Korg Poly800/EX800 Users

>
> Hey guys, 
> I was working with my MK 1 this afternoon. I have this multi socket power supply ( ) and while inserting my Phones jacket, The two metal parts of the cable and the power supply hit eachother. Now the LED's don't light up and it doesn't play sound when powering up.
> 
> Does the poly 800 have some sort of fuse or something? Is there anything I can check to see if it's been burned. I tried finding schematics, but they're so low reoslution, that I can't make anything of it. 
> 
> Can someone please send me in the right direction? :( I've only had this keyboard for a month and I'm in love with it. It can't be broken :(
>

 From: kjelle.vergauwe <bobsrampenbedrijf@...>
To: korgpolyex@yahoogroups.com 
Sent: Saturday, 28 July 2012, 16:10
Subject: [korgpolyex] Poly 800 MK 1 Short circuit
 

  
Hey guys, 
I was working with my MK 1 this afternoon. I have this multi socket power supply ( ) and while inserting my Phones jacket, The two metal parts of the cable and the power supply hit eachother. Now the LED's don't light up and it doesn't play sound when powering up.

Does the poly 800 have some sort of fuse or something? Is there anything I can check to see if it's been burned. I tried finding schematics, but they're so low reoslution, that I can't make anything of it. 

Can someone please send me in the right direction? :( I've only had this keyboard for a month and I'm in love with it. It can't be broken :(

>
> Hey guys, 
> I was working with my MK 1 this afternoon. I have this multi socket power supply ( ) and while inserting my Phones jacket, The two metal parts of the cable and the power supply hit eachother. Now the LED's don't light up and it doesn't play sound when powering up.
> 
> Does the poly 800 have some sort of fuse or something? Is there anything I can check to see if it's been burned. I tried finding schematics, but they're so low reoslution, that I can't make anything of it. 
> 
> Can someone please send me in the right direction? :( I've only had this keyboard for a month and I'm in love with it. It can't be broken :(
>

>
> 
> OHHHHH!!!
> 
> You have one of those "+" plugs on the end of your powersupply output line I bet.. and one of the "legs" of that + plug (with the different sized tip/sleeve connectors) rubbed up against your headphones plug while inserting/removing it in your headphones port/jack.
> 
> Is this what happened??
> 
> -Blaine
>  
> --- In korgpolyex@yahoogroups.com, "kjelle.vergauwe" <bobsrampenbedrijf@> wrote:
> >
> > Hey guys, 
> > I was working with my MK 1 this afternoon. I have this multi socket power supply ( ) and while inserting my Phones jacket, The two metal parts of the cable and the power supply hit eachother. Now the LED's don't light up and it doesn't play sound when powering up.
> > 
> > Does the poly 800 have some sort of fuse or something? Is there anything I can check to see if it's been burned. I tried finding schematics, but they're so low reoslution, that I can't make anything of it. 
> > 
> > Can someone please send me in the right direction? :( I've only had this keyboard for a month and I'm in love with it. It can't be broken :(
> >
>

>
> Yes!
> That's exactly what happend. But the Poly 800 was turned on, and the 1/4" jack that hit the  power supply tip was connected to the line-in of my laptop. The korg's display went out and I haven't been able to turn it back on. Neither with the power supply i was using, or any other. 
> 
> I took some pictures of the circuit board, but nothing seems 'burned' or wrong...
> 
> PS I know connector CN9A  is out of his socket, I did this to give a better view.
> 
> Circuit board:
> 
> http://dl.dropbox.com/u/7760238/poly%20800/foto%201.JPG
> 
> http://dl.dropbox.com/u/7760238/poly%20800/foto%202.JPG
> 
> http://dl.dropbox.com/u/7760238/poly%20800/foto%203.JPG
> http://dl.dropbox.com/u/7760238/poly%20800/foto%204.JPG
> http://dl.dropbox.com/u/7760238/poly%20800/foto%205.JPG
> 
> Power supply :
> 
> http://dl.dropbox.com/u/7760238/poly%20800/foto.JPG
> 
> 
> --- In korgpolyex@yahoogroups.com, "bimmerfan222" <bperkins211@> wrote:
> >
> > 
> > OHHHHH!!!
> > 
> > You have one of those "+" plugs on the end of your powersupply output line I bet.. and one of the "legs" of that + plug (with the different sized tip/sleeve connectors) rubbed up against your headphones plug while inserting/removing it in your headphones port/jack.
> > 
> > Is this what happened??
> > 
> > -Blaine
> >  
> > --- In korgpolyex@yahoogroups.com, "kjelle.vergauwe" <bobsrampenbedrijf@> wrote:
> > >
> > > Hey guys, 
> > > I was working with my MK 1 this afternoon. I have this multi socket power supply ( ) and while inserting my Phones jacket, The two metal parts of the cable and the power supply hit eachother. Now the LED's don't light up and it doesn't play sound when powering up.
> > > 
> > > Does the poly 800 have some sort of fuse or something? Is there anything I can check to see if it's been burned. I tried finding schematics, but they're so low reoslution, that I can't make anything of it. 
> > > 
> > > Can someone please send me in the right direction? :( I've only had this keyboard for a month and I'm in love with it. It can't be broken :(
> > >
> >
>

