Korg Poly800/EX800 Users

Hey folks, I'm really glad I found this forum!  Nice work everyone.!


EXECUTIVE SUMMARY: I love this synth! But, I'm missing the joystick and need some info 
on rigging up some resistors to run in tune without it.


(Ok first, I'm not totally illiterate, just really excited by good/fun hardware synths)

So, I recently was given a tattered old poly-800 mk1 from a friend...Free is a really good 
price!

I was really skeptical about this unit when I read about it and even more skeptical when I 
got my hands on it and was loading it into my car because it felt like a total cheap piece 
of sh**t.  Plastic unit with crappy buttons and that stupid programming reference stencil 
area that should have been filled with a million knobs and switches...anyway...

I got it home, hacked together a power supply to turn it on...and you know the 
story...nothing, no sound...........oh wait if I hold the keys down I heard some kind of low 
fequency something coming in on a really slow envelope...I think...So I quickly referenced 
the manual, which amazingly was part of the deal, to put it into programming mode and 
set up everything to make a simple square wave, unfiltered, sane adsr settings...and sure 
enough...success...major success!!!  It actually worked...nice!

Oh dear, then I read about the battery issue in the manual....WHAT? NO INTERNAL 
BATTERY? You must be kidding me, seriously? come on...so I unplugged the dc power, 
plugged it back in, sure enough, everything was erased...no really, come on, really? 
seriously? come on korg...really?  YES REALLY. 

First order of business 3v lithium mod... (THANKS GUYS!)...works like a charm... Yes one 
step closer to a "real synth"...

Anyway, this synth, for certain applications, absolutely kills!  I love it to death...the factory 
presets are ridiculously bad...seriously all of them (even patch 15 ;) This thing sounds 
best when you open it right up loud and pure...I REALLY, REALLY, love the oscillators on 
this thing...and the filter sounds really good, but I'm going to do the 12db mod asap, I 
don't like 24db filters personally for the music I make...I prefer the more acidy sound of 
12db...

I have a Jupiter-8 and a Juptiter-6, and I hate to admit it, but this thing will make killer 
sounds not possible on those two machines...very complimentary...Retro Electro 
madness!!!!!...

Maybe you can tell...I love old keyboards...YYEEEEAAAAAAAHHHHHHH... <happy dance>

I'll upload some good "housey-technoy-elctroey-acidy-discoey-psy-ee" patches for 
everyone soon...

Ok, long, long, story short. (Thanks for listening)...


THE REAL MEAT OF THIS MESSAGE:

I'm missing the joystick unit completely, its not just broken, its gone, the whole unit...  I 
can stare down the square hole and see the connectors hanging there.

1) I think the pitch of the unit is being thrown off because there's no resistance on the 
pitch mod joystick, it's sounds about 5 tones off, yeah?

2) Would somebody be kind enough to tell me what resistors I should wire up to what 
leads to simulate the joystick being in the center? Please?  I'll buy you a case of beer or 
lunch, or write you a song, or something...I promise.

3) Does anybody want to sell me a joystick unit?  or know where I can get one?

Peace everybody, happy synthing... :) :) :) :) :) :)

On Wed, 2009-02-11 at 08:47 +0000, serotonic_sound wrote:

> Oh dear, then I read about the battery issue in the manual....WHAT? NO INTERNAL 
> BATTERY? You must be kidding me, seriously? come on...so I unplugged the dc power, 
> plugged it back in, sure enough, everything was erased...no really, come on, really? 
> seriously? come on korg...really?  YES REALLY. 

I've never seen one without an internal battery.  Maybe it's a UK thing,
every one through Korg UK had a battery fitted?

> Anyway, this synth, for certain applications, absolutely kills!  I love it to death...the factory 
> presets are ridiculously bad...seriously all of them (even patch 15 ;) This thing sounds 
> best when you open it right up loud and pure...I REALLY, REALLY, love the oscillators on 
> this thing...and the filter sounds really good, but I'm going to do the 12db mod asap, I 
> don't like 24db filters personally for the music I make...I prefer the more acidy sound of 
> 12db...

Well the classic TB303 is an 18dB/octave filter, on account of how they
couldn't squeeze the fourth capacitor and transistor pair into the
board...

