Synth-DIY Yahoo! Groups Archives

POLY 800 MKII Drifting

2015-10-06 by ian r

Hi, I've searched and haven't found anyone else posting with this problem. Hopefully I'm not just posting in the wrong places.

My poly 800 drifts out of tune over time, often just over the span of a day, and it's usually too far to use the tuning slider on the face of the keyboard to correct it. I have opened it up and tuned it using the trimpots VR1 and VR4, but the problem persists, and opening the keyboard up before each gig is a hassle.

Does anyone have experience with this issue? I don't know enough to judge whether it's a problem with caps, heat, or some other type of shenanigan.

Thanks for reading!

Ian

Re: [korgpolyex] POLY 800 MKII Drifting

2015-10-06 by Daniel Forró

I had the similar problem during one live gig with rock group 32 years ago, and the reason were weak batteries. I had to compensate it by tuning pot, and when it was not enough near the end of the show, by transposing the music. Which was not so comfortable for the person with perfect pitch :-)

Since that I have always used new batteries for each gig, or when using Poly 800 on the stand, always with power supply.

So maybe check everything around power supply, voltage regulators...

Daniel Forro

On Oct 6, 2015, at 2:00 PM, ian r ianpoly800@... [korgpolyex] wrote:

Hi, I've searched and haven't found anyone else posting with this problem. Hopefully I'm not just posting in the wrong places.

My poly 800 drifts out of tune over time, often just over the span of a day, and it's usually too far to use the tuning slider on the face of the keyboard to correct it. I have opened it up and tuned it using the trimpots VR1 and VR4, but the problem persists, and opening the keyboard up before each gig is a hassle.

Does anyone have experience with this issue? I don't know enough to judge whether it's a problem with caps, heat, or some other type of shenanigan.

Thanks for reading!

Ian

Re: [korgpolyex] POLY 800 MKII Drifting

2015-10-06 by ianpoly800@...

thanks for the reply!

thats super frustrating.

I don't think that's it though, I only use a power supply, I checked and it's steady :(

Re: [korgpolyex] POLY 800 MKII Drifting

2015-10-06 by Daniel Forró

If all voltages are OK, then problem is in different part of instrument. Still I'd suppose it's hardware, not software problem.

I'm quite sure more experienced members here would know what can be the cause for this and how to repair.

Daniel Forro

On Oct 6, 2015, at 4:39 PM, ianpoly800@... [korgpolyex] wrote:

thanks for the reply!
thats super frustrating.
I don't think that's it though, I only use a power supply, I checked and it's steady :(

RE: [korgpolyex] POLY 800 MKII Drifting

2015-10-06 by Pieter van Adrichem

Back in the day, I had that same problem. With me, it was a hardware problem, not a very complicated fix as I remember.

________________________________

> To: korgpolyex@yahoogroups.com
> From: korgpolyex@yahoogroups.com
> Date: Tue, 6 Oct 2015 16:45:36 +0900
> Subject: Re: [korgpolyex] POLY 800 MKII Drifting
>
>
>
> If all voltages are OK, then problem is in different part of
> instrument. Still I'd suppose it's hardware, not software problem.
>
> I'm quite sure more experienced members here would know what can be the
> cause for this and how to repair.
>
> Daniel Forro
>
>
> On Oct 6, 2015, at 4:39 PM,
> ianpoly800@...<mailto:ianpoly800@...> [korgpolyex] wrote:
>
>
>
> thanks for the reply!
> thats super frustrating.
> I don't think that's it though, I only use a power supply, I checked
> and it's steady :(
>
>
>

Re: [korgpolyex] POLY 800 MKII Drifting

2015-10-06 by Martin Ator

Clean the tune slider, see if that fixes it.

On Tuesday, 6 October 2015, 9:00, "Pieter van Adrichem pvanadrichem@... [korgpolyex]" <korgpolyex@yahoogroups.com> wrote:

Back in the day, I had that same problem. With me, it was a hardware problem, not a very complicated fix as I remember.

