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Poly800 sometimes suffers from, verry low output volume / noisey output / only sound from right(left) output

Poly800 sometimes suffers from, verry low output volume / noisey output / only sound from right(left) output

2015-01-28 by berendnie@...

Hello everybody! I will try to be as brief as possible!


My Poly800 sometimes suffers from a verry low output volume and or a noisey output and or only sound from the right(or left,) output/headphone channel.


Is there a good chanse it could possible be the on off and volume potentialmeter with on/off switch? ;)


It looks like a stereo pot with a on and off switch. Any id what replacements to look for?


Sometimes when i put it on, the sound looks/sounds like it slowly disapears.. from a normal volume to a verry low volume, about 5% of what it should be.


This behaviour is pritty wierd for just a dirty potentialmeter isue, what do you think?


Other times it happens after changing volume..


Also i had some instand verry noisey output ((sounds like the normal sounds but realy distorted)) after switching the program/sequencer enable disable switches on the back, but I think this is just random.


The unit looks pretty neet on the inside.. no battery damage or corotion from water damage or etc.. only dust and cat hair!


Could i be on the right track? or?


THanks for reading!



Re: [korgpolyex] Re: Poly800 sometimes suffers from, verry low output volume / noisey output / only sound from right(left) output

2015-01-28 by Louis Botterill

if you've not already, you could try switch cleaner and checking around the pot for dry solder joints. I've just resurrected a 32 year old Sequential MAX where the volume was all erratic and noise would appear randomly. Working some switch cleaner in for a while fully fixed it, like new now. No new pot needed. Also fixed the rotary encoder on a JD-990 in the same way, even though it was completely dead and I thought it was a goner.

Re: Poly800 sometimes suffers from, verry low output volume / noisey output / only sound from right(left) output

2015-01-29 by berendnie@...

HI Louis,

Thank you, are you talking about deoxit? any type you can suggest ?

It also makes crackling noises when turning the pot so i think the problem is just dirt.. but i will look at the solder joints to be sure.

I also had a dirty pot in my prophet 2000, which made is unprogrammable..

I know a good way for cleaning pots is to open them up, big chance you did the same with the JD-990 encoder. I dont want to open this one up;), to complex and delicate pot.) maybe its a good id to just let it soak in switch cleaner solution/deoxit, what do you think?

I've been looking for a sci max for some time, hoping to find one cheaper than a sixtrak!.. good stuff!

Re: [korgpolyex] Re: Poly800 sometimes suffers from, verry low output volume / noisey output / only sound from right(left) output

2015-01-29 by Louis Botterill

Well not sure where you are and what you can easily get hold of.

I've been using Servisol Super 10 which is like a de-facto switch cleaner and it works wonders. Really permeating too. You might need to spray a couple of times and work it in a bit, but if the pot is cracking it's surely going to help a lot, if not fix it completely.

I had to strip the JD990 down, but interestingly the decoder pot I was able to fix without taking it fully apart (it appeared pretty sealed, so that was a relief). The cleaner really permeates in through any small gaps. Just wind the wiper up and down a lot and spray it several times until comes good. I mean perhaps if it's really shot you'll still have to replace it, but 9/10 it's just dirt and tarnish and the cleaner should sort that out quite effectively. Sometimes pots also get dry joints around them, so that's the second guess. But cleaning would be my first step.

The MAX is a real gem it turns out. Has a really complete midi spec for a true analog synth. I've just done the Tauntek RAM/ROM upgrade on it and that's really improved it further, making it more usable. Also got 6 VCO unison mode now, as well as the existing 6 VCO multi-timberal modes. Also now stores all six-track and multi-track in the ROM, as well as 100 non-volatile user patch memory (and extended sequencer size).

They don't seem to appear that often, but if I see one cheap I might get another, got another project idea for one now. This one I've just modded I've had for years but never used that much due to original limitations, now it's back in the game. Like the Poly800 hopefully will be once modified too.

Good luck. 

All the best, Louis



On 29 January 2015 at 14:41, berendnie@... [korgpolyex] <korgpolyex@yahoogroups.com> wrote:
 

HI Louis,


Thank you, are you talking about deoxit? any type you can suggest ?

It also makes crackling noises when turning the pot so i think the problem is just dirt.. but i will look at the solder joints to be sure.