> I'm missing the joystick unit completely, its not just broken, its gone, the whole unit...  I 
> can stare down the square hole and see the connectors hanging there.
> 
> 1) I think the pitch of the unit is being thrown off because there's no resistance on the 
> pitch mod joystick, it's sounds about 5 tones off, yeah?

Quite possible.  Does the pitch change if you move the bend depth
slider?

> 2) Would somebody be kind enough to tell me what resistors I should wire up to what 
> leads to simulate the joystick being in the center? Please?  I'll buy you a case of beer or 
> lunch, or write you a song, or something...I promise.

The pot is just used as a potential divider, so any two identical
resistors should be about right.  Looking at the circuit diagram it's a
10k pot on both axes of the stick, so a couple of 4.7k resistors should
do the job for you.

HTH
  Gordon

> I've never seen one without an internal battery.  Maybe it's a UK thing,
> every one through Korg UK had a battery fitted?

This board had the 3v battery lug islands, but no battery was ever installed (and it had R1 
and D2 installed )...

> Well the classic TB303 is an 18dB/octave filter, on account of how they
> couldn't squeeze the fourth capacitor and transistor pair into the
> board...

Indeed it did, On my Jupiter-8, I mainly use the 12db/oct setting...it sounds "harder", 
"nastier", "more rippin'", or what have you ... ;)

> Quite possible.  Does the pitch change if you move the bend depth
> slider?

Interestingly no, the "Bend" slider, does nothing with the joystick unplugged...at least on 
this unit...I didn't see any other weird mods when I was doing the battery mod.

> The pot is just used as a potential divider, so any two identical
> resistors should be about right.  Looking at the circuit diagram it's a
> 10k pot on both axes of the stick, so a couple of 4.7k resistors should
> do the job for you.

Thanks! I'll have a look at the circuit diagram, I assume its somewhere in the 'files" section 
and it has the pin numbers for the joystick...

Thanks for your help...bed time in Canada...<yawn> l8r

Hello again folks...I hope everyone is doin' alright...

So it turns out, according to the schematics, that, I'm missing the "KLM-599 Joystick" 
board completely.  I'm not exactly sure what this board looks like but I have connector 1B 
and 8B just hanging loose inside the chassis.

I'm not really interested in replacing the joystick at this point...I doubt I'd use it much 
anyway...

Can any of you help me out rigging something up to get the unit so it plays in tune again?

Gordon, you said I could potentially wire up a couple of 4.7K resistors...but it looks like 
that board has a few more components, where would I install these resistors exactly given 
that I'm missing the entire joystick assembly and board?

Any help you guys could offer me is REALLY appreciated...

Of course, I could just get by practicing my up a fourth, down a fifty, transposition skills 
but I'd rather not.  (I actually had a guitar teacher once who claimed that he played in a big 
band and would intentionally tune his guitar 1 or 2 semitones out just to practice his live 
transposition skills and avoid boredom playing the old standards)...jeez...

Oh, here's a thought, is there a course-tune master trimpot somewhere that I could adjust 
instead of trying to simulate the joystick board somehow?

Later Y'all,
-Tim






-- In korgpolyex@yahoogroups.com, "Gordon J. C. Pearce MM3YEQ" <gordon@...> wrote:
>
> On Wed, 2009-02-11 at 08:47 +0000, serotonic_sound wrote:
> 
> > Oh dear, then I read about the battery issue in the manual....WHAT? NO INTERNAL 
> > BATTERY? You must be kidding me, seriously? come on...so I unplugged the dc 
power, 
> > plugged it back in, sure enough, everything was erased...no really, come on, really? 
> > seriously? come on korg...really?  YES REALLY. 
> 
> I've never seen one without an internal battery.  Maybe it's a UK thing,
> every one through Korg UK had a battery fitted?
> 
> > Anyway, this synth, for certain applications, absolutely kills!  I love it to death...the 
factory 
> > presets are ridiculously bad...seriously all of them (even patch 15 ;) This thing sounds 
> > best when you open it right up loud and pure...I REALLY, REALLY, love the oscillators 
on 
> > this thing...and the filter sounds really good, but I'm going to do the 12db mod asap, I 
> > don't like 24db filters personally for the music I make...I prefer the more acidy sound 
of 
> > 12db...
> 
> Well the classic TB303 is an 18dB/octave filter, on account of how they
> couldn't squeeze the fourth capacitor and transistor pair into the
> board...
> 
> > I'm missing the joystick unit completely, its not just broken, its gone, the whole unit...  
I 
> > can stare down the square hole and see the connectors hanging there.
> > 
> > 1) I think the pitch of the unit is being thrown off because there's no resistance on the 
> > pitch mod joystick, it's sounds about 5 tones off, yeah?
> 
> Quite possible.  Does the pitch change if you move the bend depth
> slider?
> 
> > 2) Would somebody be kind enough to tell me what resistors I should wire up to what 
> > leads to simulate the joystick being in the center? Please?  I'll buy you a case of beer 
or 

