Vintage Synth Repair

I'd prefer not to mention that, because an LED was bad on it - but - I fixed it.  A reputable source, from other things purchased from them.  Since I mentioned that to them, I told them I wouldn't pass on bad info.  I may need a favor down the road.

I think I need to scour the sucker thoroughly one more time for any trace problems.  I'm thinking it's on the top left mommy board but there are 2 others in there as well.  Sounds like a complete breakdown of the synth and complete look over.  If it's a chip gone bad, I may SOL, but maybe not.

BTW, it IS better than it was, but not up to speed.  So, the replacement board did help it some so far.

Tracy


--------------------------------------------
On Wed, 5/2/18, plat@... [vintagesynthrepair] <vintagesynthrepair@yahoogroups.com> wrote:

 Subject: Re: [vintagesynthrepair] Help With a Chroma Polaris - Please?
 To: vintagesynthrepair@yahoogroups.com
 Date: Wednesday, May 2, 2018, 6:15 PM


  



   





       Hi, where did you buy the replacement panel ?



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 Frá: "vintagesynthrepair"
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 Til: "vintagesynthrepair"
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 Sent: Mánudagur, 30. Apríl, 2018 05:03:12

 Efni: [vintagesynthrepair] Help With a Chroma Polaris -
 Please?



 Hi Everyone -



 I have just undertaken refurbishing my Polaris.  I fixed the
 output jacks, did a mod on my headphones (absolutely NO
 NOISE!), replaced the entire faceplate (Paul DeRocco)
 (because of faulty original strips), soldered in an LED and
 swapped out two sliders after repairing and cleaning
 them.



 To me, that's about 4 hours work..  But I love my Polaris
 sound.  I wouldn't do all that for another keyboard,
 except for...   anyway, here's my woes...



 1) Filter Cutoff.  when you first start to slide, it's
 sort of dead but then comes to life.  Slide back to bottom
 and the sound completely goes away.  Dead space.  It's
 not the slider because I just changed it and received the
 same results as before.  Exactly the same, but better
 movement.



 2) Resonance - next to the Cutoff - related problem?  I just
 replaced the slider and received the same results, although
 the slider was cleaned and so forth.  When I hit the top, it
 gives resonance, but also some when I pull it all the way
 down.  Ridiculous.  Also much better movement.





 3) I replaced the top left motherboard a while back with a
 used one (hence the broken LED) but that works now over
 Noise.  Minor issue, can't complain.  I had similar
 problems before with the old top left motherboard, but the
 sliders were a little bent and gave a slightly different
 result.  This tells me it goes deeper than surface.



 4) Now - when these problems occur, hitting the patch number
 I was playing brings back the original patch with no
 deformities / abnormalities.  That's nice, but when I
 want a little Cutoff, I get totally "cut off" (pun
 intended).



 5) The sliders on Cutoff and Resonance and smooth with no
 bumps / bruises since they'd been cleaned / replaced.
 At least I'm learning some good techniques here.
 There's a guy on YouTube who demonstrated how to do it
 properly and I think I have that part down now.



 Observation: Methinks the Cutoff and Resonance have a chip /
 board problem but I wouldn't know where to look.
 I'm getting handy with a soldering gun, but not with
 schematics.  I have 25 years repairing PCs but little
 multi-meter experience, especially when the specs aren't
 available.  I have the Polaris schematics and service manual
 but I need to research it to get a clue as to what I'm
 up against.



 If anyone can help me here, I have the remainder of the old
 top left motherboard, minus a few sliders and an LED that
 I'd gladly send to you in exchange for the info.  The
 sliders sell on eBay for a few $ and it would be a small
 gold mine of parts.



 Thanks for reading.  I hope to hear from someone on this -
 even a clue!



 Tracy Barber

  Polaris Fiend











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