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  • Chroma Polaris, RIP

    I think my poor Polaris may have a fatal wound. I've been having trouble with one row of buttons on the left side of the panel up until recently. Now, ALL of the buttons are unresponsive. Sliders are fine. So, I thought it was due for a little TLC.

    Here's the beast on the bench, powered-up. Still plays, although I'm stuck with one patch and can't alter a lot of parameters due to the non-functional buttons.




    Inside, behold the glory of early 80's technology! (I screwed-up the img resize, sorry) Here the front panel is behind the main chassis, standing on it's rear edge.




    Here's the bottom view of the front panel. The controls are split between 2 boards, which are jumpered together via the colorfull loom you can see bridging them. The conventional ribbon cable carries all the control signals to the CPU board. Now, keep in mind that the Polaris uses those god-awful membrane-style buttons, can you see what the problem is? Take a close look.




    Let me point it out: The membrane switch ribon "cable" has gotten brittle and snapped in two. There are 4 of these ribbons, 2 that you can see here, and 2 more from the other board, which you might see between the two boards in the previous photo.



    Unfortunately, only one ribbon is still somewhat intact, the three others have all broken where the ribbon was bent to meet the board socket. The bends where not creases, but gentle bends. But, apparently the plastic was aging and they just broke under the stress.

    Here's the fatal problem:
    - The breaks leave no exposed conductive fingers to insert in the sockets. I tried gently scraping the green insulator off the bottom to expose the fingers, to no avail. Sandpaper didn't work either. The amount of scraping/sanding is either not enough to expose the conductor, or too much and the conductor is compromised as well.
    - With the ribbons now being shorter, there's no good way to get them back into the sockets, there's precious little slack left. I considered removing the sockets from the board and jumpering them with short leads to take the strain off the ribbons, but if I can't expose the ribbon conductors reliably, this is a futile exercise.

    I sincerely doubt anyone has Polaris front panel membranes lying around I could just replace them with. My alternatives:
    - Hold a wake and say goodbye, and then send it to the recycler
    - Find another busted Polaris to salvage and pray that its front panel hasn't suffered the same fate
    - Make a new front panel. Yes, I'm seriously considering this, if for no other reason than it'd be a cool, one-of-a-kind synth then.

    So: What say you, KSS? Bury it, fix it, or customize it?
    Hurrr. Derp, derp, derp.

  • #2
    It hurts to see this in pain. It's a cool synth. Well then....

    Why not

    Circuit bend it

    Did all the buttons work when you first got it?
    ____
    ______

    "It’s got to reflect a personality, rather than a quantized performance. Despite the technological revolution that’s been going on over the past few years, it’s not like we’re sitting around saying, ‘Wow... much better records are being made.’” - Atticus Ross


    Pumps from my Heart {+}{}{+}{} Filtered through my Mind ~-~->

    But yet I need more Cowbell



    if you never read my signature, you'll never know how I sign my name

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    • #3
      Do NOT circuit bend it, unless you have a death wish. Battery-powered stuff only.

      Comment


      • #4
        ...same thing happened to me a while back. Worked perfect until I opened it up to check the batteries. Closed it....and 2 rows of buttons were out. I sold it and bought an an A6. I love how the Polaris sounds though....super cool synth. I'd fix it...what the hell. I would have had mine fixed, but I had just spent $500 fixing my Chroma's power supply. Flippin' Chromas

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        • #5
          i have one. same thing. BOTH ribbons are out on mine.

          i found out that you can patch the solder points together on the back if you want to activate the buttons - use a wire of somekind, preferably while drunk so the sparks don't scare you too much.

          the way those ribbons are just epoxied in there doesn't leave much flexibilty for repair! if you figure something out, be sure to let me know.
          -jason

          youtube
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          • #6
            Have you searched for a replacement ribbon cable? I'm sure Fender sourced (not manufactured) them from somewhere, and who knows... maybe they're still available.

            Even if a replacement cable isn't available, why not just solder in some different connectors that use a cable that IS available?

            If you decide upon the "bury it" option, I'd really like to help. Just let me know, and I'll send you the cash to ship it to me. I'll do all the hard work with the uhh... shovel for a proper burial; I promise!
            Ski
            www.ex5tech.com

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            • #7
              the problem isn't really the cable, that could be sourced. the way the cable connects to the panel is the problem - it's literally sandwhiched in between plastic panels with epoxy, and i don't see a reliable way of getting it out.

              the connection to the actual PCB is a connector, thank god - but mine are broken _right at_ the membrane panel and there isn't a way to fix that without melting off the epoxy somehow.
              -jason

              youtube
              bandcamp
              soundcloud

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              • #8
                Sorry to hear your dilemma Pup.