________________________________
> To: korgpolyex@yahoogroups.com
> From: korgpolyex@yahoogroups.com
> Date: Tue, 6 Oct 2015 16:45:36 +0900
> Subject: Re: [korgpolyex] POLY 800 MKII Drifting
>
>
>
> If all voltages are OK, then problem is in different part of
> instrument. Still I'd suppose it's hardware, not software problem.
>
> I'm quite sure more experienced members here would know what can be the
> cause for this and how to repair.
>
> Daniel Forro
>
>
> On Oct 6, 2015, at 4:39 PM,
> ianpoly800@...<mailto:ianpoly800@...> [korgpolyex] wrote:

>
>
>
> thanks for the reply!
> thats super frustrating.
> I don't think that's it though, I only use a power supply, I checked
> and it's steady :(
>
>
>

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

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

Feel free to upload into the files section any sysex dumps and tape dumps of patches that you may have but please discuss (with the entire group) the posting of other files *before* posting them. This helps us to keep redundant information from showing up everywhere and also allows us to constantly improve the format and structure of the documentation. We talk about the HAWK-800 quite a bit but we also discuss and help owners of the original Poly-800 models. So don't be shy if you haven't got the HAWK-800.

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

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Re: [korgpolyex] POLY 800 MKII Drifting

2015-10-06 by Michael Hawkins

Make sure your plug pack/wall wart is correct for your Poly. Sometimes a wall wart may provide higher voltage than it should and this can cause the voltage regulator circuitry to drift enough to cause the master tone generator oscillator to drift too.

I am not worried the amperage. A device only pulls what it needs. But if the plug pack is not the original Korg then check that it is providing nine volts when operating under load (ie: plugged in and Poly is powered on).

/Mike

From: "Martin Ator cyllall@... [korgpolyex]" <korgpolyex@yahoogroups.com>
To: "korgpolyex@yahoogroups.com" <korgpolyex@yahoogroups.com>
Sent: Tuesday, October 6, 2015 11:51 AM
Subject: Re: [korgpolyex] POLY 800 MKII Drifting

Clean the tune slider, see if that fixes it.

On Tuesday, 6 October 2015, 9:00, "Pieter van Adrichem pvanadrichem@... [korgpolyex]" <korgpolyex@yahoogroups.com> wrote:

Back in the day, I had that same problem. With me, it was a hardware problem, not a very complicated fix as I remember.

________________________________
> To: korgpolyex@yahoogroups.com
> From: korgpolyex@yahoogroups.com
> Date: Tue, 6 Oct 2015 16:45:36 +0900
> Subject: Re: [korgpolyex] POLY 800 MKII Drifting
>
>
>
> If all voltages are OK, then problem is in different part of
> instrument. Still I'd suppose it's hardware, not software problem.
>
> I'm quite sure more experienced members here would know what can be the
> cause for this and how to repair.
>
> Daniel Forro
>
>
> On Oct 6, 2015, at 4:39 PM,
> ianpoly800@...<mailto:ianpoly800@...> [korgpolyex] wrote:

>
>
>
> thanks for the reply!
> thats super frustrating.
> I don't think that's it though, I only use a power supply, I checked
> and it's steady :(
>
>
>

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

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

Feel free to upload into the files section any sysex dumps and tape dumps of patches that you may have but please discuss (with the entire group) the posting of other files *before* posting them. This helps us to keep redundant information from showing up everywhere and also allows us to constantly improve the format and structure of the documentation. We talk about the HAWK-800 quite a bit but we also discuss and help owners of the original Poly-800 models. So don't be shy if you haven't got the HAWK-800.

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

Yahoo Groups Links

<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/korgpolyex/

<*> Your email settings:
Individual Email | Traditional

<*> To change settings online go to:
http://groups.yahoo.com/group/korgpolyex/join
(Yahoo! ID required)

<*> To change settings via email:
korgpolyex-digest@yahoogroups.com
korgpolyex-fullfeatured@yahoogroups.com

<*> To unsubscribe from this group, send an email to:
korgpolyex-unsubscribe@yahoogroups.com

<*> Your use of Yahoo Groups is subject to:
https://info.yahoo.com/legal/us/yahoo/utos/terms/

Re: [korgpolyex] POLY 800 MKII Drifting

2015-10-06 by ian r

Will do!! Thanks for the advice everyone.

On Tuesday, October 6, 2015 11:30 AM, "Michael Hawkins korgpolyex800@... [korgpolyex]" <korgpolyex@yahoogroups.com> wrote:

Make sure your plug pack/wall wart is correct for your Poly. Sometimes a wall wart may provide higher voltage than it should and this can cause the voltage regulator circuitry to drift enough to cause the master tone generator oscillator to drift too.

I am not worried the amperage. A device only pulls what it needs. But if the plug pack is not the original Korg then check that it is providing nine volts when operating under load (ie: plugged in and Poly is powered on).

/Mike

From: "Martin Ator cyllall@... [korgpolyex]" <korgpolyex@yahoogroups.com>
To: "korgpolyex@yahoogroups.com" <korgpolyex@yahoogroups.com>
Sent: Tuesday, October 6, 2015 11:51 AM
Subject: Re: [korgpolyex] POLY 800 MKII Drifting

Clean the tune slider, see if that fixes it.