> > lunch, or write you a song, or something...I promise.
> 
> The pot is just used as a potential divider, so any two identical
> resistors should be about right.  Looking at the circuit diagram it's a
> 10k pot on both axes of the stick, so a couple of 4.7k resistors should
> do the job for you.
> 
> HTH
>   Gordon
>

--- In korgpolyex@yahoogroups.com, "serotonic_sound" <sero-tonic@...> 
wrote:
>> Oh, here's a thought, is there a course-tune master trimpot 
somewhere that I could adjust 
> instead of trying to simulate the joystick board somehow?

the internal pots are:

VR1 - DCO Pitch adjust 
VR2 - VCF Frequency adjust 
VR3 - White Noise level adjust 
VR4 - DCO Fine tune adjust 
VR5 - VCF resonance adjust

On Thu, 2009-02-12 at 08:44 +0000, serotonic_sound wrote:

> Gordon, you said I could potentially wire up a couple of 4.7K resistors...but it looks like 
> that board has a few more components, where would I install these resistors exactly given 
> that I'm missing the entire joystick assembly and board?

I'll dig out the Poly-800 and draw out the circuit of the joystick board
later today.

Gordon

Hey Mike,

Thanks for your help...I did what you recommended...I'm not sure what you were 
expecting the results to be but I'm getting the following:

1) The pitch pot only works the first half of its range.  From Full Left To Center increases 
the pitch from about a 5th down to normal.  But, the second half (Center to Right) does 
nothing.  I would have expected the pitch to rise above normal.

2) The Mod pot also only does something through the first half of its range...I don't know 
exactly what the behaviour of the joystick was originally, but I find that with the DCO 
amplitude mod parameter set to 0 I can mod the dco mod go to 15 with the pot. (Its at 15 
when the pot is in the middle).  With DCO set to zero the pot does nothing to the DCO.  
With the vcf mod parameter set to zero the pot does nothing to the vcf.  With the vcf set to 
full, the pot increases the vcf from off to full.

I used all the wires from the existing 1b connector and tapped -5 (blue) to one side of the 
pots, +5 (red) to the other side of the pots.  Then attached one middle post to 1-4B and 
the other middle post to 1-5b...Sound right?

I verified that the pots are sending -5 through +5 volts with zero in the middle through 
1-4B and 1-5B.

I can play in tune again, but the results aren't quite what I was expecting...

What do you think?

Thanks again for your help...
-Tim



--- In korgpolyex@yahoogroups.com, Michael Hawkins <korgpolyex800@...> wrote:
>
> If I were in your situation I wouldn't touch the existing trim pots.
> 
> And, I would use two 10K linear pots or trimpots to fake the missing joystick assembly.
> 
> Connect the left and the right side of both pots to -5V and +5V.
> 
> And connect the wipers of each to connect pin 1-4B and 1-5B.
> 
> This will allow you to set the VCF/DCO modulation to zero as well as pitch bend.
> 
> If you use pots you could even make a plate to go over the joystick hole and mount the 
pots right there.
> 
> I still think you should pop a new joystick in there though. LOL
> 
> Mike.
> 
> 
> 
> 
> ________________________________
> From: Gordon J. C. Pearce MM3YEQ <gordon@...>
> To: korgpolyex@yahoogroups.com
> Sent: Thursday, February 12, 2009 6:44:20 AM
> Subject: Re: [korgpolyex] Missing Joystick board (KLM-599) "mod"
> 
> 
> On Thu, 2009-02-12 at 08:44 +0000, serotonic_sound wrote:
> 
> > Gordon, you said I could potentially wire up a couple of 4.7K resistors... but it looks 
like 
> > that board has a few more components, where would I install these resistors exactly 
given 

> > that I'm missing the entire joystick assembly and board?
> 
> I'll dig out the Poly-800 and draw out the circuit of the joystick board
> later today.
> 
> Gordon
>

Actually, I wasn't quite right in my description.  The vcf isn't affected at all by the mod 
pot.

