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Discussion about the Korg PolySix synthesizer

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Tuning Issue--the opto is replaced

Tuning Issue--the opto is replaced

2012-03-31 by genetik

Hi, I just picked up a polysix with the battery replaced and board cleaned up. Everything is functional. The only issue is tuning. I followed the service manual and cannot get the synth in tune. It seems like the range of the VRs for the oscillators. If the high note C is in tune, the VR maxed out is still not C. And visa versa. After tuning high C at C6 with 4', C2 cannot be set to 0 cents either. It is more like A or A#. The scaling seems off. The opto is replaced with a VTL5C3 that tests correctly and has a fine-tuning resistor that i set at 1k2. Only that that seems weird is that when I put the test lead of my multimeter of pin 6 of the connector for keyboard tracking it shows -5V. VR5 and VR2 seem to do nothing. Help!

RE: [PolySix] Tuning Issue--the opto is replaced

2012-03-31 by backshall1

When using a trimmer resistor (I assume it replaces R93) with a new
opto-coupler, it is best to set all other VRs (VR1,2,3) to mid-point, set
the trimmer where you get the best scaling, and start from there. VR4 and 5
are not associated with tuning.

Also, try adjusting VR14, marked D#4-E4. This adjusts the scaling for the
upper end of the keyboard.

Don B.



_____

From: PolySix@yahoogroups.com [mailto:PolySix@yahoogroups.com] On Behalf Of
genetik
Sent: Friday, March 30, 2012 9:53 PM
To: PolySix@yahoogroups.com
Subject: [PolySix] Tuning Issue--the opto is replaced





Hi, I just picked up a polysix with the battery replaced and board cleaned
up. Everything is functional. The only issue is tuning. I followed the
service manual and cannot get the synth in tune. It seems like the range of
the VRs for the oscillators. If the high note C is in tune, the VR maxed out
is still not C. And visa versa. After tuning high C at C6 with 4', C2 cannot
be set to 0 cents either. It is more like A or A#. The scaling seems off.
The opto is replaced with a VTL5C3 that tests correctly and has a
fine-tuning resistor that i set at 1k2. Only that that seems weird is that
when I put the test lead of my multimeter of pin 6 of the connector for
keyboard tracking it shows -5V. VR5 and VR2 seem to do nothing. Help!





[Non-text portions of this message have been removed]

Re: [PolySix] Tuning Issue--the opto is replaced

2012-03-31 by Hayden Van Moskowitz

There was a trimmer resistor replaced. I saw your advice in another thread and tried this, but it seemed the resistor had no real effect on scaling. I hooked up a meter to it and just set it at 1k2 which seemed like a suggested resistance. If I get the oscillators high tuning tuned at C when playing C6, when I play C2 there is no way for me to get it in tune to C (not even close) with just VR1, 2, and 3 (especially considering VR2 doesn't do anything).

On Mar 31, 2012, at 8:46 AM, backshall1 wrote:

> When using a trimmer resistor (I assume it replaces R93) with a new
> opto-coupler, it is best to set all other VRs (VR1,2,3) to mid-point, set
> the trimmer where you get the best scaling, and start from there. VR4 and 5
> are not associated with tuning.
>
> Also, try adjusting VR14, marked D#4-E4. This adjusts the scaling for the
> upper end of the keyboard.
>
> Don B.
>
> _____
>
> From: PolySix@yahoogroups.com [mailto:PolySix@yahoogroups.com] On Behalf Of
> genetik
> Sent: Friday, March 30, 2012 9:53 PM
> To: PolySix@yahoogroups.com
> Subject: [PolySix] Tuning Issue--the opto is replaced
>
> Hi, I just picked up a polysix with the battery replaced and board cleaned
> up. Everything is functional. The only issue is tuning. I followed the
> service manual and cannot get the synth in tune. It seems like the range of
> the VRs for the oscillators. If the high note C is in tune, the VR maxed out
> is still not C. And visa versa. After tuning high C at C6 with 4', C2 cannot
> be set to 0 cents either. It is more like A or A#. The scaling seems off.
> The opto is replaced with a VTL5C3 that tests correctly and has a
> fine-tuning resistor that i set at 1k2. Only that that seems weird is that
> when I put the test lead of my multimeter of pin 6 of the connector for
> keyboard tracking it shows -5V. VR5 and VR2 seem to do nothing. Help!
>
> [Non-text portions of this message have been removed]
>
>



[Non-text portions of this message have been removed]

RE: [PolySix] Tuning Issue--the opto is replaced

2012-03-31 by backshall1

Wow, the trimmer has no real effect on scaling? Something is wrong there.
Maybe the trimmer's maximum value is too small. I have never used a VTL5C3
and I see that note in the "files" section where somebody used a 1k2
resistor, but I have used a VTL5C2 that needed about 22K and an NSL-32 that
needed about 39K.

Don B.

