Korg Poly800/EX800 Users

hello everybody!

seems like my poly 800 mk1 is stuck in sequencer mode. I´ve already
checkt +5V and -5V, exactly adjusted.

anyone any further idea?

thanks

moe

--- In korgpolyex@yahoogroups.com, "m.sislack" <m.sislack@...> wrote:

>
> hello everybody!
>
> seems like my poly 800 mk1 is stuck in sequencer mode. I´ve already
> checkt +5V and -5V, exactly adjusted.
>
> anyone any further idea?

Whenever any of my devices seem to be stuck in a particular mode the
cause is always the button to access that mode being stuck partially
depressed enough to engage the circuit. Never had it happen to my Poly
800 but then I finally just acquired a working Poly 800 a few days ago.

>
> thanks
>
> moe
>

When you say "sequencer mode", do you mean the Poly always jumps into
playing the sequence or does it jump into sequencer edit mode?

If you mean it is dropping into sequencer edit mode, then you must
have the sequencer enable switch on the back set to enable (and most
likely the sequencer play button is stuck down too). To prove this,
set the sequencer switch on the back to disable. Then power off and
back on the Poly. Then see if the sequencer starts playing the
sequence or does it just behave normally but you are unable to play a
sequence?

Mike.

--- In korgpolyex@yahoogroups.com, "m.sislack" <m.sislack@...> wrote:
>
> hello everybody!
>
> seems like my poly 800 mk1 is stuck in sequencer mode. I´ve already
> checkt +5V and -5V, exactly adjusted.
>
> anyone any further idea?
>
> thanks
>
> moe
>

--- In korgpolyex@yahoogroups.com, "korgpolyex800"
<korgpolyex800@...> wrote:

>
> When you say "sequencer mode", do you mean the Poly always jumps

into

> playing the sequence or does it jump into sequencer edit mode?
>
> If you mean it is dropping into sequencer edit mode, then you must
> have the sequencer enable switch on the back set to enable (and most
> likely the sequencer play button is stuck down too). To prove this,
> set the sequencer switch on the back to disable. Then power off and
> back on the Poly. Then see if the sequencer starts playing the
> sequence or does it just behave normally but you are unable to play

a

> sequence?
>
> Mike.
>

Hi Mike!

Whn power ist switched on it seems to be in sequencer-edit-mode no
matter if the switch is enable or disable, program-number sais 1.8
but you can´t change it either. When VR1 is turned the display starts
to show weird things an the Poly makes weird noises until the display
tuns into "TAPE"-mode. No change can be made by pressing any buttons.

Moe

If I recall, VR1 is the +5V setting - which means you ought not to be
twiddling with it. Instead, make sure you set the rail to +5V and
leave it alone after that.

How can you see program 11 if the keyboard is in sequencer edit mode?

Is there any sign of moisture corroding anything on any of the boards?

Is there any corrosion near the backup battery (if it is installed on
the main board)?

Mike.

--- In korgpolyex@yahoogroups.com, "m.sislack" <m.sislack@...> wrote:
>
> --- In korgpolyex@yahoogroups.com, "korgpolyex800"
> <korgpolyex800@> wrote:
> >
> > When you say "sequencer mode", do you mean the Poly always jumps
> into
> > playing the sequence or does it jump into sequencer edit mode?
> >
> > If you mean it is dropping into sequencer edit mode, then you must
> > have the sequencer enable switch on the back set to enable (and most
> > likely the sequencer play button is stuck down too). To prove this,
> > set the sequencer switch on the back to disable. Then power off and
> > back on the Poly. Then see if the sequencer starts playing the
> > sequence or does it just behave normally but you are unable to play
> a
> > sequence?
> >
> > Mike.
> >
>
> Hi Mike!
>
> Whn power ist switched on it seems to be in sequencer-edit-mode no
> matter if the switch is enable or disable, program-number sais 1.8
> but you can´t change it either. When VR1 is turned the display starts
> to show weird things an the Poly makes weird noises until the display
> tuns into "TAPE"-mode. No change can be made by pressing any buttons.
>
> Moe
>

--- In korgpolyex@yahoogroups.com, "korgpolyex800"
<korgpolyex800@...> wrote:

>
> If I recall, VR1 is the +5V setting - which means you ought not to

be

> twiddling with it. Instead, make sure you set the rail to +5V and
> leave it alone after that.
>
> How can you see program 11 if the keyboard is in sequencer edit

mode?

>
> Is there any sign of moisture corroding anything on any of the

boards?

>
> Is there any corrosion near the backup battery (if it is installed

on

> the main board)?
>
> Mike.
>

Yes, VR1 is the +5V setting and i have already set it back to +5V. I
don´t know if it is actually the program number that is shown but the
left display sais "1.8". There are no visible signs of corrosion but
it seems someone in the past had to repair to traces by soldering a
thin wire on the board. It´s still the model wihout any backup
battery.

moe

1.8 in the left display is not sequencer edit mode, that's for sure.

