Retro-fit keyboards for analogue synths (theoretical rant)...
Old 13th September 2013
  #1
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Retro-fit keyboards for analogue synths (theoretical rant)...

A couple of days ago I had to open up my Octave CAT as the keyboard was starting to jitter the pitch. Decided to take the whole thing apart and clean out all the sliders, pots and switches (isopropyl, and Kontakt 701) before calibrating - BTW its a practise I'd highly recommend once in a while to remove any dust that gets in there.

The one thing that annoys me about the CAT is that damn j-wire keyboard. Got a few j-wire synths, and never had that much problem, but because of the CAT's duophonic mechanism it has two bus bars to dictate when two notes are being held down. To my annoyance I have to tip the unit at an angle, delicately move the wire so that the (hope I'm right on this) upper bus bar has a contact before the bottom... only to find that when I move the unit back in position, gravity usually gets its ugly way and causes the j-wires on one or two notes to move out of place slightly.

Anyway, just been thinking about this over coffee... surely in today's world there should exist a company that does modern retro-fit keyboard mechanisms... I know I know, it would be very (very very!) niche, and each analogue synth has its own different way of dealing with the bus bar - just thinking how cool it would be if somehow all of these mechanisms could be upgraded to something a bit more standardised. This is a very casual topic by the way, so don't hate... just theorising!
Old 13th September 2013
  #2
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ionian's Avatar
I wish. You and me, both. I have an Oberheim OB8 and the keyboard is giving me a lot of problems with oxidized contacts. Some of the bushings went bad so certain keys are clacking and not sitting right.

It's a more modern membrane type keyboard that's used in tons of controllers today. I wish I could just buy a drop in replacement - seriously. I'd buy one in a second. There's just a ribbon cable connecting it anyway, it wouldn't be hard to replace. I'd even buy a controller to rip out the keyboard if I could find one that worked or fit!

I agree with you - in this day and age there should be someone making drop in replacement keyboards. It's got to be one of the easiest things to replace.

Regards,
Frank
Old 13th September 2013
  #3
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Yoozer's Avatar
But what if an octave of keys subtly differs in width? Fatar's not going to make a dozen versions. Padding excess space at the right endcheek is not that much of a problem, extending a case, however...

What you want is Optokey for every keyboard out there; just take contacts out of the equation completely and leave that job to a set of scanners, then leave it to the software/outputs to generate either CV directly (Minimoog) or send the right multiplexed signal to the CPU.

Yes, the keys will still suck, but at least you won't be depending on thin wires to do the job; as long as the springs work, everything should be A-OK.
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Old 13th September 2013
  #4
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or use the method from the Polivoks -- magnets glued in the undersides of the keys and reed switches at the base. Press a key, the magnet gets close and activates the reed switch indicating closure. Nothing to oxidize or break. A very nice solution.
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Old 13th September 2013
  #5
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OK I'm going to be cheeky. It I was in that situation where the original keyboard was truely knackerd, I'd buy a few appropriate keyboards off ebay (cheaply) then see how the keyboard worked and adapt it. If it was digital I'd be looking at Kenton to see what they had, then possibly use a Ardunio kit to convert the orginal signals into something to suit. These Ardunio kits are easy, just requires a little bravery and time.

Some hints: A Hammond C3 keyboard can't be adapted , Ensoniq AfterTouch keyboards (I think Fatar) use aftertouch and use some wizzy electronics, could be tricky.
However I would think any synth using that standard Fatar style might be worth a look.
Old 13th September 2013
  #6
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Quote:
But what if an octave of keys subtly differs in width?
Yeah that's the major drawback... different case configurations, varied key sizes etc. Its not an elegant solution as a dozen templates for key molds would have to be created, then housed in a frame - expensive. So the better option would be to have a circuit board that handles the keyboard tracking with an existing chassis/key-bed.

