Korg Poly800/EX800 Users

> need to add a battery then restore the sound in order to make a fully

--- In korgpolyex@yahoogroups.com, Manu <g.manu@...> wrote:
>
> If it doesn't contain a battery all the default sounds are gone. You
> need to add a battery then restore the sound in order to make a fully
> working Poly sound. Mine was unable to make any sound until I did this.
>
> Manu
>

On Fri, 21 Apr 2006, Rob wrote:

> Well, the Poly-800 I saved from the dumpster is not looking too good
> at the moment! The bad news is that it has no LED read-out of any
> kind, no flashing, nada. The good thing is, is that as I checked the
> V+ at the input I caught it dropping a few volts and suspected some
> kind of life! I proceeded to connect a set of phones to it and lo and
> behold, the unit gave me a real slow, but sweet pitch, amplitude
> and filter sweep, in stereo several seconds after start-up! It all
> swept up to a max and held. The only thing I can do to the sound is
> tune it with the slider and turn it up and down with the volume pot.
> Absolutely nothing else works. (I can affect the res. and cut-off with
> VR's 2 & 3) So obviously the power, amp, filter and oscillator (not
> necessarily in that order!)sections are working fine. Is there a
> secret button combo or power-up trick that would re-initialize this
> thing or is the back-up and sysex "lost"? The lack of display is a bother.
> As you may remember from my previous post, I am a fairly effective
> bench tech and a damn good solderer and I read schematics fine, so
> even if there is something wrong at the component level, I shouldn't
> have any problems doing the fix, as long as someone out there has seen
> this problem before and knows the situation here. Aside from some one
> familiar with this glitch, it will be a stretch. Hopefully it won't be
> a big deal, so if you have an idea, I'll try to raise another Korg
> back from the dead! Otherwise, I have a really huge mono-patch, single
> sweep noise machine.
> I am sure that's why I got this for nothing! But in the words of
> Monty Python...
> "IT"S NOT DEAD YET!!"
>
>
>
>
>

On 21/04/2006, at 1:03 PM, Rob wrote:


> Well, the Poly-800 I saved from the dumpster is not looking too good
> at the moment! The bad news is that it has no LED read-out of any
> kind, no flashing, nada. The good thing is, is that as I checked the
> V+ at the input I caught it dropping a few volts and suspected some
> kind of life! I proceeded to connect a set of phones to it and lo and
> behold, the unit gave me a real slow, but sweet pitch, amplitude
> and filter sweep, in stereo several seconds after start-up! It all
> swept up to a max and held. The only thing I can do to the sound is
> tune it with the slider and turn it up and down with the volume pot.
> Absolutely nothing else works. (I can affect the res. and cut-off with
> VR's 2 & 3) So obviously the power, amp, filter and oscillator (not
> necessarily in that order!)sections are working fine. Is there a
> secret button combo or power-up trick that would re-initialize this
> thing or is the back-up and sysex "lost"? The lack of display is a
> bother.
> As you may remember from my previous post, I am a fairly effective
> bench tech and a damn good solderer and I read schematics fine, so
> even if there is something wrong at the component level, I shouldn't
> have any problems doing the fix, as long as someone out there has seen
> this problem before and knows the situation here. Aside from some one
> familiar with this glitch, it will be a stretch. Hopefully it won't be
> a big deal, so if you have an idea, I'll try to raise another Korg
> back from the dead! Otherwise, I have a really huge mono-patch, single
> sweep noise machine.
> I am sure that's why I got this for nothing! But in the words of
> Monty Python...
> "IT"S NOT DEAD YET!!"
>
>
>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
>
>