On Tuesday, 6 October 2015, 9:00, "Pieter van Adrichem pvanadrichem@... [korgpolyex]" <korgpolyex@yahoogroups.com> wrote:

Back in the day, I had that same problem. With me, it was a hardware problem, not a very complicated fix as I remember.

________________________________
> To: korgpolyex@yahoogroups.com
> From: korgpolyex@yahoogroups.com
> Date: Tue, 6 Oct 2015 16:45:36 +0900
> Subject: Re: [korgpolyex] POLY 800 MKII Drifting
>
>
>
> If all voltages are OK, then problem is in different part of
> instrument. Still I'd suppose it's hardware, not software problem.
>
> I'm quite sure more experienced members here would know what can be the
> cause for this and how to repair.
>
> Daniel Forro
>
>
> On Oct 6, 2015, at 4:39 PM,
> ianpoly800@...<mailto:ianpoly800@...> [korgpolyex] wrote:

>
>
>
> thanks for the reply!
> thats super frustrating.
> I don't think that's it though, I only use a power supply, I checked
> and it's steady :(
>
>
>

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

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

Feel free to upload into the files section any sysex dumps and tape dumps of patches that you may have but please discuss (with the entire group) the posting of other files *before* posting them. This helps us to keep redundant information from showing up everywhere and also allows us to constantly improve the format and structure of the documentation. We talk about the HAWK-800 quite a bit but we also discuss and help owners of the original Poly-800 models. So don't be shy if you haven't got the HAWK-800.

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

Yahoo Groups Links

<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/korgpolyex/

<*> Your email settings:
Individual Email | Traditional

<*> To change settings online go to:
http://groups.yahoo.com/group/korgpolyex/join
(Yahoo! ID required)

<*> To change settings via email:
korgpolyex-digest@yahoogroups.com
korgpolyex-fullfeatured@yahoogroups.com

<*> To unsubscribe from this group, send an email to:
korgpolyex-unsubscribe@yahoogroups.com

<*> Your use of Yahoo Groups is subject to:
https://info.yahoo.com/legal/us/yahoo/utos/terms/

Re: POLY 800 MKII Drifting

2016-07-24 by ianpoly800@...

I thought I'd update, I never did solve the problem. I ended up bringing the keyboard to a repairman, who thought he'd solved the problem replacing a couple caps, but fast forward $150 in repair hours and the keyboard still drifts. I left it for a week in the same spot and every once in a while would turn it on and watched it fall a few full steps.

The other day I left it on for an hour and a half and it drifted a quarter tone.

Does anyone have any ideas of what I should test in the guts?

Re: [korgpolyex] Re: POLY 800 MKII Drifting

2016-07-24 by Michael Hawkins

Start with your external power supply. Is it is right voltage and does it have a current rating 300mA or higher?

Then check that the power supply rails in the Poly itself are stable. measure at first power on then measure again a few hours later. Are they stable?

/Mike

From: "ianpoly800@... [korgpolyex]" <korgpolyex@yahoogroups.com>
To: korgpolyex@yahoogroups.com
Sent: Sunday, July 24, 2016 5:12 AM
Subject: [korgpolyex] Re: POLY 800 MKII Drifting

I thought I'd update, I never did solve the problem. I ended up bringing the keyboard to a repairman, who thought he'd solved the problem replacing a couple caps, but fast forward $150 in repair hours and the keyboard still drifts. I left it for a week in the same spot and every once in a while would turn it on and watched it fall a few full steps.

The other day I left it on for an hour and a half and it drifted a quarter tone.

Does anyone have any ideas of what I should test in the guts?

Re: [korgpolyex] Re: POLY 800 MKII Drifting

2016-07-30 by ian r

Measuring the circuit on the back of the joystick pcb, the -5V line measures at -4.38V.

On Sunday, July 24, 2016 4:14 PM, "Michael Hawkins korgpolyex800@... [korgpolyex]" <korgpolyex@yahoogroups.com> wrote:

Start with your external power supply. Is it is right voltage and does it have a current rating 300mA or higher?

Then check that the power supply rails in the Poly itself are stable. measure at first power on then measure again a few hours later. Are they stable?