-Tim


--- In korgpolyex@yahoogroups.com, "serotonic_sound" <sero-tonic@...> wrote:
>
> Hey Mike,
> 
> Thanks for your help...I did what you recommended...I'm not sure what you were 
> expecting the results to be but I'm getting the following:
> 
> 1) The pitch pot only works the first half of its range.  From Full Left To Center increases 
> the pitch from about a 5th down to normal.  But, the second half (Center to Right) does 
> nothing.  I would have expected the pitch to rise above normal.
> 
> 2) The Mod pot also only does something through the first half of its range...I don't 
know 
> exactly what the behaviour of the joystick was originally, but I find that with the DCO 
> amplitude mod parameter set to 0 I can mod the dco mod go to 15 with the pot. (Its at 
15 
> when the pot is in the middle).  With DCO set to zero the pot does nothing to the DCO.  
> With the vcf mod parameter set to zero the pot does nothing to the vcf.  With the vcf set 
to 
> full, the pot increases the vcf from off to full.
> 
> I used all the wires from the existing 1b connector and tapped -5 (blue) to one side of 
the 
> pots, +5 (red) to the other side of the pots.  Then attached one middle post to 1-4B and 
> the other middle post to 1-5b...Sound right?
> 
> I verified that the pots are sending -5 through +5 volts with zero in the middle through 
> 1-4B and 1-5B.
> 
> I can play in tune again, but the results aren't quite what I was expecting...
> 
> What do you think?
> 
> Thanks again for your help...
> -Tim
> 
> 
> 
> --- In korgpolyex@yahoogroups.com, Michael Hawkins <korgpolyex800@> wrote:
> >
> > If I were in your situation I wouldn't touch the existing trim pots.
> > 
> > And, I would use two 10K linear pots or trimpots to fake the missing joystick 
assembly.
> > 
> > Connect the left and the right side of both pots to -5V and +5V.
> > 
> > And connect the wipers of each to connect pin 1-4B and 1-5B.
> > 
> > This will allow you to set the VCF/DCO modulation to zero as well as pitch bend.
> > 
> > If you use pots you could even make a plate to go over the joystick hole and mount 
the 
> pots right there.
> > 
> > I still think you should pop a new joystick in there though. LOL
> > 
> > Mike.
> > 
> > 
> > 
> > 
> > ________________________________
> > From: Gordon J. C. Pearce MM3YEQ <gordon@>
> > To: korgpolyex@yahoogroups.com
> > Sent: Thursday, February 12, 2009 6:44:20 AM
> > Subject: Re: [korgpolyex] Missing Joystick board (KLM-599) "mod"
> > 
> > 
> > On Thu, 2009-02-12 at 08:44 +0000, serotonic_sound wrote:
> > 
> > > Gordon, you said I could potentially wire up a couple of 4.7K resistors... but it looks 
> like 
> > > that board has a few more components, where would I install these resistors 
exactly 

> given 
> > > that I'm missing the entire joystick assembly and board?
> > 
> > I'll dig out the Poly-800 and draw out the circuit of the joystick board
> > later today.
> > 
> > Gordon
> >
>

No luck, the pitch pot still only works for the first half of its range. :(

But the mod pot now controls the vcf instead of the dco,  When this pot is full right, the 
vcf mod is off, it turns on full really quickly (maybe through the joystick's deadzone only?) 
right around 1/2 way (as I turn it left)...

Here's how I have it now:  Both right posts are connected to +5, Both left posts are 
connected to ground.  1 middle post is connected to 1-4b and the other middle post is 
connected to 1-5b.   The -5V wire on the connector is not connected to anything.  The 
voltage on the middle pins now varies from 5V to 0V.

I have an extremely limited knowledge of hardware.  But from a rookie deduction 
standpoint, I would assume all of the wires on the connector must have to be used.  It 
seems to make sense that this is true because now the DCO can't be controlled whereas 
with the -5 connected it could, why else would they have the pins on the connector live? 
I'd play around a bit with it myself but I'm scared of frying something, and I don't have any 
alligator clips so experimenting is fairly painful ...

Is this starting to make any sense to you at all Mike?