I also had a dirty pot in my prophet 2000, which made is unprogrammable..

I know a good way for cleaning pots is to open them up, big chance you did the same with the JD-990 encoder. I dont want to open this one up;), to complex and delicate pot.) maybe its a good id to just let it soak in switch cleaner solution/deoxit, what do you think?

I've been looking for a sci max for some time, hoping to find one cheaper than a sixtrak!.. good stuff!




--
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Re: Poly800 sometimes suffers from, verry low output volume / noisey output / only sound from right(left) output

2015-01-29 by berendnie@...

I like this video, kind of a comparison in differend ways of cleaning.
Potentiometer Cleaning Showdown
Potentiometer Cleaning Showdown
A comparison of various potentiometer cleaning methods, with a specif...
View on www.youtube.com
Preview by Yahoo

 

I live in the netherlands, i guess alot of the contact cleaners wil do.

Good stuff you fitted the Tauntek RAM/ROM, I had dreams of owning one ;) and doing a full pot, knob mod for full controll over all parameters and buttons, are the controlls over cc or sysex??.

The MIDI CPU from highly liquid, seems to be able to do the job, in my dream ;), a MAX/prophet600.

There's so much room in the MAX that you can probably fit 4 max brain/voice board's inside.

Yes it's a pitty, i saw one on ebay-usa some time ago, i asked the guy if he would ship it to me.. He never got back. this one was cheap.

Cheers! thanks for the help!

Re: [korgpolyex] Re: Poly800 sometimes suffers from, verry low output volume / noisey output / only sound from right(left) output

2015-01-29 by Louis Botterill

Hi,

I suspect if you're going to go as far as remove and disassemble the pot / fader you might as well replace it anyway, since you've done all the work. Unless you can't get the right part anymore.

Good idea on the air though. Forgot to mention that, I have a can of compressed spray air that I use to blow out dirt also (sometimes, not always needed at all).

I'm quite pleased with the MAX, just been playing around with it. Got some nice sounds. Even the original unmodified MAX has extensive MIDI CC control, one of the pioneers in that respect, coming from SCI you'd expect that. It has extensive control, everything has a MIDI CC.

So real easy to hook up a MIDI controller to it. Also I use the iPad and MidiDesigner (six-track template works) and my X-Station, I've made a template for the MAX on that.

I had an idea to take a MAX and make a little tabletop sound module (dump the keys, do the mods, put in a small new box) - think it would be nice. Just need to find more MAXs now.

Also I may change the LEDS for some different colours. Sad but fun, as it's really nice when the VCO LEDS flash away as it plays some notes, a little colour there might make it a little different. I'll do that next just for my own amusement. 

I wonder how many got thrown out and destroyed, they don't look good to some people (I quite like it!) - hopefully some more will be available at a good price for purchase and modification, unlike most other analog gear where the price just goes up and up until it's no longer worth the cost.

Have fun, good luck with the pots!

Louis



On 29 January 2015 at 19:06, berendnie@... [korgpolyex] <korgpolyex@yahoogroups.com> wrote:
 

I like this video, kind of a comparison in differend ways of cleaning.

Potentiometer Cleaning Showdown
Potentiometer Cleaning Showdown
A comparison of various potentiometer cleaning methods, with a specif...
Preview by Yahoo

 

I live in the netherlands, i guess alot of the contact cleaners wil do.

Good stuff you fitted the Tauntek RAM/ROM, I had dreams of owning one ;) and doing a full pot, knob mod for full controll over all parameters and buttons, are the controlls over cc or sysex??.

The MIDI CPU from highly liquid, seems to be able to do the job, in my dream ;), a MAX/prophet600.

There's so much room in the MAX that you can probably fit 4 max brain/voice board's inside.

Yes it's a pitty, i saw one on ebay-usa some time ago, i asked the guy if he would ship it to me.. He never got back. this one was cheap.

Cheers! thanks for the help!




--
Web: www.chillipower.com
Blog: http://louisbotterill.blogspot.com/
Twitter: http://twitter.com/BinaryJunkie
LinkedIn: http://uk.linkedin.com/pub/louis-botterill/10/3b2/265

“The trouble with the world is that the stupid are cocksure and the intelligent are full of doubt.” –Bertrand Russell

Please consider your environmental responsibility before printing this e-mail

Re: Poly800 sometimes suffers from, verry low output volume / noisey output / only sound from right(left) output

2015-01-29 by berendnie@...

