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Roland jupiter 6 repair

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  • Roland jupiter 6 repair

    Hi folks!
    Im with this roland jupiter 6 on the bench, so far so good, then I get stuck trying to toubleshoot this issue. Aparently I have two voices missing. Looking at the waveform outputs of the CEM3340 chips I have two with no output at all. First I suspect the CEM chips, or the 4053 CMOS next to them. so I desoldered all of them and put sockets to swap them out. The two CEMs with no waveforms at the outputs are working properly in other positions, so they are not the issue aparently. then I swap IC34A (EHM-S226W83S) and IC41A (BA662), nothing changed still no output on that VCOs
    Some idea??

    jp6-page12.pdf

  • #2
    Look at the control voltages coming into the voice, compare to those of a working voice. Any open R-packs?

    The VCOs are controlled by the envelopes, a voice set to take a couple minutes to bring up sound, for example, will sound dead.
    Education is what you're left with after you have forgotten what you have learned.

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    • #3
      Originally posted by Enzo View Post
      Look at the control voltages coming into the voice, compare to those of a working voice. Any open R-packs?

      The VCOs are controlled by the envelopes, a voice set to take a couple minutes to bring up sound, for example, will sound dead.
      Thanks Enzo, Im getting mad with this sh*#$
      this is my DC measurements comparision,

      PIN# // working VCO

      1 = -1.97V
      2 = -4.39V
      3 = -5.16
      4 = -5.36V
      5 = 1.62V
      6 = -2.59V
      7 = 18mV
      8 = 3.33V
      9 = 3.33V
      10 = 1.66V
      11 = 3.41V
      12 = 0V
      13 = 0V
      14 = 20mV
      15 = 0V
      16 = 10V


      PIN# // VCOA1 (no output waveform)


      1 = -1.98V
      2 = -4.38V
      3 = -4.99V
      4 = -9.2V
      5 = 1.63V
      6 = -2.57V
      7 = 28mV
      8 = 1.22V
      9 =3.35V
      10 =-1.21
      11 =296mV
      12 = 0V
      13 = 0V
      14 = 12mV
      15 = 0V
      16 = 10V


      PIN# // VCOA2


      1= -1.9V
      2 = -4.3V
      3 = -5V
      4 = oscillating from 0V to 9V
      5 = oscillating from 1.5V to 1.6V
      6 = -2.56
      7 = 37mV
      8 = oscillating from 0V to 6V
      9 = 3.40V
      10 = oscillating from 0 to 3V
      11 = 1V
      12 = 0V
      13 = 0V
      14 = 232mV
      15 = -444mV
      16 = 10V





      already tested the R packs and they are ok. also I have swapped the S2W83S and the 4053īs and replace IC20 4051 with no luck
      Last edited by angelothewolf; 05-23-2018, 06:53 PM.

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      • #4
        bumping an old thread because I have exactly the same issue right now on my MKS-80 (the rack nephew of the jupiter 6). also pin 10 of the cem3340 is -1.2 volts instead of 1.66.
        Swapping the 3340's doesn't make any difference. sometimes the vco comes back to life, but only when the unit is still cold. (so maybe temperature related /faulty component).

        still searching for the cause. did you have any luck finding it Angelothewolf? or maybe someone else has a suggestion?

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        • #5
          Found it! the culprit was a failing polyester cap, (c94 in the MKS-80) the one between pin 11 and pin 12(gnd) on the cem3340.

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          • #6
            Hi just jumping in as similar topic…I am after a Roland S2W83S also called S226W83S… I am having difficulty sourcing…the rest of my J6 is going really well. Thanks if anyone can help.
            Andrew

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