Thanks for your time!...

-Tim

--- In korgpolyex@yahoogroups.com, Michael Hawkins <korgpolyex800@...> wrote:
>
> Hi Tim,
> 
> let's try this.
> 
> Connect the -5V side of the pots to ground.
> 
> Mike.
> 
> 
> 
> ________________________________
> From: serotonic_sound <sero-tonic@...>
> To: korgpolyex@yahoogroups.com
> Sent: Monday, February 16, 2009 11:02:30 PM
> Subject: [korgpolyex] Re: Missing Joystick board (KLM-599) "mod"
> 
> 
> Actually, I wasn't quite right in my description.  The vcf isn't affected at all by the mod 
> pot.
> 
> -Tim
> 
> --- In korgpolyex@yahoogro ups.com, "serotonic_sound" <sero-tonic@ ...> wrote:
> >
> > Hey Mike,
> > 
> > Thanks for your help...I did what you recommended. ..I'm not sure what you were 
> > expecting the results to be but I'm getting the following:
> > 
> > 1) The pitch pot only works the first half of its range.  From Full Left To Center 
increases 
> > the pitch from about a 5th down to normal.  But, the second half (Center to Right) 
does 
> > nothing.  I would have expected the pitch to rise above normal.
> > 
> > 2) The Mod pot also only does something through the first half of its range...I don't 
> know 
> > exactly what the behaviour of the joystick was originally, but I find that with the DCO 
> > amplitude mod parameter set to 0 I can mod the dco mod go to 15 with the pot. (Its at 
> 15 
> > when the pot is in the middle).  With DCO set to zero the pot does nothing to the 
DCO. 
> > With the vcf mod parameter set to zero the pot does nothing to the vcf.  With the vcf 
set 
> to 
> > full, the pot increases the vcf from off to full.
> > 
> > I used all the wires from the existing 1b connector and tapped -5 (blue) to one side of 
> the 
> > pots, +5 (red) to the other side of the pots.  Then attached one middle post to 1-4B 
and 
> > the other middle post to 1-5b...Sound right?
> > 
> > I verified that the pots are sending -5 through +5 volts with zero in the middle 
through 
> > 1-4B and 1-5B.
> > 
> > I can play in tune again, but the results aren't quite what I was expecting...
> > 
> > What do you think?
> > 
> > Thanks again for your help...
> > -Tim
> > 
> > 
> > 
> > --- In korgpolyex@yahoogro ups.com, Michael Hawkins <korgpolyex800@ > wrote:
> > >
> > > If I were in your situation I wouldn't touch the existing trim pots.
> > > 
> > > And, I would use two 10K linear pots or trimpots to fake the missing joystick 
> assembly.
> > > 
> > > Connect the left and the right side of both pots to -5V and +5V.
> > > 
> > > And connect the wipers of each to connect pin 1-4B and 1-5B.
> > > 
> > > This will allow you to set the VCF/DCO modulation to zero as well as pitch bend.
> > > 
> > > If you use pots you could even make a plate to go over the joystick hole and mount 
> the 
> > pots right there.
> > > 
> > > I still think you should pop a new joystick in there though. LOL
> > > 
> > > Mike.
> > > 
> > > 
> > > 
> > > 
> > > ____________ _________ _________ __
> > > From: Gordon J. C. Pearce MM3YEQ <gordon@>
> > > To: korgpolyex@yahoogro ups.com
> > > Sent: Thursday, February 12, 2009 6:44:20 AM
> > > Subject: Re: [korgpolyex] Missing Joystick board (KLM-599) "mod"
> > > 
> > > 
> > > On Thu, 2009-02-12 at 08:44 +0000, serotonic_sound wrote:
> > > 
> > > > Gordon, you said I could potentially wire up a couple of 4.7K resistors... but it 
looks 

> > like 
> > > > that board has a few more components, where would I install these resistors 
> exactly 
> > given 
> > > > that I'm missing the entire joystick assembly and board?
> > > 
> > > I'll dig out the Poly-800 and draw out the circuit of the joystick board
> > > later today.
> > > 
> > > Gordon
> > >
> >
>

--- In korgpolyex@yahoogroups.com, "serotonic_sound" <sero-tonic@...> 
wrote:
>
> 
>  it turns on full really quickly (maybe through the joystick's 
deadzone only?) 
> right around 1/2 way (as I turn it left)...
> 

Sounds like a liner pot being used where a log one should be used.  
Or vice-versa.