--- In korgpolyex@yahoogroups.com, Marcus Wilson <JB@...> wrote:
>
> G'day Rob
>
> Ive now resurrected 2 korgs from dead state, with no display on the
> LED's
>
> it seems from both of mine that the issue was with the +5/-5V
> generation circuit
>
> The second one also had a dead op-amp in the headphone out circuit
> which i managed to get sorted again and both are now happy
>
> To check whether this is the problem with yours, take some readings
> at the joystick for the +5 -5V where the connector plugs in
>
> if these are not showing the appropriate voltages, its a fairly good
> chance that the 3 input transistors have gone bunky, and not
> generating the voltages for the LED circuitry etc
>
> check out Q1 Q3 and Q18 to make sure they are functioning correctly
>
> the schematics for the poly are stored in the archive for this newsgroup
>
> good luck!
>
> Marcus Wilson
>
> On 21/04/2006, at 1:03 PM, Rob wrote:
>
>
> > Well, the Poly-800 I saved from the dumpster is not looking too good
> > at the moment! The bad news is that it has no LED read-out of any
> > kind, no flashing, nada. The good thing is, is that as I checked the
> > V+ at the input I caught it dropping a few volts and suspected some
> > kind of life! I proceeded to connect a set of phones to it and lo and
> > behold, the unit gave me a real slow, but sweet pitch, amplitude
> > and filter sweep, in stereo several seconds after start-up! It all
> > swept up to a max and held. The only thing I can do to the sound is
> > tune it with the slider and turn it up and down with the volume pot.
> > Absolutely nothing else works. (I can affect the res. and cut-off with
> > VR's 2 & 3) So obviously the power, amp, filter and oscillator (not
> > necessarily in that order!)sections are working fine. Is there a
> > secret button combo or power-up trick that would re-initialize this
> > thing or is the back-up and sysex "lost"? The lack of display is a
> > bother.
> > As you may remember from my previous post, I am a fairly effective
> > bench tech and a damn good solderer and I read schematics fine, so
> > even if there is something wrong at the component level, I shouldn't
> > have any problems doing the fix, as long as someone out there has seen
> > this problem before and knows the situation here. Aside from some one
> > familiar with this glitch, it will be a stretch. Hopefully it won't be
> > a big deal, so if you have an idea, I'll try to raise another Korg
> > back from the dead! Otherwise, I have a really huge mono-patch, single
> > sweep noise machine.
> > I am sure that's why I got this for nothing! But in the words of
> > Monty Python...
> > "IT"S NOT DEAD YET!!"
> >
> >
> >
> >
> >
> >
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
> >
> >
> >
>

--- In korgpolyex@yahoogroups.com, "Rob" <r.bowe@...> wrote:
>
> Well, the Poly-800 I saved from the dumpster is not looking too good
> at the moment! The bad news is that it has no LED read-out of any
> kind, no flashing, nada. The good thing is, is that as I checked the
> V+ at the input I caught it dropping a few volts and suspected some
> kind of life! I proceeded to connect a set of phones to it and lo and
> behold, the unit gave me a real slow, but sweet pitch, amplitude
> and filter sweep, in stereo several seconds after start-up! It all
> swept up to a max and held. The only thing I can do to the sound is
> tune it with the slider and turn it up and down with the volume pot.
> Absolutely nothing else works. (I can affect the res. and cut-off with
> VR's 2 & 3) So obviously the power, amp, filter and oscillator (not
> necessarily in that order!)sections are working fine. Is there a
> secret button combo or power-up trick that would re-initialize this
> thing or is the back-up and sysex "lost"? The lack of display is a
bother.
> As you may remember from my previous post, I am a fairly effective
> bench tech and a damn good solderer and I read schematics fine, so
> even if there is something wrong at the component level, I shouldn't
> have any problems doing the fix, as long as someone out there has seen
> this problem before and knows the situation here. Aside from some one
> familiar with this glitch, it will be a stretch. Hopefully it won't be
> a big deal, so if you have an idea, I'll try to raise another Korg
> back from the dead! Otherwise, I have a really huge mono-patch, single
> sweep noise machine.
> I am sure that's why I got this for nothing! But in the words of
> Monty Python...
> "IT"S NOT DEAD YET!!"
>

I've got exactly the same problem!!!

got my poly800 mkI 2nd hand, LED display/keys not working, the only
thing it gives is a slow sweep from sub bass to high freq noise a few
secs after turning it on, then stays making noise until i turn it off.
chorus, filters and oscillators hence work.

Any ideas?

When powered the IC's all seem to have a voltage across them apart
from the LED IC. could it be a broken IC or (hopefully) something in
the +-5V power circuit not giving the board proper juice? the voltage
regulators maybe?

It's not mkII so it doesn't have internal battery.

No signs of leaked caps or cold solder joints or physical damage...
Tested with both batteries and 9V adapter

THANKS!!