-----Original Message-----
From: PolySix@yahoogroups.com [mailto:PolySix@yahoogroups.com] On Behalf Of
Hayden Van Moskowitz
Sent: Saturday, March 31, 2012 10:19 AM
To: PolySix@yahoogroups.com
Subject: Re: [PolySix] Tuning Issue--the opto is replaced

There was a trimmer resistor replaced. I saw your advice in another thread
and tried this, but it seemed the resistor had no real effect on scaling. I
hooked up a meter to it and just set it at 1k2 which seemed like a suggested
resistance. If I get the oscillators high tuning tuned at C when playing C6,
when I play C2 there is no way for me to get it in tune to C (not even
close) with just VR1, 2, and 3 (especially considering VR2 doesn't do
anything).

On Mar 31, 2012, at 8:46 AM, backshall1 wrote:

> When using a trimmer resistor (I assume it replaces R93) with a new
> opto-coupler, it is best to set all other VRs (VR1,2,3) to mid-point, set
> the trimmer where you get the best scaling, and start from there. VR4 and
5
> are not associated with tuning.
>
> Also, try adjusting VR14, marked D#4-E4. This adjusts the scaling for the
> upper end of the keyboard.
>
> Don B.
>
> _____
>
> From: PolySix@yahoogroups.com [mailto:PolySix@yahoogroups.com] On Behalf
Of
> genetik
> Sent: Friday, March 30, 2012 9:53 PM
> To: PolySix@yahoogroups.com
> Subject: [PolySix] Tuning Issue--the opto is replaced
>
> Hi, I just picked up a polysix with the battery replaced and board cleaned
> up. Everything is functional. The only issue is tuning. I followed the
> service manual and cannot get the synth in tune. It seems like the range
of
> the VRs for the oscillators. If the high note C is in tune, the VR maxed
out
> is still not C. And visa versa. After tuning high C at C6 with 4', C2
cannot
> be set to 0 cents either. It is more like A or A#. The scaling seems off.
> The opto is replaced with a VTL5C3 that tests correctly and has a
> fine-tuning resistor that i set at 1k2. Only that that seems weird is that
> when I put the test lead of my multimeter of pin 6 of the connector for
> keyboard tracking it shows -5V. VR5 and VR2 seem to do nothing. Help!
>
> [Non-text portions of this message have been removed]
>
>



[Non-text portions of this message have been removed]



------------------------------------

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Re: [PolySix] Tuning Issue--the opto is replaced

2012-03-31 by Hayden Van Moskowitz

Actually this resistor has a very large maximum value so I can easily get it to 22k. But like I said, it seems to have no obvious effect.

On Mar 31, 2012, at 10:58 AM, backshall1 wrote:

> NSL-32



[Non-text portions of this message have been removed]

Re: Tuning Issue--the opto is replaced

2012-05-25 by fatmanstomach

Similarly, I too just replaced the opto--but I used a Silonex NSL-32. But, before and after the replacement, I have the same problem as you: -5V on CN05-6, and VR2 and VR5 don't do anything. Did you ever resolve this? Can anyone chime in if they're aware of an error in the service manual where it asks for
+1.6V on CN05-6. VR5 is in fact the KBD TRACK VR, right?

--- In PolySix@yahoogroups.com, "genetik" <haydenvan@...> wrote:
>
> Hi, I just picked up a polysix with the battery replaced and board cleaned up. Everything is functional. The only issue is tuning. I followed the service manual and cannot get the synth in tune. It seems like the range of the VRs for the oscillators. If the high note C is in tune, the VR maxed out is still not C. And visa versa. After tuning high C at C6 with 4', C2 cannot be set to 0 cents either. It is more like A or A#. The scaling seems off. The opto is replaced with a VTL5C3 that tests correctly and has a fine-tuning resistor that i set at 1k2. Only that that seems weird is that when I put the test lead of my multimeter of pin 6 of the connector for keyboard tracking it shows -5V. VR5 and VR2 seem to do nothing. Help!
>

Re: [PolySix] Tuning Issue--the opto is replaced

2014-01-07 by <mzaec@mail.ru>

Hi everyone!

I've read this forum and I see that people have the same problem with PolySix as mine.

It turned out that the problem is not in opto.

What helped, solution:

Necessary to replace a resistor:

- R216 (30.1kOm) pin 4 IC39 for NEW PRODUCTION

- R8 (or R9 ... poor quality serv manual ) pin 4 IC2 for OLD PRODUCTION

by 28-40kOm (find a suitable for your case).


Replacing this resistor shifts the overall "tune". This is what lacking in order to properly tune PolySix.


Because if you reach the correct overall "tune" At least one "voice", but for this you have to turn out VR1, VR15 in position close to the extreme ..... you just can not adjust tune scale in PolySix.


I hope it will help you, because it helped me and to those who said it to me (huge thanks to him!) If you're already tired tune PolySix, then I am sure that you will quickly learn what is written here and already well will know in which direction and how much you need to move the overall "tune" through replacement resistor R216.


I apologize for my imperfect English. I hope you understand what I wrote.

Re: [PolySix] Tuning Issue--the opto is replaced

2014-01-08 by <josh.nursing@gmail.com>

Well done, Michael, and thanks for sharing. One day it will be good to collect all the info about how to diagnose and repair a Polysix in one wiki or FAQ to help others on their way.


Yash