>
> Yes!
> That's exactly what happend. But the Poly 800 was turned on, and the 1/4" jack that hit the  power supply tip was connected to the line-in of my laptop. The korg's display went out and I haven't been able to turn it back on. Neither with the power supply i was using, or any other. 
> 
> I took some pictures of the circuit board, but nothing seems 'burned' or wrong...
> 
> PS I know connector CN9A  is out of his socket, I did this to give a better view.
> 
> Circuit board:
> 
> http://dl.dropbox.com/u/7760238/poly%20800/foto%201.JPG
> 
> http://dl.dropbox.com/u/7760238/poly%20800/foto%202.JPG
> 
> http://dl.dropbox.com/u/7760238/poly%20800/foto%203.JPG
> http://dl.dropbox.com/u/7760238/poly%20800/foto%204.JPG
> http://dl.dropbox.com/u/7760238/poly%20800/foto%205.JPG
> 
> Power supply :
> 
> http://dl.dropbox.com/u/7760238/poly%20800/foto.JPG
> 
> 
> --- In korgpolyex@yahoogroups.com, "bimmerfan222" <bperkins211@> wrote:
> >
> > 
> > OHHHHH!!!
> > 
> > You have one of those "+" plugs on the end of your powersupply output line I bet.. and one of the "legs" of that + plug (with the different sized tip/sleeve connectors) rubbed up against your headphones plug while inserting/removing it in your headphones port/jack.
> > 
> > Is this what happened??
> > 
> > -Blaine
> > 
> > --- In korgpolyex@yahoogroups.com, "kjelle.vergauwe" <bobsrampenbedrijf@> wrote:
> > >
> > > Hey guys, 
> > > I was working with my MK 1 this afternoon. I have this multi socket power supply ( ) and while inserting my Phones jacket, The two metal parts of the cable and the power supply hit eachother. Now the LED's don't light up and it doesn't play sound when powering up.
> > > 
> > > Does the poly 800 have some sort of fuse or something? Is there anything I can check to see if it's been burned. I tried finding schematics, but they're so low reoslution, that I can't make anything of it. 
> > > 
> > > Can someone please send me in the right direction? :( I've only had this keyboard for a month and I'm in love with it. It can't be broken :(
> > >
> >
>

>
> Does the power supply still work OK?
> And your headphones?
> Do you have any test equipment multimeter etc?
> 
> In foto 4 it shows connector CN9A. 2 components to the right is a diode. Check this still conducts one way but not the other.
> 
> If you plug the power supply in (if it still works) and your headphones, can you hear a pop sound in your headphones when you turn the volume knob to switch the poly on, any hissing etc?
> 
> 
> 
> ________________________________
>  From: kjelle.vergauwe <bobsrampenbedrijf@...>
> To: korgpolyex@yahoogroups.com 
> Sent: Saturday, 28 July 2012, 18:09
> Subject: [korgpolyex] Re: Poly 800 MK 1 Short circuit
>  
> 
> Â  
> 2 last pictures are switched up.
> 
> Haven't tried batteries yet. Don't have batteries right now, and it's saturday night over here (no way to get batteries now).
> 
> --- In korgpolyex@yahoogroups.com, "kjelle.vergauwe" <bobsrampenbedrijf@> wrote:
> >
> > Yes!
> > That's exactly what happend. But the Poly 800 was turned on, and the 1/4" jack that hit the  power supply tip was connected to the line-in of my laptop. The korg's display went out and I haven't been able to turn it back on. Neither with the power supply i was using, or any other. 
> > 
> > I took some pictures of the circuit board, but nothing seems 'burned' or wrong...
> > 
> > PS I know connector CN9A  is out of his socket, I did this to give a better view.
> > 
> > Circuit board:
> > 
> > http://dl.dropbox.com/u/7760238/poly%20800/foto%201.JPG
> > 
> > http://dl.dropbox.com/u/7760238/poly%20800/foto%202.JPG
> > 
> > http://dl.dropbox.com/u/7760238/poly%20800/foto%203.JPG
> > http://dl.dropbox.com/u/7760238/poly%20800/foto%204.JPG
> > http://dl.dropbox.com/u/7760238/poly%20800/foto%205.JPG
> > 
> > Power supply :
> > 
> > http://dl.dropbox.com/u/7760238/poly%20800/foto.JPG
> > 
> > 
> > --- In korgpolyex@yahoogroups.com, "bimmerfan222" <bperkins211@> wrote:
> > >
> > > 
> > > OHHHHH!!!
> > > 
> > > You have one of those "+" plugs on the end of your powersupply output line I bet.. and one of the "legs" of that + plug (with the different sized tip/sleeve connectors) rubbed up against your headphones plug while inserting/removing it in your headphones port/jack.
> > > 
> > > Is this what happened??
> > > 
> > > -Blaine
> > > 
> > > --- In korgpolyex@yahoogroups.com, "kjelle.vergauwe" <bobsrampenbedrijf@> wrote:
> > > >
> > > > Hey guys, 
> > > > I was working with my MK 1 this afternoon. I have this multi socket power supply ( ) and while inserting my Phones jacket, The two metal parts of the cable and the power supply hit eachother. Now the LED's don't light up and it doesn't play sound when powering up.
> > > > 
> > > > Does the poly 800 have some sort of fuse or something? Is there anything I can check to see if it's been burned. I tried finding schematics, but they're so low reoslution, that I can't make anything of it. 
> > > > 
> > > > Can someone please send me in the right direction? :( I've only had this keyboard for a month and I'm in love with it. It can't be broken :(
> > > >
> > >
> >
>