/Mike

From: "ianpoly800@... [korgpolyex]" <korgpolyex@yahoogroups.com>
To: korgpolyex@yahoogroups.com
Sent: Sunday, July 24, 2016 5:12 AM
Subject: [korgpolyex] Re: POLY 800 MKII Drifting

I thought I'd update, I never did solve the problem. I ended up bringing the keyboard to a repairman, who thought he'd solved the problem replacing a couple caps, but fast forward $150 in repair hours and the keyboard still drifts. I left it for a week in the same spot and every once in a while would turn it on and watched it fall a few full steps.

The other day I left it on for an hour and a half and it drifted a quarter tone.

Does anyone have any ideas of what I should test in the guts?

Re: [korgpolyex] Re: POLY 800 MKII Drifting

2016-07-31 by Michael Hawkins

measure again on the main board.

/Mike

From: "ian r ianpoly800@... [korgpolyex]" <korgpolyex@yahoogroups.com>
To: "korgpolyex@yahoogroups.com" <korgpolyex@yahoogroups.com>
Sent: Saturday, July 30, 2016 4:37 PM
Subject: Re: [korgpolyex] Re: POLY 800 MKII Drifting

Measuring the circuit on the back of the joystick pcb, the -5V line measures at -4.38V.

On Sunday, July 24, 2016 4:14 PM, "Michael Hawkins korgpolyex800@... [korgpolyex]" <korgpolyex@yahoogroups.com> wrote:

Start with your external power supply. Is it is right voltage and does it have a current rating 300mA or higher?

Then check that the power supply rails in the Poly itself are stable. measure at first power on then measure again a few hours later. Are they stable?

/Mike

From: "ianpoly800@... [korgpolyex]" <korgpolyex@yahoogroups.com>
To: korgpolyex@yahoogroups.com
Sent: Sunday, July 24, 2016 5:12 AM
Subject: [korgpolyex] Re: POLY 800 MKII Drifting

I thought I'd update, I never did solve the problem. I ended up bringing the keyboard to a repairman, who thought he'd solved the problem replacing a couple caps, but fast forward $150 in repair hours and the keyboard still drifts. I left it for a week in the same spot and every once in a while would turn it on and watched it fall a few full steps.

The other day I left it on for an hour and a half and it drifted a quarter tone.

Does anyone have any ideas of what I should test in the guts?

Re: [korgpolyex] Re: POLY 800 MKII Drifting

2016-08-01 by Donal Finn

I dunno,

Want to cut your losses and sell it to me?

On Sun, Jul 31, 2016 at 8:29 AM, Michael Hawkins korgpolyex800@... [korgpolyex] <korgpolyex@yahoogroups.com> wrote:

measure again on the main board.

/Mike

From: "ian r ianpoly800@... [korgpolyex]" <korgpolyex@yahoogroups.com>
To: "korgpolyex@yahoogroups.com" <korgpolyex@yahoogroups.com>
Sent: Saturday, July 30, 2016 4:37 PM
Subject: Re: [korgpolyex] Re: POLY 800 MKII Drifting

Measuring the circuit on the back of the joystick pcb, the -5V line measures at -4.38V.

On Sunday, July 24, 2016 4:14 PM, "Michael Hawkins korgpolyex800@... [korgpolyex]" <korgpolyex@yahoogroups.com> wrote:

Start with your external power supply. Is it is right voltage and does it have a current rating 300mA or higher?
Then check that the power supply rails in the Poly itself are stable. measure at first power on then measure again a few hours later. Are they stable?

/Mike

From: "ianpoly800@... [korgpolyex]" <korgpolyex@yahoogroups.com>
To: korgpolyex@yahoogroups.com
Sent: Sunday, July 24, 2016 5:12 AM
Subject: [korgpolyex] Re: POLY 800 MKII Drifting

I thought I'd update, I never did solve the problem. I ended up bringing the keyboard to a repairman, who thought he'd solved the problem replacing a couple caps, but fast forward $150 in repair hours and the keyboard still drifts. I left it for a week in the same spot and every once in a while would turn it on and watched it fall a few full steps.

The other day I left it on for an hour and a half and it drifted a quarter tone.

Does anyone have any ideas of what I should test in the guts?

Re: [korgpolyex] Re: POLY 800 MKII Drifting

2016-08-07 by ian r

Haha, not really, I like the sound too much. I'll measure the main board again.

I was hoping that if I eventually fixed the machine I'd get to install a hawk mod, and was toying with the idea of installing the mod and hoping it fixed my problem.

I'm thinking now that that would be a dumb gamble.

Ian

On Sunday, July 31, 2016 9:07 PM, "Donal Finn terrible.dee@... [korgpolyex]" <korgpolyex@yahoogroups.com> wrote:

I dunno,

Want to cut your losses and sell it to me?