> Here's how I have it now:  Both right posts are connected to +5, 
Both left posts are 
> connected to ground.  1 middle post is connected to 1-4b and the 
other middle post is 
> connected to 1-5b.   The -5V wire on the connector is not connected 
to anything.  The 
> voltage on the middle pins now varies from 5V to 0V.
> 

I think you should try wiring the pot as a variable resistor, using 
only two pins (wiper/middle and one of the outer pins), and possibly 
short the wiper to the unused pin for smoother operation.

I've been fiddling around with crossing the wires from the 1b connector that went to the 
missing joystick board and have managed to thoroughly confuse myself.  There's some 
crazy digital latching with the pitch control going on that I wasn't expecting to find, and 
most definitely don't understand...

If I apply an instantaneous (touch and remove) +5 volts to 1-4A the machine latches down 
a fifth, if I apply -5V OR ground, it latches up a fifth. Anyway:

A couple of questions, if somebody would be so kind as to answer:

1) What is the original behaviour of the joystick?  What is the pitch bend range and how 
does the vcf/dco joystick axis interact with the patch parameters?

2) I see the KLM-599 Joystick board on the schematics, but, where are the variable 
resistors that represent the stick axes?

3) Can anybody out there make sense of what the components on the joystick board 
schematics do?

Thanks,
-Tim  

--- In korgpolyex@yahoogroups.com, Michael Hawkins <korgpolyex800@...> wrote:
>
> Hi Tim,
> 
> let's try this.
> 
> Connect the -5V side of the pots to ground.
> 
> Mike.
> 
> 
> 
> ________________________________
> From: serotonic_sound <sero-tonic@...>
> To: korgpolyex@yahoogroups.com
> Sent: Monday, February 16, 2009 11:02:30 PM
> Subject: [korgpolyex] Re: Missing Joystick board (KLM-599) "mod"
> 
> 
> Actually, I wasn't quite right in my description.  The vcf isn't affected at all by the mod 
> pot.
> 
> -Tim
> 
> --- In korgpolyex@yahoogro ups.com, "serotonic_sound" <sero-tonic@ ...> wrote:
> >
> > Hey Mike,
> > 
> > Thanks for your help...I did what you recommended. ..I'm not sure what you were 
> > expecting the results to be but I'm getting the following:
> > 
> > 1) The pitch pot only works the first half of its range.  From Full Left To Center 
increases 
> > the pitch from about a 5th down to normal.  But, the second half (Center to Right) 
does 
> > nothing.  I would have expected the pitch to rise above normal.
> > 
> > 2) The Mod pot also only does something through the first half of its range...I don't 
> know 
> > exactly what the behaviour of the joystick was originally, but I find that with the DCO 
> > amplitude mod parameter set to 0 I can mod the dco mod go to 15 with the pot. (Its at 
> 15 
> > when the pot is in the middle).  With DCO set to zero the pot does nothing to the 
DCO. 
> > With the vcf mod parameter set to zero the pot does nothing to the vcf.  With the vcf 
set 
> to 
> > full, the pot increases the vcf from off to full.
> > 
> > I used all the wires from the existing 1b connector and tapped -5 (blue) to one side of 
> the 
> > pots, +5 (red) to the other side of the pots.  Then attached one middle post to 1-4B 
and 
> > the other middle post to 1-5b...Sound right?
> > 
> > I verified that the pots are sending -5 through +5 volts with zero in the middle 
through 
> > 1-4B and 1-5B.
> > 
> > I can play in tune again, but the results aren't quite what I was expecting...
> > 
> > What do you think?
> > 
> > Thanks again for your help...
> > -Tim
> > 
> > 
> > 
> > --- In korgpolyex@yahoogro ups.com, Michael Hawkins <korgpolyex800@ > wrote:
> > >
> > > If I were in your situation I wouldn't touch the existing trim pots.
> > > 
> > > And, I would use two 10K linear pots or trimpots to fake the missing joystick 
> assembly.
> > > 
> > > Connect the left and the right side of both pots to -5V and +5V.
> > > 
> > > And connect the wipers of each to connect pin 1-4B and 1-5B.
> > > 
> > > This will allow you to set the VCF/DCO modulation to zero as well as pitch bend.
> > > 
> > > If you use pots you could even make a plate to go over the joystick hole and mount 
> the 
> > pots right there.
> > > 
> > > I still think you should pop a new joystick in there though. LOL
> > > 
> > > Mike.
> > > 
> > > 
> > > 
> > > 
> > > ____________ _________ _________ __
> > > From: Gordon J. C. Pearce MM3YEQ <gordon@>
> > > To: korgpolyex@yahoogro ups.com
> > > Sent: Thursday, February 12, 2009 6:44:20 AM
> > > Subject: Re: [korgpolyex] Missing Joystick board (KLM-599) "mod"
> > > 
> > > 
> > > On Thu, 2009-02-12 at 08:44 +0000, serotonic_sound wrote:
> > > 
> > > > Gordon, you said I could potentially wire up a couple of 4.7K resistors... but it 
looks 