>
> Does the power supply still work OK?
> And your headphones?
> Do you have any test equipment multimeter etc?
> 
> In foto 4 it shows connector CN9A. 2 components to the right is a diode. Check this still conducts one way but not the other.
> 
> If you plug the power supply in (if it still works) and your headphones, can you hear a pop sound in your headphones when you turn the volume knob to switch the poly on, any hissing etc?
> 
> 
> 
> ________________________________
>  From: kjelle.vergauwe <bobsrampenbedrijf@...>
> To: korgpolyex@yahoogroups.com 
> Sent: Saturday, 28 July 2012, 18:09
> Subject: [korgpolyex] Re: Poly 800 MK 1 Short circuit
> 
> 
> Â  
> 2 last pictures are switched up.
> 
> Haven't tried batteries yet. Don't have batteries right now, and it's saturday night over here (no way to get batteries now).
> 
> --- In korgpolyex@yahoogroups.com, "kjelle.vergauwe" <bobsrampenbedrijf@> wrote:
> >
> > Yes!
> > That's exactly what happend. But the Poly 800 was turned on, and the 1/4" jack that hit the  power supply tip was connected to the line-in of my laptop. The korg's display went out and I haven't been able to turn it back on. Neither with the power supply i was using, or any other. 
> > 
> > I took some pictures of the circuit board, but nothing seems 'burned' or wrong...
> > 
> > PS I know connector CN9A  is out of his socket, I did this to give a better view.
> > 
> > Circuit board:
> > 
> > http://dl.dropbox.com/u/7760238/poly%20800/foto%201.JPG
> > 
> > http://dl.dropbox.com/u/7760238/poly%20800/foto%202.JPG
> > 
> > http://dl.dropbox.com/u/7760238/poly%20800/foto%203.JPG
> > http://dl.dropbox.com/u/7760238/poly%20800/foto%204.JPG
> > http://dl.dropbox.com/u/7760238/poly%20800/foto%205.JPG
> > 
> > Power supply :
> > 
> > http://dl.dropbox.com/u/7760238/poly%20800/foto.JPG
> > 
> > 
> > --- In korgpolyex@yahoogroups.com, "bimmerfan222" <bperkins211@> wrote:
> > >
> > > 
> > > OHHHHH!!!
> > > 
> > > You have one of those "+" plugs on the end of your powersupply output line I bet.. and one of the "legs" of that + plug (with the different sized tip/sleeve connectors) rubbed up against your headphones plug while inserting/removing it in your headphones port/jack.
> > > 
> > > Is this what happened??
> > > 
> > > -Blaine
> > > 
> > > --- In korgpolyex@yahoogroups.com, "kjelle.vergauwe" <bobsrampenbedrijf@> wrote:
> > > >
> > > > Hey guys, 
> > > > I was working with my MK 1 this afternoon. I have this multi socket power supply ( ) and while inserting my Phones jacket, The two metal parts of the cable and the power supply hit eachother. Now the LED's don't light up and it doesn't play sound when powering up.
> > > > 
> > > > Does the poly 800 have some sort of fuse or something? Is there anything I can check to see if it's been burned. I tried finding schematics, but they're so low reoslution, that I can't make anything of it. 
> > > > 
> > > > Can someone please send me in the right direction? :( I've only had this keyboard for a month and I'm in love with it. It can't be broken :(
> > > >
> > >
> >
>