On Sun, Jul 31, 2016 at 8:29 AM, Michael Hawkins korgpolyex800@... [korgpolyex] <korgpolyex@yahoogroups.com> wrote:

measure again on the main board.

/Mike

From: "ian r ianpoly800@... [korgpolyex]" <korgpolyex@yahoogroups.com>
To: "korgpolyex@yahoogroups.com" <korgpolyex@yahoogroups.com>
Sent: Saturday, July 30, 2016 4:37 PM
Subject: Re: [korgpolyex] Re: POLY 800 MKII Drifting

Measuring the circuit on the back of the joystick pcb, the -5V line measures at -4.38V.

On Sunday, July 24, 2016 4:14 PM, "Michael Hawkins korgpolyex800@... [korgpolyex]" <korgpolyex@yahoogroups.com> wrote:

Start with your external power supply. Is it is right voltage and does it have a current rating 300mA or higher?
Then check that the power supply rails in the Poly itself are stable. measure at first power on then measure again a few hours later. Are they stable?

/Mike

From: "ianpoly800@... [korgpolyex]" <korgpolyex@yahoogroups.com>
To: korgpolyex@yahoogroups.com
Sent: Sunday, July 24, 2016 5:12 AM
Subject: [korgpolyex] Re: POLY 800 MKII Drifting

I thought I'd update, I never did solve the problem. I ended up bringing the keyboard to a repairman, who thought he'd solved the problem replacing a couple caps, but fast forward $150 in repair hours and the keyboard still drifts. I left it for a week in the same spot and every once in a while would turn it on and watched it fall a few full steps.

The other day I left it on for an hour and a half and it drifted a quarter tone.

Does anyone have any ideas of what I should test in the guts?

Re: [korgpolyex] Re: POLY 800 MKII Drifting

2016-08-09 by Michael Hawkins

You definitely want to get everything working first before doing the HAWK mod. The HAWK mod generally won't fix anything and if you already have problems, far better to sort them out first before going in there again with the modding.

/Mike

From: "ian r ianpoly800@... [korgpolyex]" <korgpolyex@yahoogroups.com>
To: "korgpolyex@yahoogroups.com" <korgpolyex@yahoogroups.com>
Sent: Sunday, August 7, 2016 5:14 PM
Subject: Re: [korgpolyex] Re: POLY 800 MKII Drifting

Haha, not really, I like the sound too much. I'll measure the main board again.

I was hoping that if I eventually fixed the machine I'd get to install a hawk mod, and was toying with the idea of installing the mod and hoping it fixed my problem.

I'm thinking now that that would be a dumb gamble.

Ian

On Sunday, July 31, 2016 9:07 PM, "Donal Finn terrible.dee@... [korgpolyex]" <korgpolyex@yahoogroups.com> wrote:

I dunno,

Want to cut your losses and sell it to me?

On Sun, Jul 31, 2016 at 8:29 AM, Michael Hawkins korgpolyex800@... [korgpolyex] <korgpolyex@yahoogroups.com> wrote:

measure again on the main board.

/Mike

From: "ian r ianpoly800@... [korgpolyex]" <korgpolyex@yahoogroups.com>
To: "korgpolyex@yahoogroups.com" <korgpolyex@yahoogroups.com>
Sent: Saturday, July 30, 2016 4:37 PM
Subject: Re: [korgpolyex] Re: POLY 800 MKII Drifting

Measuring the circuit on the back of the joystick pcb, the -5V line measures at -4.38V.

On Sunday, July 24, 2016 4:14 PM, "Michael Hawkins korgpolyex800@... [korgpolyex]" <korgpolyex@yahoogroups.com> wrote:

Start with your external power supply. Is it is right voltage and does it have a current rating 300mA or higher?
Then check that the power supply rails in the Poly itself are stable. measure at first power on then measure again a few hours later. Are they stable?

/Mike

From: "ianpoly800@... [korgpolyex]" <korgpolyex@yahoogroups.com>
To: korgpolyex@yahoogroups.com
Sent: Sunday, July 24, 2016 5:12 AM
Subject: [korgpolyex] Re: POLY 800 MKII Drifting

I thought I'd update, I never did solve the problem. I ended up bringing the keyboard to a repairman, who thought he'd solved the problem replacing a couple caps, but fast forward $150 in repair hours and the keyboard still drifts. I left it for a week in the same spot and every once in a while would turn it on and watched it fall a few full steps.

The other day I left it on for an hour and a half and it drifted a quarter tone.

Does anyone have any ideas of what I should test in the guts?