If you turn the keyboard you should get 11 P. Then, if you switched to
sequencer edit mode the display would change to 11 50 01.

So it seems you have a more serious problem than just stuck switches.

Does the keyboard make sounds when you hit keys? If yes, do all of the
keys work, or just some of them? Which ones?

Mike.

--- In korgpolyex@yahoogroups.com, "m.sislack" <m.sislack@...> wrote:
>
> --- In korgpolyex@yahoogroups.com, "korgpolyex800"
> <korgpolyex800@> wrote:
> >
> > If I recall, VR1 is the +5V setting - which means you ought not to
> be
> > twiddling with it. Instead, make sure you set the rail to +5V and
> > leave it alone after that.
> >
> > How can you see program 11 if the keyboard is in sequencer edit
> mode?
> >
> > Is there any sign of moisture corroding anything on any of the
> boards?
> >
> > Is there any corrosion near the backup battery (if it is installed
> on
> > the main board)?
> >
> > Mike.
> >
> Yes, VR1 is the +5V setting and i have already set it back to +5V. I
> don´t know if it is actually the program number that is shown but the
> left display sais "1.8". There are no visible signs of corrosion but
> it seems someone in the past had to repair to traces by soldering a
> thin wire on the board. It´s still the model wihout any backup
> battery.
>
> moe
>

--- In korgpolyex@yahoogroups.com, "korgpolyex800" <korgpolyex800@...>
wrote:

>
> 1.8 in the left display is not sequencer edit mode, that's for sure.
>
> If you turn the keyboard you should get 11 P. Then, if you switched to
> sequencer edit mode the display would change to 11 50 01.
>
> So it seems you have a more serious problem than just stuck switches.
>
> Does the keyboard make sounds when you hit keys? If yes, do all of the
> keys work, or just some of them? Which ones?
>
> Mike.
>

Hello Mike!

In deed it seems to be a more serious problem. Ehen switches on, in the
display is shown "1.8 50 01", but theres no reaction to key-hits or
pressed buttons, not even to the switches on the back. Only when VR1 is
turned, the machine awakes and starts to make weird noises like
uncontrolled key-hits and noise with cut off-modulations. This is why I
wonder if the problem might be caused by any dead transistors Q1, Q2 or
maybe Q18.

moe

Hi Moe,

How did you go working on your Poly with the weird display problem?
Reason I ask is that I pulled out of storage my most beat up Poly 800
and discovered that it has a very similar problem.

In my case, when I power up the Poly the display immediately shows "7-
P". So it looks like the 7 button is stuck down. Also, if I set the
sequencer enable switch on the back then power up the keyboard it also
displays "11 50 01".

So I think I have a problem that is very similar to yours. I know that
the 7 switch is not stuck because I swapped out the main board into my
EX-800 and it still does the same thing.

So over the next week I will be looking closely at that main board.

Does anyone else have any history with the display behaving weird in a
similar way?

Mike.

--- In korgpolyex@yahoogroups.com, "m.sislack" <m.sislack@...> wrote:
>
> --- In korgpolyex@yahoogroups.com, "korgpolyex800" <korgpolyex800@>
> wrote:
> >
> > 1.8 in the left display is not sequencer edit mode, that's for sure.
> >
> > If you turn the keyboard you should get 11 P. Then, if you switched to
> > sequencer edit mode the display would change to 11 50 01.
> >
> > So it seems you have a more serious problem than just stuck switches.
> >
> > Does the keyboard make sounds when you hit keys? If yes, do all of the
> > keys work, or just some of them? Which ones?
> >
> > Mike.
> >
> Hello Mike!
>
> In deed it seems to be a more serious problem. Ehen switches on, in the
> display is shown "1.8 50 01", but theres no reaction to key-hits or
> pressed buttons, not even to the switches on the back. Only when VR1 is
> turned, the machine awakes and starts to make weird noises like
> uncontrolled key-hits and noise with cut off-modulations. This is why I
> wonder if the problem might be caused by any dead transistors Q1, Q2 or
> maybe Q18.
>
> moe
>

Hi mike :)

I put the project aside for a while. I again made sure, that I had
the right voltages in the circuit but since I´m not a so much
experienced technician, I could not get any closer to a solution.
Maybe I have to consider a malfunction of the cpu at last. I don´t
know... a service-manual might be helpful ;/

moe

--- In korgpolyex@yahoogroups.com, "korgpolyex800"
<korgpolyex800@...> wrote:

>
> Hi Moe,
>
> How did you go working on your Poly with the weird display problem?
> Reason I ask is that I pulled out of storage my most beat up Poly

800

> and discovered that it has a very similar problem.
>
> In my case, when I power up the Poly the display immediately

shows "7-

> P". So it looks like the 7 button is stuck down. Also, if I set the
> sequencer enable switch on the back then power up the keyboard it

also

> displays "11 50 01".
>
> So I think I have a problem that is very similar to yours. I know

that

> the 7 switch is not stuck because I swapped out the main board into

my

> EX-800 and it still does the same thing.
>
> So over the next week I will be looking closely at that main board.
>
> Does anyone else have any history with the display behaving weird

in a

> similar way?
>
> Mike.
>
> --- In korgpolyex@yahoogroups.com, "m.sislack" <m.sislack@> wrote:
> >
> > --- In korgpolyex@yahoogroups.com, "korgpolyex800"

<korgpolyex800@>

> > wrote:
> > >
> > > 1.8 in the left display is not sequencer edit mode, that's for

sure.