>
> On 28/07/12 18:33, Martin Ator wrote:
> >
> >
> >
> > If there is no pop and nothing on the display, or any other noises, then
> > probably power isn't getting into the circuits. Any of the parts
> > designed to protect against short circuit in the power circuit could be
> > dead. The diode I told you about is a good candidate to start looking
> > from. I have had to replace one in the past. If you have a diode test
> > you can check this or just see if 9v is getting to the other side of the
> > diode.
> > I think it is the same as a 1N4004 diode.
> 
> http://www.oldcrows.net/~patchell/poly800/poly800.html
> 
> Check the 2SB744 "pre-regulator" regulator, which is in the negative 
> lead from the power socket.
> 
> D2 is just to protect against incorrect polarity.
> 
> -- 
> Gordonjcp MM0YEQ
>

>
> On 28/07/12 18:33, Martin Ator wrote:
> >
> >
> >
> > If there is no pop and nothing on the display, or any other noises, then
> > probably power isn't getting into the circuits. Any of the parts
> > designed to protect against short circuit in the power circuit could be
> > dead. The diode I told you about is a good candidate to start looking
> > from. I have had to replace one in the past. If you have a diode test
> > you can check this or just see if 9v is getting to the other side of the
> > diode.
> > I think it is the same as a 1N4004 diode.
> 
> http://www.oldcrows.net/~patchell/poly800/poly800.html
> 
> Check the 2SB744 "pre-regulator" regulator, which is in the negative 
> lead from the power socket.
> 
> D2 is just to protect against incorrect polarity.
> 
> -- 
> Gordonjcp MM0YEQ
>

>
> OK.Not sure what those readings are. You could try to apply power and see if you can find the 9v after the power socket. Is there a continuity tester on your multimeter? i,e is there a way you can make it beep if there is a short circuit? Some settings depending on the meter, will make a beep if you touch the meter's leads together, so if two parts of a circuit are joined you can trace it easily. First find the negative of the power socket, and then use the positive meter lead to check each side of the diode. If you find the 9v, follow the circuit until it disappears. Sorry if you think that I'm talking to you like a baby, I don't know how much experience you have. You can also identify an IC from the circuit diagram and test if power is getting to it. This might be easier. Try IC24 80C85. Pin 20 is negative/VSS and Pin 40 is Positive/VDD 
> 
> There is a link to some schematics earlier in this message. These ones by Mr Pearce are probably the clearest images around.See if you can find the parts you are checking in real life,here.
> 
> Don't forget the 2SB744 
> 
> 
> 
> 
> ________________________________
>  From: kjelle.vergauwe <bobsrampenbedrijf@...>
> To: korgpolyex@yahoogroups.com 
> Sent: Sunday, 29 July 2012, 10:32
> Subject: [korgpolyex] Re: Poly 800 MK 1 Short circuit
>  
> 
> Â  
> I'm not really good with a multimeter, but....
> Just tested the Diode. I'm measuring 587 and 1. No beep though.
> 
> Also noticed when measuring that the wires from the diode are black, I could scrape black dust off of it. (see picture) 
> 
> http://dl.dropbox.com/u/7760238/poly%20800/Diode.JPG
> 
> --- In korgpolyex@yahoogroups.com, Gordon JC Pearce <gordon@> wrote:
> >
> > On 28/07/12 18:33, Martin Ator wrote:
> > >
> > >
> > >
> > > If there is no pop and nothing on the display, or any other noises, then
> > > probably power isn't getting into the circuits. Any of the parts
> > > designed to protect against short circuit in the power circuit could be
> > > dead. The diode I told you about is a good candidate to start looking
> > > from. I have had to replace one in the past. If you have a diode test
> > > you can check this or just see if 9v is getting to the other side of the
> > > diode.
> > > I think it is the same as a 1N4004 diode.
> > 
> > http://www.oldcrows.net/~patchell/poly800/poly800.html
> > 
> > Check the 2SB744 "pre-regulator" regulator, which is in the negative 
> > lead from the power socket.
> > 
> > D2 is just to protect against incorrect polarity.
> > 
> > -- 
> > Gordonjcp MM0YEQ
> >
>

>
> On 29/07/12 10:32, kjelle.vergauwe wrote:
> > I'm not really good with a multimeter, but....
> > Just tested the Diode. I'm measuring 587 and 1. No beep though.
> 
> A "1" in the left-most digit of the display?  That means "infinite". 
> Those readings look pretty healthy.
> 
> > Also noticed when measuring that the wires from the diode are black, I could scrape black dust off of it. (see picture)
> >
> > http://dl.dropbox.com/u/7760238/poly%20800/Diode.JPG
> >
> 
> That's just the plating getting oxidised, it's normal.
> 
> Refer to page 1 in the diagrams I linked to in my previous post, bottom 
> left corner.
> 
> With the AC adaptor plugged in and the power switch on, measure the 
> voltage across C3 (little disc ceramic capacitor) or C4 (one of the 
> three electrolytics near there).  You should see about 9V.  If not, 
> measure the voltage between the positive side of C4 and the middle leg 
> of Q1 (2SB744).  You should see whatever voltage the PSU is putting out.
> 
> You may need to remove Q1 from the board to test it, but I bet that's 
> what the fault is.  If you're not comfortable with soldering and 
> desoldering, then find some friendly neighbourhood electronics geek to 
> help you ;-)
> 
> -- 
> Gordonjcp MM0YEQ
>