Jouni

--- In korgpolyex@yahoogro ups.com, "Rob" <r.bowe@...> wrote:
>
> Well, the Poly-800 I saved from the dumpster is not looking too good
> at the moment! The bad news is that it has no LED read-out of any
> kind, no flashing, nada. The good thing is, is that as I checked the
> V+ at the input I caught it dropping a few volts and suspected some
> kind of life! I proceeded to connect a set of phones to it and lo and
> behold, the unit gave me a real slow, but sweet pitch, amplitude
> and filter sweep, in stereo several seconds after start-up! It all
> swept up to a max and held. The only thing I can do to the sound is
> tune it with the slider and turn it up and down with the volume pot.
> Absolutely nothing else works. (I can affect the res. and cut-off with
> VR's 2 & 3) So obviously the power, amp, filter and oscillator (not
> necessarily in that order!)sections are working fine. Is there a
> secret button combo or power-up trick that would re-initialize this
> thing or is the back-up and sysex "lost"? The lack of display is a
bother.
> As you may remember from my previous post, I am a fairly effective
> bench tech and a damn good solderer and I read schematics fine, so
> even if there is something wrong at the component level, I shouldn't
> have any problems doing the fix, as long as someone out there has seen
> this problem before and knows the situation here. Aside from some one
> familiar with this glitch, it will be a stretch. Hopefully it won't be
> a big deal, so if you have an idea, I'll try to raise another Korg
> back from the dead! Otherwise, I have a really huge mono-patch, single
> sweep noise machine.
> I am sure that's why I got this for nothing! But in the words of
> Monty Python...
> "IT"S NOT DEAD YET!!"
>

Finding fabulous fares is fun.
Let Yahoo! FareChase search your favorite travel sites to find flight and hotel bargains.

>
> If you have an oscilloscope or multimeter then download the

>
> If you have an oscilloscope then you can check the waveforms

>
> Disclaimer: Just be very careful poking around because you don't

>
> Regardless of the condition of the display chips, the display won't

>
> Let us know what you find.
>
> Mike.
>
> dharmaone1977 <dharmaone1977@...> wrote:

>
> got my poly800 mkI 2nd hand, LED display/keys not working, the only
> thing it gives is a slow sweep from sub bass to high freq noise a few
> secs after turning it on, then stays making noise until i turn it off.
> chorus, filters and oscillators hence work.
>
> Any ideas?
>
> When powered the IC's all seem to have a voltage across them apart
> from the LED IC. could it be a broken IC or (hopefully) something in
> the +-5V power circuit not giving the board proper juice? the voltage
> regulators maybe?
>
> It's not mkII so it doesn't have internal battery.
>
> No signs of leaked caps or cold solder joints or physical damage...
> Tested with both batteries and 9V adapter
>
> THANKS!!
>
> Jouni
>
> --- In korgpolyex@yahoogroups.com, "Rob" <r.bowe@> wrote:
> >
> > Well, the Poly-800 I saved from the dumpster is not looking too good
> > at the moment! The bad news is that it has no LED read-out of any
> > kind, no flashing, nada. The good thing is, is that as I checked the
> > V+ at the input I caught it dropping a few volts and suspected some
> > kind of life! I proceeded to connect a set of phones to it and lo and
> > behold, the unit gave me a real slow, but sweet pitch, amplitude
> > and filter sweep, in stereo several seconds after start-up! It all
> > swept up to a max and held. The only thing I can do to the sound is
> > tune it with the slider and turn it up and down with the volume pot.
> > Absolutely nothing else works. (I can affect the res. and cut-off

> > VR's 2 & 3) So obviously the power, amp, filter and oscillator (not
> > necessarily in that order!)sections are working fine. Is there a
> > secret button combo or power-up trick that would re-initialize this
> > thing or is the back-up and sysex "lost"? The lack of display is a
> bother.
> > As you may remember from my previous post, I am a fairly effective
> > bench tech and a damn good solderer and I read schematics fine, so
> > even if there is something wrong at the component level, I shouldn't
> > have any problems doing the fix, as long as someone out there has

> > this problem before and knows the situation here. Aside from some one
> > familiar with this glitch, it will be a stretch. Hopefully it

> > a big deal, so if you have an idea, I'll try to raise another Korg
> > back from the dead! Otherwise, I have a really huge mono-patch,

> > sweep noise machine.
> > I am sure that's why I got this for nothing! But in the words of
> > Monty Python...
> > "IT"S NOT DEAD YET!!"
> >
>
>
>
>
>
>
> ---------------------------------
> Finding fabulous fares is fun.
> Let Yahoo! FareChase search your favorite travel sites to find

>

We won't tell. Get more on shows you hate to love
(and love to hate): Yahoo! TV's Guilty Pleasures list.

