[sdiy] korg poly 800 power problem

[Doug Terrebonne]

Is the adapter the right polarity? The Poly 800 needs 9V center-negative...



----- Original Message ----
> From: Nathan M. Reeves <djservs at comcast.net>
> To: synth diy <synth-diy at dropmix.xs4all.nl>
> Sent: Tue, December 21, 2010 7:00:38 PM
> Subject: [sdiy] korg poly 800 power problem
> 
> hello & happy holidays synth nuts!
> 
> i am having a heck of a time following the schematics for my poly 800....
> 
> the problem i am experiencing with this unit is that it will turn on and run 
>fine on the batteries ( 8x C cell 1.5V) but when the batters are out and I plug 
>in my korg adapter wall wart, it will not power on.
> 
> I am looking at the schematics and cannot tell where to test the voltages that 
>are input from the dc jack.
> 
> DC jack => GND and hot goes to 5-11B?  looks like there is a diode D2 between 
>the GND and hot connection....
> 
> the power switch is VR4, and i cannot find it anywhere on the schemo
> 
> so if the battery powers the unit but the dc jack input does not, what and 
>where can i probe to find the faulty component / short?
> 
> sorry i have looked over the schemo for an hour now and my head hurts (so 
>scrunched and tiny!)
> 
> i was hoping it was a blown fuse or the like...i am used to keyboards with IEC 
>plugs that go to fuses, diode bridge, filter caps, etc that you can then test to 
>see if the power rails are all in spec.
> 
> this is new to me....
> 
> any advice will be appreciated!  
> 
> if anything i will just run off the battery!
> 
> cheers!
> 
> nate
> 
> 
> 
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