>
> On 29/07/12 10:32, kjelle.vergauwe wrote:
> > I'm not really good with a multimeter, but....
> > Just tested the Diode. I'm measuring 587 and 1. No beep though.
> 
> A "1" in the left-most digit of the display?  That means "infinite". 
> Those readings look pretty healthy.
> 
> > Also noticed when measuring that the wires from the diode are black, I could scrape black dust off of it. (see picture)
> >
> > http://dl.dropbox.com/u/7760238/poly%20800/Diode.JPG
> >
> 
> That's just the plating getting oxidised, it's normal.
> 
> Refer to page 1 in the diagrams I linked to in my previous post, bottom 
> left corner.
> 
> With the AC adaptor plugged in and the power switch on, measure the 
> voltage across C3 (little disc ceramic capacitor) or C4 (one of the 
> three electrolytics near there).  You should see about 9V.  If not, 
> measure the voltage between the positive side of C4 and the middle leg 
> of Q1 (2SB744).  You should see whatever voltage the PSU is putting out.
> 
> You may need to remove Q1 from the board to test it, but I bet that's 
> what the fault is.  If you're not comfortable with soldering and 
> desoldering, then find some friendly neighbourhood electronics geek to 
> help you ;-)
> 
> -- 
> Gordonjcp MM0YEQ
>

>
> If you measure your 9v power supply do you get 12.88v?
> 
> 
> 
> ________________________________
>  From: kjelle.vergauwe <bobsrampenbedrijf@...>
> To: korgpolyex@yahoogroups.com 
> Sent: Sunday, 29 July 2012, 12:03
> Subject: [korgpolyex] Re: Poly 800 MK 1 Short circuit
>  
> 
> Â  
> I hope I did nothing wrong but here are my results...
> 
> C3 measures 0
> C4 measures 0
> 
> middle leg of Q1 with the +leg of C4  measures 12.88
> 
> I set my multimeter to 20 V DC. PSU is 9V DC PSU, which still works with other equipment.
> 
> --- In korgpolyex@yahoogroups.com, Gordon JC Pearce <gordon@> wrote:
> >
> > On 29/07/12 10:32, kjelle.vergauwe wrote:
> > > I'm not really good with a multimeter, but....
> > > Just tested the Diode. I'm measuring 587 and 1. No beep though.
> > 
> > A "1" in the left-most digit of the display?  That means "infinite". 
> > Those readings look pretty healthy.
> > 
> > > Also noticed when measuring that the wires from the diode are black, I could scrape black dust off of it. (see picture)
> > >
> > > http://dl.dropbox.com/u/7760238/poly%20800/Diode.JPG
> > >
> > 
> > That's just the plating getting oxidised, it's normal.
> > 
> > Refer to page 1 in the diagrams I linked to in my previous post, bottom 
> > left corner.
> > 
> > With the AC adaptor plugged in and the power switch on, measure the 
> > voltage across C3 (little disc ceramic capacitor) or C4 (one of the 
> > three electrolytics near there).  You should see about 9V.  If not, 
> > measure the voltage between the positive side of C4 and the middle leg 
> > of Q1 (2SB744).  You should see whatever voltage the PSU is putting out.
> > 
> > You may need to remove Q1 from the board to test it, but I bet that's 
> > what the fault is.  If you're not comfortable with soldering and 
> > desoldering, then find some friendly neighbourhood electronics geek to 
> > help you ;-)
> > 
> > -- 
> > Gordonjcp MM0YEQ
> >
>

