Korg Poly800/EX800 Users

Yes, it should be lower than that if the 5V regulator section was working,
so that's a pretty good indication that no power is getting through at least
one of the power transistors. I'm digging out the schematic now.

  _____  

From: korgpolyex@yahoogroups.com [mailto:korgpolyex@yahoogroups.com] On
Behalf Of Michael Hawkins
Sent: Monday, December 27, 2010 9:36 AM
To: korgpolyex@yahoogroups.com
Subject: Re: [korgpolyex] Re: korg poly 800 power problem


  


the original email said that the voltage was still 13 volts while plugged in
to the Poly.


  _____  

From: backshall1 (dsl) <backshall1@...>
To: korgpolyex@yahoogroups.com
Sent: Sun, December 26, 2010 10:24:41 PM
Subject: RE: [korgpolyex] Re: korg poly 800 power problem

  

A newer switching supply wall wart will give you a consistent 9vdc
regardless of current flow, but an older one with a big transformer will be
12-13 volts when there isn't much power being used, and drop to 9v when you
are using the rated current. I've used ones that measure 12-13 volts without
any problems.
 
Don B.

  _____  

From: korgpolyex@yahoogroups.com [mailto:korgpolyex@yahoogroups.com] On
Behalf Of korgpolyex800
Sent: Sunday, December 26, 2010 9:58 PM
To: korgpolyex@yahoogroups.com
Subject: [korgpolyex] Re: korg poly 800 power problem


  



The wall wart should be providing a consistent 9V DC output.

If you're seeing 13 volts at the input of the Poly 800 then you need to get
a 9V DC wall wart. 13 volts will overload the on board power supply control
circuits.

Mike

--- In korgpolyex@yahoogroups.com <mailto:korgpolyex%40yahoogroups.com> ,
"n8" <natere2ster@...> wrote:
>
> hi list.
> 
> just joined and have a question perhaps someone can chime in on...
> 
> i have a korg poly 800 mkI here on the bench with a power issue.
> 
> when on batteries it runs fine, but will not run off the wall wart...
> 
> the wall wart works ok, i tested the voltage on the dc plug and it is
spitting out 13V const. I read that at the DC jack as well...
> 
> The problem so far looks like i do not get the +5V on the connector CN06A
on pin 10....is that correct?
> 
> I get the pull DC in on pin 11 so that is good!
> 
> But i need to get that 5V on pin 10 so it can be sent to the chorus board,
then to the volume / switch on?
> 
> from the rough schematics i see that Q1's base and collector are tied to
this rail, and its emitter is tied to the DJ jack....
> 
> Q3 is E-C is on the 5V line, and its base is tied to Q2 tranny which is
tied to Q15 which is tied to gnd.
> 
> Is this correct?
> 
> I assume its one of the power switching transistors are bad, how can I
confirm this? I de-soldered Q1 and have it on the breadboard.
> 
> I used the standard transistor PNP tester circuit, as seen here:
> 
> http://www.kpsec.freeuk.com/trancirc.htm
> 
> It seems to work fine, I can turn the led on when the switch is closed and
turn it off when its open...
> 
> So i guess its ok and i should put back LOL?
> 
> Anyone know of any other transistors to check?
> 
> I am looking at Q3 for some reason....
> 
> What steps down to voltage from the DC jack in out to the +5V?
> 
> I assume once i get the +5V i will be ok...
> 
> i just keep looking at Q1 and Q3 cause they are both tied into GND, the DC
jack in, and the +5V rail.....
> 
> Sorry for all the questions i am noob!
> 
> Cheers,
> 
> Nate
>