                I found this page devoted to the Chroma. Has contact information for authurised repair techs & info on typical technical issues / schematics info etc:



                http://www.rhodeschroma.com/
                Vive La Synthesizer!

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                • #9
                  I recommend Good Guys Audio Repair in Minneapolis...they are certified Chroma repair techs.

                  Comment


                  • #10
                    Burn the plastic, metal conductor should remain intact, LOL. Seriously, that is just one wild idea from someone who knows nothing abouth fixing synths ;-)

                    Comment


                    • #11
                      Another vague idea... are there any solvents that'll take epoxy off?
                      Originally Posted by Metrosonus


                      working in a library I wish women would just come right out and say "where do you keep your soft core / torture porn at?"









                      Originally Posted by swardle


                      Well, I've never seen such filth in my entire life. Disgustation!!!



                      That's called pain. Get used to it.

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                      • #12
                        Burn the plastic, metal conductor should remain intact, LOL. Seriously, that is just one wild idea from someone who knows nothing abouth fixing synths ;-)


                        Don't know that I'd burn the plastic, but you're on the right track actually... Maybe look at rubbing the broken ends of the ribbon cable with acetone or something to expose a small (but large enough) area of the leads on each end of the broken ribbons. Just be sure to use small amounts of that acetone and work slow and careful. You don't want to slop it all over and potentially cause more problems. Maybe use a q-tip...

                        After that, find a way to connect the two broken ends...direct solder the 10 leads using new ribbon cable, put new socket "ends" on each of the broken sides and connect with a longer ribbon to give you more working room, etc. However you repair it, make sure that you keep all 10 leads separated so they don't short together. Poor man's solution - hot glue...solder them slightly spread apart, then dip the whole thing in the glue and let dry with them spread apart. Not the cleanest way, but if you aren't putting new socket ends on those ribbons that would be another way to go that would protect and insulate it electrically speaking.



                        If that doesn't work, have you tried an Xacto knife or scalpel to carefully cut between the leads and see if you can "peel" the plastic sandwich of the ribbon open leaving the leads exposed? Might be another way to go...


                        @scenic - unfortunately it sounds like you're screwed unless you could find a way to remove that epoxy and desolder the ribbon sockets. In your case, I'd really *not* suggest acetone

                        Thanks!
                        bax

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                        • #13
                          Thanks, everyone, for the sympathies and ideas!

                          I did a bit of Googling last night to see what else I can do. Apparently this is a common problem with the Polaris; The plastic ribbon just gets brittle and breaks. I saw another possible solution using conductive silver ink. If I can figure out how to expose the fingers on the ribbon that remains, I have an idea on how to make a good, permanent fix. I have acetone, I'll try a little of that.

                          Scenic: I think yours is screwed, bud. I believe the ribbon is actually an extension of the switch membrane itself, not a separate thing that's sandwiched between the membranes. It IS the membrane, it's one piece. Well, two, actually, the lower switch membrane and the upper switch membrane. If there's not enough ribbon left to work with....

                          I suppose that eh very least I could salvage the CEM chips and sell 'em. Or, if I REALLY had to keep it, stick the guts in a box and remote the controls via MIDI.... I dont' know if the MIDI is extensive enought o allow this though.

                          Poop. I hate broken equipement.
                          Hurrr. Derp, derp, derp.

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                          • #14
                            Scenic: I think yours is screwed, bud. I believe the ribbon is actually an extension of the switch membrane itself, not a separate thing that's sandwiched between the membranes. It IS the membrane, it's one piece. Well, two, actually, the lower switch membrane and the upper switch membrane. If there's not enough ribbon left to work with....


                            Now I understand. OMG, what an... "unfortunate" design. My sincere condolences.
                            Ski
                            www.ex5tech.com

                            Comment


                            • #15
                              Now I understand. OMG, what an... "unfortunate" design. My sincere condolences.


                              Yeah. Well, I'll be it was a lot less expensive for them to use that than to use discrete switches; There's 59 buttons on this panel. That would have added up in a hurry, not to mention the extra assembly time.
                              Hurrr. Derp, derp, derp.

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