Quote:
What you want is Optokey for every keyboard out there.
Now THAT is something I wasn't aware of! Looking at the Moog model D retrofit it seems to be a really nice solution. I wonder if Kevin Lightner has considered doing variations of the circuit for different synths? Essentially the only modification is with the scanner, board mounts and circuit i/o?
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Old 13th September 2013
  #7
Gear maniac
 

I thought I saw someone offering drop-in replacement keyboards for vintage synths a few years ago. I've done a search and can't find anything now though.

I like the idea of the Opto-Key because it keeps the look and feel of the synth original. I had trouble with my Minimoog's contacts when I got it, but found that a new set of keyboard bushings had been installed upside down. It has played fine since it was corrected, so no desperate need for me to change the contacts. The bi-directional MIDI might temp me though.

Most of my vintage synths have a Pratt & Read keybed although they all do seem to have different circuits/connections attached to them, so a standard drop-in plug-in replacement for multiple models certainly might not be possible / cost effective. An Opto-Key style replacement however, designed for specific models, sounds like a very good idea.
Old 14th September 2013
  #8
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Silver conductive grease to fix intermittent J-wire contacts.

I did my E1 and P5 about 5 years ago.. Still work flawlessly.
Old 26th January 2014
  #9
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adhmzaiusz's Avatar
 

Quote:
Originally Posted by Futureman84 View Post
Silver conductive grease to fix intermittent J-wire contacts.

I did my E1 and P5 about 5 years ago.. Still work flawlessly.
I am so happy to have discovered this thread specifically for this little bit of advice.

I've been in the process of restoring 3 octave cats, only one of which worked alright (it's gone now, 2 more to go). The most fidgety and annoying thing are the j-wires, they are practically impossible to refurbish...until I tried silver grease. Unbelievably it works like new, I even got my minimoog working 100% by putting a touch of this stuff in there. For years now I've been fussing with all my j-wire synths and tried everything, but this stuff is the solution. Thank you thank you thank you.
Old 18th December 2014
  #10
Gear interested
 

Is silver conductive grease the same as a thermal paste, like this one?

Or should I rather go with something like this?

Quote:
Originally Posted by adhmzaiusz View Post
I am so happy to have discovered this thread specifically for this little bit of advice.

I've been in the process of restoring 3 octave cats, only one of which worked alright (it's gone now, 2 more to go). The most fidgety and annoying thing are the j-wires, they are practically impossible to refurbish...until I tried silver grease. Unbelievably it works like new, I even got my minimoog working 100% by putting a touch of this stuff in there. For years now I've been fussing with all my j-wire synths and tried everything, but this stuff is the solution. Thank you thank you thank you.
Old 18th December 2014
  #11
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Quote:
Originally Posted by ZX81 View Post
Is silver conductive grease the same as a thermal paste, like this one?

Or should I rather go with something like this?
It is a different product I think, but that might be the same! This is what i used:
Silver Conductive Grease | MG Chemicals

Should be able to find it at any specialty electronic components retailer
Old 18th December 2014
  #12
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Quote:
Originally Posted by ZX81 View Post
Is silver conductive grease the same as a thermal paste, like this one?

Or should I rather go with something like this?
I don't think you want CPU heat sink paste. It's made for non-moving parts and that makes me think that is could be very thick and sticky. The silver conductive grease, MG 8463, looks like the right stuff. I actually bought some silver conductive grease a couple of years ago for my Odyssey j-wires. I should find it and let you know exactly which brand and model number it was.
Old 19th December 2014
  #13
Gear interested
 

Thanks a lot guys! I should have read the description more closely.
Old 4th March 2015
  #14
Gear interested
 

Hi fellas
Where do you apply the grease
I have a multimoog with jwire contact issues and was hoping to use this method to radicate the problem
Thanks
Old 4th March 2015
  #15
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Where the J wire touches the bus bar.
(Underneath the key bed - look there .. Press a key.. See the tiny wire make contact with the thicker bus bar? At that intersection put a tiny tiny bit of silver grease)
Old 5th March 2015
  #16
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Is there any serious soldering required for the Opti-Key install?
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