>
> 
> Between 12.88 and 13.14.
> 
> I suspect that it should read 9 :p Hmm. 
> 
> Weird.
> 
> --- In korgpolyex@yahoogroups.com, Martin Ator <cyllall@> wrote:
> >
> > If you measure your 9v power supply do you get 12.88v?
> > 
> > 
> > 
> > ________________________________
> >  From: kjelle.vergauwe <bobsrampenbedrijf@>
> > To: korgpolyex@yahoogroups.com 
> > Sent: Sunday, 29 July 2012, 12:03
> > Subject: [korgpolyex] Re: Poly 800 MK 1 Short circuit
> >  
> > 
> > Â  
> > I hope I did nothing wrong but here are my results...
> > 
> > C3 measures 0
> > C4 measures 0
> > 
> > middle leg of Q1 with the +leg of C4  measures 12.88
> > 
> > I set my multimeter to 20 V DC. PSU is 9V DC PSU, which still works with other equipment.
> > 
> > --- In korgpolyex@yahoogroups.com, Gordon JC Pearce <gordon@> wrote:
> > >
> > > On 29/07/12 10:32, kjelle.vergauwe wrote:
> > > > I'm not really good with a multimeter, but....
> > > > Just tested the Diode. I'm measuring 587 and 1. No beep though.
> > > 
> > > A "1" in the left-most digit of the display?  That means "infinite". 
> > > Those readings look pretty healthy.
> > > 
> > > > Also noticed when measuring that the wires from the diode are black, I could scrape black dust off of it. (see picture)
> > > >
> > > > http://dl.dropbox.com/u/7760238/poly%20800/Diode.JPG
> > > >
> > > 
> > > That's just the plating getting oxidised, it's normal.
> > > 
> > > Refer to page 1 in the diagrams I linked to in my previous post, bottom 
> > > left corner.
> > > 
> > > With the AC adaptor plugged in and the power switch on, measure the 
> > > voltage across C3 (little disc ceramic capacitor) or C4 (one of the 
> > > three electrolytics near there).  You should see about 9V.  If not, 
> > > measure the voltage between the positive side of C4 and the middle leg 
> > > of Q1 (2SB744).  You should see whatever voltage the PSU is putting out.
> > > 
> > > You may need to remove Q1 from the board to test it, but I bet that's 
> > > what the fault is.  If you're not comfortable with soldering and 
> > > desoldering, then find some friendly neighbourhood electronics geek to 
> > > help you ;-)
> > > 
> > > -- 
> > > Gordonjcp MM0YEQ
> > >
> >
>

>
> If you measure your 9v power supply do you get 12.88v?
> 
> 
> 
> ________________________________
>  From: kjelle.vergauwe <bobsrampenbedrijf@...>
> To: korgpolyex@yahoogroups.com 
> Sent: Sunday, 29 July 2012, 12:03
> Subject: [korgpolyex] Re: Poly 800 MK 1 Short circuit
> 
> 
> Â  
> I hope I did nothing wrong but here are my results...
> 
> C3 measures 0
> C4 measures 0
> 
> middle leg of Q1 with the +leg of C4  measures 12.88
> 
> I set my multimeter to 20 V DC. PSU is 9V DC PSU, which still works with other equipment.
> 
> --- In korgpolyex@yahoogroups.com, Gordon JC Pearce <gordon@> wrote:
> >
> > On 29/07/12 10:32, kjelle.vergauwe wrote:
> > > I'm not really good with a multimeter, but....
> > > Just tested the Diode. I'm measuring 587 and 1. No beep though.
> > 
> > A "1" in the left-most digit of the display?  That means "infinite". 
> > Those readings look pretty healthy.
> > 
> > > Also noticed when measuring that the wires from the diode are black, I could scrape black dust off of it. (see picture)
> > >
> > > http://dl.dropbox.com/u/7760238/poly%20800/Diode.JPG
> > >
> > 
> > That's just the plating getting oxidised, it's normal.
> > 
> > Refer to page 1 in the diagrams I linked to in my previous post, bottom 
> > left corner.
> > 
> > With the AC adaptor plugged in and the power switch on, measure the 
> > voltage across C3 (little disc ceramic capacitor) or C4 (one of the 
> > three electrolytics near there).  You should see about 9V.  If not, 
> > measure the voltage between the positive side of C4 and the middle leg 
> > of Q1 (2SB744).  You should see whatever voltage the PSU is putting out.
> > 
> > You may need to remove Q1 from the board to test it, but I bet that's 
> > what the fault is.  If you're not comfortable with soldering and 
> > desoldering, then find some friendly neighbourhood electronics geek to 
> > help you ;-)
> > 
> > -- 
> > Gordonjcp MM0YEQ
> >
>