> > like 
> > > > that board has a few more components, where would I install these resistors 
> exactly 
> > given 
> > > > that I'm missing the entire joystick assembly and board?
> > > 
> > > I'll dig out the Poly-800 and draw out the circuit of the joystick board
> > > later today.
> > > 
> > > Gordon
> > >
> >
>

On Wed, 2009-02-18 at 05:40 -0800, Michael Hawkins wrote:
> Tim,
> 
> I recommend you wait until we have a bit more discussion about the
> operation of the joystick board.
> 
> I wouldn't want to see you blow your Poly up.
> 
> I am quite busy today, but will attempt to provide some additional
> instructions tomorrow.
> 
> Zoinky is right that we need to use linear pots. What are all of the
> markings on your pot's? When you move the pots through their full
> rotation, does the voltage move smoothly or does it move slowly and
> then at each end, suddenly jump up or down?

The pots are a bit funny, with a kind of centre-tap on them.

As far as the output from the joystick board goes, there are two
connectors - CN1B and CN8B.  CN8B goes to the bend range slider, CN1B
goes to CN1A on the main board.  CN1A is as follows:
1 - +5v
2 - 0v
3 - -5v
4 - X output
5 - Y output

The X and Y outputs are centred around 2v, and go from 0v fully right or
up to 4v fully left or down.

I haven't drawn out the circuit on the joystick PCB yet, but I suspect
it's some sort of voltage regulator and biasing thing.

Have a look at the circuit below for an idea of what might work.

http://www.gjcp.net/synth/joystick.jpg

Gordon

> Zoinky is right that we need to use linear pots. What are all of the
> markings on your pot's? When you move the pots through their full
> rotation, does the voltage move smoothly or does it move slowly and
> then at each end, suddenly jump up or down?

The pots I have are new 10K linear pots and they indeed look/feel
linear when I measure them on my voltmeter.  I think all they say is
"10K B" somewhere but I don't have them in front of me right now.

When I sent 0 to 5V through the pitch bend (1-5B).  The pitch bend
went from down a fifth to normal at 12 o'clock, but did nothing for
the rest of the range.  This happened with +5 connected, the wiper
connected to 1-5B, and either ground or -5V to the other side.  And it
did feel "smooth/linear" from far left to 12 o'clock.

What is the range (in musical terms) of the joystick?

Thanks for your help you guys.

-Tim


--- In korgpolyex@yahoogroups.com, "Gordon J. C. Pearce MM3YEQ"
<gordon@...> wrote:

>
> On Wed, 2009-02-18 at 05:40 -0800, Michael Hawkins wrote:
> > Tim,
> > 
> > I recommend you wait until we have a bit more discussion about the
> > operation of the joystick board.
> > 
> > I wouldn't want to see you blow your Poly up.
> > 
> > I am quite busy today, but will attempt to provide some additional
> > instructions tomorrow.
> > 
> > Zoinky is right that we need to use linear pots. What are all of the
> > markings on your pot's? When you move the pots through their full
> > rotation, does the voltage move smoothly or does it move slowly and
> > then at each end, suddenly jump up or down?
> 
> The pots are a bit funny, with a kind of centre-tap on them.
> 
> As far as the output from the joystick board goes, there are two
> connectors - CN1B and CN8B.  CN8B goes to the bend range slider, CN1B
> goes to CN1A on the main board.  CN1A is as follows:
> 1 - +5v
> 2 - 0v
> 3 - -5v
> 4 - X output
> 5 - Y output
> 
> The X and Y outputs are centred around 2v, and go from 0v fully right or
> up to 4v fully left or down.
> 
> I haven't drawn out the circuit on the joystick PCB yet, but I suspect
> it's some sort of voltage regulator and biasing thing.
> 
> Have a look at the circuit below for an idea of what might work.
> 
> http://www.gjcp.net/synth/joystick.jpg
> 
> Gordon
>