>
> If you have an oscilloscope or multimeter then download the

>
> If you have an oscilloscope then you can check the waveforms

>
> Disclaimer: Just be very careful poking around because you don't

>
> Regardless of the condition of the display chips, the display won't

>
> Let us know what you find.
>
> Mike.
>
> dharmaone1977 <dharmaone1977@...>

>
> got my poly800 mkI 2nd hand, LED display/keys not working, the only
> thing it gives is a slow sweep from sub bass to high freq noise a

> secs after turning it on, then stays making noise until i turn it

> chorus, filters and oscillators hence work.
>
> Any ideas?
>
> When powered the IC's all seem to have a voltage across them apart
> from the LED IC. could it be a broken IC or (hopefully) something

> the +-5V power circuit not giving the board proper juice? the

> regulators maybe?
>
> It's not mkII so it doesn't have internal battery.
>
> No signs of leaked caps or cold solder joints or physical damage...
> Tested with both batteries and 9V adapter
>
> THANKS!!
>
> Jouni
>
> --- In korgpolyex@yahoogroups.com, "Rob" <r.bowe@> wrote:
> >
> > Well, the Poly-800 I saved from the dumpster is not looking too

> > at the moment! The bad news is that it has no LED read-out of any
> > kind, no flashing, nada. The good thing is, is that as I checked

> > V+ at the input I caught it dropping a few volts and suspected

> > kind of life! I proceeded to connect a set of phones to it and

> > behold, the unit gave me a real slow, but sweet pitch, amplitude
> > and filter sweep, in stereo several seconds after start-up! It

> > swept up to a max and held. The only thing I can do to the sound

> > tune it with the slider and turn it up and down with the volume

> > Absolutely nothing else works. (I can affect the res. and cut-

> > VR's 2 & 3) So obviously the power, amp, filter and oscillator

> > necessarily in that order!)sections are working fine. Is there a
> > secret button combo or power-up trick that would re-initialize

> > thing or is the back-up and sysex "lost"? The lack of display is

> bother.
> > As you may remember from my previous post, I am a fairly

> > bench tech and a damn good solderer and I read schematics fine,

> > even if there is something wrong at the component level, I

> > have any problems doing the fix, as long as someone out there

> > this problem before and knows the situation here. Aside from

> > familiar with this glitch, it will be a stretch. Hopefully it

> > a big deal, so if you have an idea, I'll try to raise another

> > back from the dead! Otherwise, I have a really huge mono-patch,

> > sweep noise machine.
> > I am sure that's why I got this for nothing! But in the words of
> > Monty Python...
> > "IT"S NOT DEAD YET!!"
> >
>
>
>
>
>
>
> ---------------------------------
> Finding fabulous fares is fun.
> Let Yahoo! FareChase search your favorite travel sites to find

>

On 25/02/2007, at 1:38 AM, dharmaone1977 wrote:

> I've checked it with the multimeter now and the pin 9 and 8 on the
> 80C85 show 5v DC.. it doesn't respond to setting any parameters or
> the keys, just stays at this noisy sound after the initial
> filter/frequency sweep
>
> any ideas?
>
> Thanks!
> jouni
>
> --- In korgpolyex@yahoogroups.com, Michael Hawkins
> <korgpolyex800@...> wrote:
> >
> > If you have an oscilloscope or multimeter then download the
> schematics from our group web site and then check the test points
> that are shown on the schematic.
> >
> > If you have an oscilloscope then you can check the waveforms
> precisely. If you only have a multimeter then looking for some
> voltage will do.
> >
> > Disclaimer: Just be very careful poking around because you don't
> want to short anything out and do more damage than you already might
> have.
> >
> > Regardless of the condition of the display chips, the display won't
> show anything at all if the RES6.5 clock is not running. So check for
> voltage on pin 9 of the 80C85. It should read a little above 0 volts.
> >
> > Let us know what you find.
> >
> > Mike.
> >
> > dharmaone1977 <dharmaone1977@...>
> wrote: I've got exactly the same
> problem!!!
> >
> > got my poly800 mkI 2nd hand, LED display/keys not working, the only
> > thing it gives is a slow sweep from sub bass to high freq noise a
> few
> > secs after turning it on, then stays making noise until i turn it
> off.
> > chorus, filters and oscillators hence work.
> >
> > Any ideas?
> >
> > When powered the IC's all seem to have a voltage across them apart
> > from the LED IC. could it be a broken IC or (hopefully) something
> in
> > the +-5V power circuit not giving the board proper juice? the
> voltage
> > regulators maybe?
> >
> > It's not mkII so it doesn't have internal battery.
> >
> > No signs of leaked caps or cold solder joints or physical damage...
> > Tested with both batteries and 9V adapter
> >
> > THANKS!!
> >
> > Jouni
> >
> > --- In korgpolyex@yahoogroups.com, "Rob" <r.bowe@> wrote:
> > >
> > > Well, the Poly-800 I saved from the dumpster is not looking too
> good
> > > at the moment! The bad news is that it has no LED read-out of any
> > > kind, no flashing, nada. The good thing is, is that as I checked
> the
> > > V+ at the input I caught it dropping a few volts and suspected
> some
> > > kind of life! I proceeded to connect a set of phones to it and
> lo and
> > > behold, the unit gave me a real slow, but sweet pitch, amplitude
> > > and filter sweep, in stereo several seconds after start-up! It
> all
> > > swept up to a max and held. The only thing I can do to the sound
> is
> > > tune it with the slider and turn it up and down with the volume
> pot.
> > > Absolutely nothing else works. (I can affect the res. and cut-
> off with
> > > VR's 2 & 3) So obviously the power, amp, filter and oscillator
> (not
> > > necessarily in that order!)sections are working fine. Is there a
> > > secret button combo or power-up trick that would re-initialize
> this
> > > thing or is the back-up and sysex "lost"? The lack of display is
> a
> > bother.
> > > As you may remember from my previous post, I am a fairly
> effective
> > > bench tech and a damn good solderer and I read schematics fine,
> so
> > > even if there is something wrong at the component level, I
> shouldn't
> > > have any problems doing the fix, as long as someone out there
> has seen
> > > this problem before and knows the situation here. Aside from
> some one
> > > familiar with this glitch, it will be a stretch. Hopefully it
> won't be
> > > a big deal, so if you have an idea, I'll try to raise another
> Korg
> > > back from the dead! Otherwise, I have a really huge mono-patch,
> single
> > > sweep noise machine.
> > > I am sure that's why I got this for nothing! But in the words of
> > > Monty Python...
> > > "IT"S NOT DEAD YET!!"
> > >
> >
> >
> >
> >
> >
> >
> > ---------------------------------
> > Finding fabulous fares is fun.
> > Let Yahoo! FareChase search your favorite travel sites to find
> flight and hotel bargains.
> >
>
>
>