Just took it out and let the pot part sit in isopropyl alcohol, i tried plumping al the solder off to take it off the board, but it took to long and i didn't want to damage the cicruit board pads! anyway.. it worked! (for now!).

Yes! sinds space is always an isue making a desktop version is a cool id.. and because it's just one big board, its pritty easy.

I had thought of chopping the poly800 in half.. but giving it wooden sides is not that easy.
Tho there's enough space to refit the chorus board somewhere els.. thus making it a 2 octave poly800 ;)!

Have you seen the roland juno160 mod ''the junoist 106'' ? for the MAX and the poly800 this would be much much!! easy'er, I wouldn't dare doing this to a juno106.. such a tied fit

So apparently you can hacksaw a keyboard pcb in half ;) wtf.. I like this id! dont know why i dont see it more often!

if i had an sci MAX i would do it without a dought. I love al there products and would never think of reselling it.

now about the leds, do the track leds in the sequencer, inecade if a voice is being played or?

Cheers
 

Re: [korgpolyex] Re: Poly800 sometimes suffers from, verry low output volume / noisey output / only sound from right(left) output

2015-01-30 by Louis Botterill

Glad you made progress with your noisy pot. Good idea not to risk damaging the PCB, that would be bad.

Yeah I might leave this MAX as-is, since after a clean up it's in pretty good condition for such an old synth, keyboard is like new.
However if I can find a second one that's in any condition, beaten up even, if it works at all electronically then I'd love to mod and hack it into a new form.
Been playing with it, it's much fun. Running an arpeggiator into it from my x-station then using the x-station to control all the params realtime, then put the max in unison mode. That's many hours of fun just there...

The LEDs, there's one per voice VCO, so they light whenever a voice sounds, whether plaid from internal sequencer, keyboard or external midi. Voices are CEM based, one per voice. That's why it can be 6 part multitimbral also.
The LEDs are fun things to watch, especially since the VCO voice algorithm is like some sort of hash function. If you're in poly mode and you have portmanteau on you get some unusual affects as the glide depends on which oscillator is selected to play the note and what that oscillator previously played, not what previous key you hit. It's really fun, makes for some creative riffs.

Time permitting I'd like to work out some enhancements on the analog voicing side, possibly a line-in to the filters/amps and maybe some sub-oscillator for extra depth in the bass.

Much fun. Looking forward to the Poly800 mods next. Have you considered a Poly800EX for a small form-factor?

I could never chop up a Juno 106. I have the later Alpha Juno 2 and one of its best attributes is the full size keys with aftertouch. Too nice to cut up.

Have fun, Louis



On 29 January 2015 at 21:34, berendnie@... [korgpolyex] <korgpolyex@yahoogroups.com> wrote:
 

Just took it out and let the pot part sit in isopropyl alcohol, i tried plumping al the solder off to take it off the board, but it took to long and i didn't want to damage the cicruit board pads! anyway.. it worked! (for now!).


Yes! sinds space is always an isue making a desktop version is a cool id.. and because it's just one big board, its pritty easy.

I had thought of chopping the poly800 in half.. but giving it wooden sides is not that easy.
Tho there's enough space to refit the chorus board somewhere els.. thus making it a 2 octave poly800 ;)!

Have you seen the roland juno160 mod ''the junoist 106'' ? for the MAX and the poly800 this would be much much!! easy'er, I wouldn't dare doing this to a juno106.. such a tied fit

So apparently you can hacksaw a keyboard pcb in half ;) wtf.. I like this id! dont know why i dont see it more often!

if i had an sci MAX i would do it without a dought. I love al there products and would never think of reselling it.

now about the leds, do the track leds in the sequencer, inecade if a voice is being played or?

Cheers
 




--
Web: www.chillipower.com
Blog: http://louisbotterill.blogspot.com/
Twitter: http://twitter.com/BinaryJunkie
LinkedIn: http://uk.linkedin.com/pub/louis-botterill/10/3b2/265

“The trouble with the world is that the stupid are cocksure and the intelligent are full of doubt.” –Bertrand Russell

Please consider your environmental responsibility before printing this e-mail