On Thu, 2009-02-19 at 01:28 +0000, serotonic_sound wrote:
> > Zoinky is right that we need to use linear pots. What are all of the
> > markings on your pot's? When you move the pots through their full
> > rotation, does the voltage move smoothly or does it move slowly and
> > then at each end, suddenly jump up or down?
> 
> The pots I have are new 10K linear pots and they indeed look/feel
> linear when I measure them on my voltmeter.  I think all they say is
> "10K B" somewhere but I don't have them in front of me right now.

The pots on the joystick say 10K B.  I suspect they're 10k over a very
short swing though, because obviously they can't turn through a wide
angle.

> When I sent 0 to 5V through the pitch bend (1-5B).  The pitch bend
> went from down a fifth to normal at 12 o'clock, but did nothing for
> the rest of the range.  This happened with +5 connected, the wiper
> connected to 1-5B, and either ground or -5V to the other side.  And it
> did feel "smooth/linear" from far left to 12 o'clock.

Well, as I said, the X and Y pins definitely go from 0 to 4 volts, with
2 volts in the centre.

> What is the range (in musical terms) of the joystick?

Mine swings around 10 semitones.

Gordon

On Thu, 2009-02-19 at 05:20 -0800, Michael Hawkins wrote:

> So my idea was to patch two -5 thru +5 voltages directly onto the
> demultiplexer inputs thus bypassing all of that. And I chose -5 to +5
> because it wouldn't hurt to have the range go negative but I believe
> that 0V thru 5V should do it.
> 
> And I am very disappointed that it didn't work.
> 
> If I were you, I would try to find a replacement joystick unit.
> 
> The range of the joystick with the bend depth pot set to max is about
> 7 semitones (or half an octave up or down).
> 
> I still think that a range of 0V to +5V on those two pins should do
> the job. I am rather mystified as to why that wouldn't work.

I've actually measured it on my Poly-800, and it swings from 0 to 4
volts, not 5 volts.  The opamp keeps the pitch bend voltage centred
around 2v (so that at half-scale it would go from 1 to 3 volts).

HTH,
  Gordon

I finally got some more time to spend with the poly-800.  It seems 
that the 0 to 5v on 1-4B and 1-5B with 10K linear pots does actually 
work and provide what seems to be the full range on both axes of the 
stick.

I know absolutely for sure the first time I tried this it wasn't 
working correctly.  I think perhaps my unit got itself into a bad 
state, or maybe I missed putting a couple of parameters back into 
their valid ranges, or maybe my unit is generally flakey.   I took 
the battery out, unplugged it, turned it off, gave everything a good 
clean, let it sit for a while, then put everything back together, 
reset all the parameter ranges to their valid values and the joystick 
knobs seem to be functioning more or less correctly.

Thanks for you help you guys...

-Tim

--- In korgpolyex@yahoogroups.com, "Gordon J. C. Pearce MM3YEQ" 
<gordon@...> wrote:
>
> On Thu, 2009-02-19 at 05:20 -0800, Michael Hawkins wrote:
> 
> > So my idea was to patch two -5 thru +5 voltages directly onto the
> > demultiplexer inputs thus bypassing all of that. And I chose -5 
to +5
> > because it wouldn't hurt to have the range go negative but I 
believe
> > that 0V thru 5V should do it.
> > 
> > And I am very disappointed that it didn't work.
> > 
> > If I were you, I would try to find a replacement joystick unit.
> > 
> > The range of the joystick with the bend depth pot set to max is 
about
> > 7 semitones (or half an octave up or down).
> > 
> > I still think that a range of 0V to +5V on those two pins should 
do

> > the job. I am rather mystified as to why that wouldn't work.
> 
> I've actually measured it on my Poly-800, and it swings from 0 to 4
> volts, not 5 volts.  The opamp keeps the pitch bend voltage centred
> around 2v (so that at half-scale it would go from 1 to 3 volts).
> 
> HTH,
>   Gordon
>