>
> You just have an unregulated power supply. When it starts working the volts will drop down to about 10 or 11. It's high because your poly isn't using any power.
> 
> If you are measuring that voltage at Q1 then power is getting there.You need to see if power is getting out now?
> 
> 
> 
> ________________________________
>  From: kjelle.vergauwe <bobsrampenbedrijf@...>
> To: korgpolyex@yahoogroups.com 
> Sent: Sunday, 29 July 2012, 12:14
> Subject: [korgpolyex] Re: Poly 800 MK 1 Short circuit
>  
> 
> Â  
> 
> Between 12.88 and 13.14.
> 
> I suspect that it should read 9 :p Hmm. 
> 
> Weird.
> 
> --- In korgpolyex@yahoogroups.com, Martin Ator <cyllall@> wrote:
> >
> > If you measure your 9v power supply do you get 12.88v?
> > 
> > 
> > 
> > ________________________________
> >  From: kjelle.vergauwe <bobsrampenbedrijf@>
> > To: korgpolyex@yahoogroups.com 
> > Sent: Sunday, 29 July 2012, 12:03
> > Subject: [korgpolyex] Re: Poly 800 MK 1 Short circuit
> > 
> > 
> >   
> > I hope I did nothing wrong but here are my results...
> > 
> > C3 measures 0
> > C4 measures 0
> > 
> > middle leg of Q1 with the +leg of C4  measures 12.88
> > 
> > I set my multimeter to 20 V DC. PSU is 9V DC PSU, which still works with other equipment.
> > 
> > --- In korgpolyex@yahoogroups.com, Gordon JC Pearce <gordon@> wrote:
> > >
> > > On 29/07/12 10:32, kjelle.vergauwe wrote:
> > > > I'm not really good with a multimeter, but....
> > > > Just tested the Diode. I'm measuring 587 and 1. No beep though.
> > > 
> > > A "1" in the left-most digit of the display?  That means "infinite". 
> > > Those readings look pretty healthy.
> > > 
> > > > Also noticed when measuring that the wires from the diode are black, I could scrape black dust off of it. (see picture)
> > > >
> > > > http://dl.dropbox.com/u/7760238/poly%20800/Diode.JPG
> > > >
> > > 
> > > That's just the plating getting oxidised, it's normal.
> > > 
> > > Refer to page 1 in the diagrams I linked to in my previous post, bottom 
> > > left corner.
> > > 
> > > With the AC adaptor plugged in and the power switch on, measure the 
> > > voltage across C3 (little disc ceramic capacitor) or C4 (one of the 
> > > three electrolytics near there).  You should see about 9V.  If not, 
> > > measure the voltage between the positive side of C4 and the middle leg 
> > > of Q1 (2SB744).  You should see whatever voltage the PSU is putting out.
> > > 
> > > You may need to remove Q1 from the board to test it, but I bet that's 
> > > what the fault is.  If you're not comfortable with soldering and 
> > > desoldering, then find some friendly neighbourhood electronics geek to 
> > > help you ;-)
> > > 
> > > -- 
> > > Gordonjcp MM0YEQ
> > >
> >
>

>
> You just have an unregulated power supply. When it starts working the volts will drop down to about 10 or 11. It's high because your poly isn't using any power.
> 
> If you are measuring that voltage at Q1 then power is getting there.You need to see if power is getting out now?
> 
> 
> 
> ________________________________
>  From: kjelle.vergauwe <bobsrampenbedrijf@...>
> To: korgpolyex@yahoogroups.com 
> Sent: Sunday, 29 July 2012, 12:14
> Subject: [korgpolyex] Re: Poly 800 MK 1 Short circuit
>  
> 
> Â  
> 
> Between 12.88 and 13.14.
> 
> I suspect that it should read 9 :p Hmm. 
> 
> Weird.
> 
> --- In korgpolyex@yahoogroups.com, Martin Ator <cyllall@> wrote:
> >
> > If you measure your 9v power supply do you get 12.88v?
> > 
> > 
> > 
> > ________________________________
> >  From: kjelle.vergauwe <bobsrampenbedrijf@>
> > To: korgpolyex@yahoogroups.com 
> > Sent: Sunday, 29 July 2012, 12:03
> > Subject: [korgpolyex] Re: Poly 800 MK 1 Short circuit
> > 
> > 
> >   
> > I hope I did nothing wrong but here are my results...
> > 
> > C3 measures 0
> > C4 measures 0
> > 
> > middle leg of Q1 with the +leg of C4  measures 12.88
> > 
> > I set my multimeter to 20 V DC. PSU is 9V DC PSU, which still works with other equipment.
> > 
> > --- In korgpolyex@yahoogroups.com, Gordon JC Pearce <gordon@> wrote:
> > >
> > > On 29/07/12 10:32, kjelle.vergauwe wrote:
> > > > I'm not really good with a multimeter, but....
> > > > Just tested the Diode. I'm measuring 587 and 1. No beep though.
> > > 
> > > A "1" in the left-most digit of the display?  That means "infinite". 
> > > Those readings look pretty healthy.
> > > 
> > > > Also noticed when measuring that the wires from the diode are black, I could scrape black dust off of it. (see picture)
> > > >
> > > > http://dl.dropbox.com/u/7760238/poly%20800/Diode.JPG
> > > >
> > > 
> > > That's just the plating getting oxidised, it's normal.
> > > 
> > > Refer to page 1 in the diagrams I linked to in my previous post, bottom 
> > > left corner.
> > > 
> > > With the AC adaptor plugged in and the power switch on, measure the 
> > > voltage across C3 (little disc ceramic capacitor) or C4 (one of the 
> > > three electrolytics near there).  You should see about 9V.  If not, 
> > > measure the voltage between the positive side of C4 and the middle leg 
> > > of Q1 (2SB744).  You should see whatever voltage the PSU is putting out.
> > > 
> > > You may need to remove Q1 from the board to test it, but I bet that's 
> > > what the fault is.  If you're not comfortable with soldering and 
> > > desoldering, then find some friendly neighbourhood electronics geek to 
> > > help you ;-)
> > > 
> > > -- 
> > > Gordonjcp MM0YEQ
> > >
> >
>

