringer ufx1604 mixer repair (smpsu11)

        Originally posted by stj View Post
        the startup problem was probably one of the 47uf caps.
        Yeah, it didn't start after replacing the bulging dead ones but it did after the 47u's so I think you're bang on.

        Originally posted by R_J View Post
        If the noise is only on one channel (channel 7) it won't be from the power supply, the power supply is common to all channels. Check the bad channel, and check for poor solder connections.
        Cheers, I'll give that a look.

        My desoldering station isn't sucking properly at the moment and I was making a bit of a mess of trying to remove the EB from the power supply so I'll leave that in there and focus on the channel itself.

        It's all SMD components which is a bit tricker for me than through-hole.

        I did notice some residue on part of the back of channel 7 and 8. Not sure what that's from but worth focusing in on that area for a start I guess.

        Comment


          #5
          Re: Behringer ufx1604 mixer repair (smpsu11)

          On visual inspection the only thing that looks a little nasty compared to other channels is C268 but in circuit testing it seems to be fine. (see attached)

          I've tried connecting the input board with the inserts and input jack to different channels and the nasty sounds remain coming out of channel 7 so it does look like it's something in the channel strip.

          There are more decon electrolytics on the front of the board but they shouldn't have been subject to much heat.
          Attached Files

          Comment


            #6
            Re: Behringer ufx1604 mixer repair (smpsu11)

            scrub the board and deoxit controls and connections .

            Comment


              #7
              Re: Behringer ufx1604 mixer repair (smpsu11)

              Originally posted by petehall347 View Post
              scrub the board and deoxit controls and connections .
              I'll certainly give that a try.

              The only thing that's going through my mind though is that the channel was fine before the repair to the power supply and can't help but feel it may still be connected unless it's just a coincidence.

              Comment


                #8
                Re: Behringer ufx1604 mixer repair (smpsu11)

                Originally posted by retrop83 View Post
                I'll certainly give that a try.

                The only thing that's going through my mind though is that the channel was fine before the repair to the power supply and can't help but feel it may still be connected unless it's just a coincidence.
                FIRST! without doing anything. disconnect the ground from the AC PLUG.
                Majority of my humming in my mixer went away from disconnecting that stupid wire.
                The old British wiring design doesn't work with 2019.
                Some Old London houses are so bad, you have to demolish just to rewire the freaking cables.
                Just cook it! It's already broken.

                Comment


                  #9
                  Re: Behringer ufx1604 mixer repair (smpsu11)

                  Hi retrop83,
                  I exactly have the same issue with my UFX1604.
                  Crackles at channel 7 (and also channel 5).

                  Were you able to fix it finally?

                  Before thowing away the mixer I would give it a try to repair.
                  Any tipp is welcome if you have one ;-)

                  Kind regards,
                  Sawhead

                  Comment


                    #10
                    Re: Behringer ufx1604 mixer repair (smpsu11)

                    Hello I have this same source burned out so I would like to make an external source so I have doubts about the outputs I have already discovered that the red wire is 15V on the -15 side and on the other end the 2 are GND

                    Comment


                      #11
                      Re: Behringer ufx1604 mixer repair (smpsu11)

                      Did you find the proper voltages for the output of this PSU? Looking to verify mine is good or bad.

                      Comment

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