--- In korgpolyex@yahoogroups.com, Marcus Wilson <JB@...> wrote:
>
> check at the joystock for the +/- 9V and the +/-5V
> id be thinking its your power input stage to the whole poly
>
> especially if you are not getting the LED display up
>
> best regards,
>
> JB
>
> On 25/02/2007, at 1:38 AM, dharmaone1977 wrote:
>
> > I've checked it with the multimeter now and the pin 9 and 8 on the
> > 80C85 show 5v DC.. it doesn't respond to setting any parameters or
> > the keys, just stays at this noisy sound after the initial
> > filter/frequency sweep
> >
> > any ideas?
> >
> > Thanks!
> > jouni
> >
> > --- In korgpolyex@yahoogroups.com, Michael Hawkins
> > <korgpolyex800@> wrote:
> > >
> > > If you have an oscilloscope or multimeter then download the
> > schematics from our group web site and then check the test points
> > that are shown on the schematic.
> > >
> > > If you have an oscilloscope then you can check the waveforms
> > precisely. If you only have a multimeter then looking for some
> > voltage will do.
> > >
> > > Disclaimer: Just be very careful poking around because you don't
> > want to short anything out and do more damage than you already might
> > have.
> > >
> > > Regardless of the condition of the display chips, the display won't
> > show anything at all if the RES6.5 clock is not running. So check for
> > voltage on pin 9 of the 80C85. It should read a little above 0 volts.
> > >
> > > Let us know what you find.
> > >
> > > Mike.
> > >
> > > dharmaone1977 <dharmaone1977@>
> > wrote: I've got exactly the same
> > problem!!!
> > >
> > > got my poly800 mkI 2nd hand, LED display/keys not working, the only
> > > thing it gives is a slow sweep from sub bass to high freq noise a
> > few
> > > secs after turning it on, then stays making noise until i turn it
> > off.
> > > chorus, filters and oscillators hence work.
> > >
> > > Any ideas?
> > >
> > > When powered the IC's all seem to have a voltage across them apart
> > > from the LED IC. could it be a broken IC or (hopefully) something
> > in
> > > the +-5V power circuit not giving the board proper juice? the
> > voltage
> > > regulators maybe?
> > >
> > > It's not mkII so it doesn't have internal battery.
> > >
> > > No signs of leaked caps or cold solder joints or physical damage...
> > > Tested with both batteries and 9V adapter
> > >
> > > THANKS!!
> > >
> > > Jouni
> > >
> > > --- In korgpolyex@yahoogroups.com, "Rob" <r.bowe@> wrote:
> > > >
> > > > Well, the Poly-800 I saved from the dumpster is not looking too
> > good
> > > > at the moment! The bad news is that it has no LED read-out of any
> > > > kind, no flashing, nada. The good thing is, is that as I checked
> > the
> > > > V+ at the input I caught it dropping a few volts and suspected
> > some
> > > > kind of life! I proceeded to connect a set of phones to it and
> > lo and
> > > > behold, the unit gave me a real slow, but sweet pitch, amplitude
> > > > and filter sweep, in stereo several seconds after start-up! It
> > all
> > > > swept up to a max and held. The only thing I can do to the sound
> > is
> > > > tune it with the slider and turn it up and down with the volume
> > pot.
> > > > Absolutely nothing else works. (I can affect the res. and cut-
> > off with
> > > > VR's 2 & 3) So obviously the power, amp, filter and oscillator
> > (not
> > > > necessarily in that order!)sections are working fine. Is there a
> > > > secret button combo or power-up trick that would re-initialize
> > this
> > > > thing or is the back-up and sysex "lost"? The lack of display is
> > a
> > > bother.
> > > > As you may remember from my previous post, I am a fairly
> > effective
> > > > bench tech and a damn good solderer and I read schematics fine,
> > so
> > > > even if there is something wrong at the component level, I
> > shouldn't
> > > > have any problems doing the fix, as long as someone out there
> > has seen
> > > > this problem before and knows the situation here. Aside from
> > some one
> > > > familiar with this glitch, it will be a stretch. Hopefully it
> > won't be
> > > > a big deal, so if you have an idea, I'll try to raise another
> > Korg
> > > > back from the dead! Otherwise, I have a really huge mono-patch,
> > single
> > > > sweep noise machine.
> > > > I am sure that's why I got this for nothing! But in the words of
> > > > Monty Python...
> > > > "IT"S NOT DEAD YET!!"
> > > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > ---------------------------------
> > > Finding fabulous fares is fun.
> > > Let Yahoo! FareChase search your favorite travel sites to find
> > flight and hotel bargains.
> > >
> >
> >
> >
>

On 26/02/2007, at 11:37 PM, dharmaone1977 wrote:

> +/-5V rails on the joystick seem ok.. in the power stage, the caps
> look fine on the outside.. which ones of the transistors would be
> likely to get whacked? the diodes there would protect them from
> reverse current, right?
>
> on IC IC25 most pins from 20-40 show no voltage.. Neither do the leds
> or the transistor array driving them.. didn't test all of the ICs but
> apart from these they were all showing voltage on the pins
>
> Any ideas?
>
> Thanks!
> Jouni
>
> --- In korgpolyex@yahoogroups.com, Marcus Wilson <JB@...> wrote:
> >
> > check at the joystock for the +/- 9V and the +/-5V
> > id be thinking its your power input stage to the whole poly
> >
> > especially if you are not getting the LED display up
> >
> > best regards,
> >
> > JB
> >
> > On 25/02/2007, at 1:38 AM, dharmaone1977 wrote:
> >
> > > I've checked it with the multimeter now and the pin 9 and 8 on the
> > > 80C85 show 5v DC.. it doesn't respond to setting any parameters or
> > > the keys, just stays at this noisy sound after the initial
> > > filter/frequency sweep
> > >
> > > any ideas?
> > >
> > > Thanks!
> > > jouni
> > >
> > > --- In korgpolyex@yahoogroups.com, Michael Hawkins
> > > <korgpolyex800@> wrote:
> > > >
> > > > If you have an oscilloscope or multimeter then download the
> > > schematics from our group web site and then check the test points
> > > that are shown on the schematic.
> > > >
> > > > If you have an oscilloscope then you can check the waveforms
> > > precisely. If you only have a multimeter then looking for some
> > > voltage will do.
> > > >
> > > > Disclaimer: Just be very careful poking around because you don't
> > > want to short anything out and do more damage than you already
> might
> > > have.
> > > >
> > > > Regardless of the condition of the display chips, the display
> won't
> > > show anything at all if the RES6.5 clock is not running. So
> check for
> > > voltage on pin 9 of the 80C85. It should read a little above 0
> volts.
> > > >
> > > > Let us know what you find.
> > > >
> > > > Mike.
> > > >
> > > > dharmaone1977 <dharmaone1977@>
> > > wrote: I've got exactly the same
> > > problem!!!
> > > >
> > > > got my poly800 mkI 2nd hand, LED display/keys not working,
> the only
> > > > thing it gives is a slow sweep from sub bass to high freq
> noise a
> > > few
> > > > secs after turning it on, then stays making noise until i
> turn it
> > > off.
> > > > chorus, filters and oscillators hence work.
> > > >
> > > > Any ideas?
> > > >
> > > > When powered the IC's all seem to have a voltage across them
> apart
> > > > from the LED IC. could it be a broken IC or (hopefully)
> something
> > > in
> > > > the +-5V power circuit not giving the board proper juice? the
> > > voltage
> > > > regulators maybe?
> > > >
> > > > It's not mkII so it doesn't have internal battery.
> > > >
> > > > No signs of leaked caps or cold solder joints or physical
> damage...
> > > > Tested with both batteries and 9V adapter
> > > >
> > > > THANKS!!
> > > >
> > > > Jouni
> > > >
> > > > --- In korgpolyex@yahoogroups.com, "Rob" <r.bowe@> wrote:
> > > > >
> > > > > Well, the Poly-800 I saved from the dumpster is not looking
> too
> > > good
> > > > > at the moment! The bad news is that it has no LED read-out
> of any
> > > > > kind, no flashing, nada. The good thing is, is that as I
> checked
> > > the
> > > > > V+ at the input I caught it dropping a few volts and suspected
> > > some
> > > > > kind of life! I proceeded to connect a set of phones to it and
> > > lo and
> > > > > behold, the unit gave me a real slow, but sweet pitch,
> amplitude
> > > > > and filter sweep, in stereo several seconds after start-up! It
> > > all
> > > > > swept up to a max and held. The only thing I can do to the
> sound
> > > is
> > > > > tune it with the slider and turn it up and down with the
> volume
> > > pot.
> > > > > Absolutely nothing else works. (I can affect the res. and cut-
> > > off with
> > > > > VR's 2 & 3) So obviously the power, amp, filter and oscillator
> > > (not
> > > > > necessarily in that order!)sections are working fine. Is
> there a
> > > > > secret button combo or power-up trick that would re-initialize
> > > this
> > > > > thing or is the back-up and sysex "lost"? The lack of
> display is
> > > a
> > > > bother.
> > > > > As you may remember from my previous post, I am a fairly
> > > effective
> > > > > bench tech and a damn good solderer and I read schematics
> fine,
> > > so
> > > > > even if there is something wrong at the component level, I
> > > shouldn't
> > > > > have any problems doing the fix, as long as someone out there
> > > has seen
> > > > > this problem before and knows the situation here. Aside from
> > > some one
> > > > > familiar with this glitch, it will be a stretch. Hopefully it
> > > won't be
> > > > > a big deal, so if you have an idea, I'll try to raise another
> > > Korg
> > > > > back from the dead! Otherwise, I have a really huge mono-
> patch,
> > > single
> > > > > sweep noise machine.
> > > > > I am sure that's why I got this for nothing! But in the
> words of
> > > > > Monty Python...
> > > > > "IT"S NOT DEAD YET!!"
> > > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > ---------------------------------
> > > > Finding fabulous fares is fun.
> > > > Let Yahoo! FareChase search your favorite travel sites to find
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> > > >
> > >
> > >
> > >
> >
>
>
>