>
> On 29/07/12 12:27, kjelle.vergauwe wrote:
> > Ok I retried measuring C3 and C4. For some reason I was probably doing something wrong.
> > C3 & C4 measure  around 580 and I get a 'beep' now.
> 
> No, don't measure the resistance, measure the voltage across them.  You 
> reckon you saw 0V, so the circuit around Q1 isn't working.
> 
> This is most likely because shorting the supply killed Q1 - if you 
> notice, it's between the negative terminal of the power lead and ground. 
>   If you shorted the positive terminal of the PSU to ground, you'd dump 
> all the current the PSU can provide into Q1 backwards, and it wouldn't 
> enjoy that...
> 
> You'll probably find it'll work just fine on batteries.
> 
> -- 
> Gordonjcp MM0YEQ
>

>
> On 29/07/12 12:27, kjelle.vergauwe wrote:
> > Ok I retried measuring C3 and C4. For some reason I was probably doing something wrong.
> > C3 & C4 measure  around 580 and I get a 'beep' now.
> 
> No, don't measure the resistance, measure the voltage across them.  You 
> reckon you saw 0V, so the circuit around Q1 isn't working.
> 
> This is most likely because shorting the supply killed Q1 - if you 
> notice, it's between the negative terminal of the power lead and ground. 
>   If you shorted the positive terminal of the PSU to ground, you'd dump 
> all the current the PSU can provide into Q1 backwards, and it wouldn't 
> enjoy that...
> 
> You'll probably find it'll work just fine on batteries.
> 
> -- 
> Gordonjcp MM0YEQ
>

>
> You need a new Q1
> 
> 
> 
> ________________________________
>  From: kjelle.vergauwe <bobsrampenbedrijf@...>
> To: korgpolyex@yahoogroups.com 
> Sent: Sunday, 29 July 2012, 13:12
> Subject: [korgpolyex] Re: Poly 800 MK 1 Short circuit
>  
> 
> Â  
> Yup it still works fine on batteries. I can live with that.
> What needs to happen to make it work again on a regular PSU?
> Does the Circuitboard need to be replaced? Or wil resoldering components do the trick?
> 
> --- In korgpolyex@yahoogroups.com, Gordon JC Pearce <gordon@> wrote:
> >
> > On 29/07/12 12:27, kjelle.vergauwe wrote:
> > > Ok I retried measuring C3 and C4. For some reason I was probably doing something wrong.
> > > C3 & C4 measure  around 580 and I get a 'beep' now.
> > 
> > No, don't measure the resistance, measure the voltage across them.  You 
> > reckon you saw 0V, so the circuit around Q1 isn't working.
> > 
> > This is most likely because shorting the supply killed Q1 - if you 
> > notice, it's between the negative terminal of the power lead and ground. 
> >   If you shorted the positive terminal of the PSU to ground, you'd dump 
> > all the current the PSU can provide into Q1 backwards, and it wouldn't 
> > enjoy that...
> > 
> > You'll probably find it'll work just fine on batteries.
> > 
> > -- 
> > Gordonjcp MM0YEQ
> >
>

>
> You need a new Q1
> 
> 
> 
> ________________________________
>  From: kjelle.vergauwe <bobsrampenbedrijf@...>
> To: korgpolyex@yahoogroups.com 
> Sent: Sunday, 29 July 2012, 13:12
> Subject: [korgpolyex] Re: Poly 800 MK 1 Short circuit
>  
> 
> Â  
> Yup it still works fine on batteries. I can live with that.
> What needs to happen to make it work again on a regular PSU?
> Does the Circuitboard need to be replaced? Or wil resoldering components do the trick?
> 
> --- In korgpolyex@yahoogroups.com, Gordon JC Pearce <gordon@> wrote:
> >
> > On 29/07/12 12:27, kjelle.vergauwe wrote:
> > > Ok I retried measuring C3 and C4. For some reason I was probably doing something wrong.
> > > C3 & C4 measure  around 580 and I get a 'beep' now.
> > 
> > No, don't measure the resistance, measure the voltage across them.  You 
> > reckon you saw 0V, so the circuit around Q1 isn't working.
> > 
> > This is most likely because shorting the supply killed Q1 - if you 
> > notice, it's between the negative terminal of the power lead and ground. 
> >   If you shorted the positive terminal of the PSU to ground, you'd dump 
> > all the current the PSU can provide into Q1 backwards, and it wouldn't 
> > enjoy that...
> > 
> > You'll probably find it'll work just fine on batteries.
> > 
> > -- 
> > Gordonjcp MM0YEQ
> >
>