> > >
> > > If you turn the keyboard you should get 11 P. Then, if you

switched to

> > > sequencer edit mode the display would change to 11 50 01.
> > >
> > > So it seems you have a more serious problem than just stuck

switches.

> > >
> > > Does the keyboard make sounds when you hit keys? If yes, do all

of the

> > > keys work, or just some of them? Which ones?
> > >
> > > Mike.
> > >
> > Hello Mike!
> >
> > In deed it seems to be a more serious problem. Ehen switches on,

in the

> > display is shown "1.8 50 01", but theres no reaction to key-hits

or

> > pressed buttons, not even to the switches on the back. Only when

VR1 is

> > turned, the machine awakes and starts to make weird noises like
> > uncontrolled key-hits and noise with cut off-modulations. This is

why I

> > wonder if the problem might be caused by any dead transistors Q1,

Q2 or

> > maybe Q18.
> >
> > moe
> >
>

Moe,

I very much doubt the problem will be CPU itself.

Since this last email to you I sent another that told of how I fixed
one of my other Poly 800's that had similar problem to yours.

I found that IC33 had failed on one pin and as a result button 7 was
effectively stuck on. This caused my poly to power up immediately
showing a strange display.

Before I worked out that it was the chip itself, I checked the
keyboards lines, the steering diodes and the DTC's.

Look back for that email because it was quite detailed.

Good luck,

Mike

--- In korgpolyex@yahoogroups.com, "m.sislack" <m.sislack@...> wrote:
>
> Hi mike :)
>
> I put the project aside for a while. I again made sure, that I had
> the right voltages in the circuit but since I´m not a so much
> experienced technician, I could not get any closer to a solution.
> Maybe I have to consider a malfunction of the cpu at last. I don´t
> know... a service-manual might be helpful ;/
>
> moe
>
> --- In korgpolyex@yahoogroups.com, "korgpolyex800"
> <korgpolyex800@> wrote:
> >
> > Hi Moe,
> >
> > How did you go working on your Poly with the weird display problem?
> > Reason I ask is that I pulled out of storage my most beat up Poly
> 800
> > and discovered that it has a very similar problem.
> >
> > In my case, when I power up the Poly the display immediately
> shows "7-
> > P". So it looks like the 7 button is stuck down. Also, if I set the
> > sequencer enable switch on the back then power up the keyboard it
> also
> > displays "11 50 01".
> >
> > So I think I have a problem that is very similar to yours. I know
> that
> > the 7 switch is not stuck because I swapped out the main board into
> my
> > EX-800 and it still does the same thing.
> >
> > So over the next week I will be looking closely at that main board.
> >
> > Does anyone else have any history with the display behaving weird
> in a
> > similar way?
> >
> > Mike.
> >
> > --- In korgpolyex@yahoogroups.com, "m.sislack" <m.sislack@> wrote:
> > >
> > > --- In korgpolyex@yahoogroups.com, "korgpolyex800"
> <korgpolyex800@>
> > > wrote:
> > > >
> > > > 1.8 in the left display is not sequencer edit mode, that's for
> sure.
> > > >
> > > > If you turn the keyboard you should get 11 P. Then, if you
> switched to
> > > > sequencer edit mode the display would change to 11 50 01.
> > > >
> > > > So it seems you have a more serious problem than just stuck
> switches.
> > > >
> > > > Does the keyboard make sounds when you hit keys? If yes, do all
> of the
> > > > keys work, or just some of them? Which ones?
> > > >
> > > > Mike.
> > > >
> > > Hello Mike!
> > >
> > > In deed it seems to be a more serious problem. Ehen switches on,
> in the
> > > display is shown "1.8 50 01", but theres no reaction to key-hits
> or
> > > pressed buttons, not even to the switches on the back. Only when
> VR1 is
> > > turned, the machine awakes and starts to make weird noises like
> > > uncontrolled key-hits and noise with cut off-modulations. This is
> why I
> > > wonder if the problem might be caused by any dead transistors Q1,
> Q2 or
> > > maybe Q18.
> > >
> > > moe
> > >
> >
>

Thank you, Mike, that was helpful for me also. I have almost the same issue: Poly800 frozen right after powering up with "1 50 01" display with no sound and reaction to any buttons or keys. Could you please tell me how to check if the IC33 is broken? Thanks!

Hi Mike,
My poly800 is completely frozen, I cannot say which button or key works or not, none of them respond. I measured voltages on IC33 pins - half of them are 5V, others are 2.5V, no changes when I push buttons.
Thanks!
Andrey

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