Korg Poly800/EX800 Users

Many thanks, i swaped the klm-598-3 boards and all is good (at least
halfway)

I am guessing that the amp chip is either the 

inline    M5216L 3702  (IC 1)

  or

the 2x4   4558DV  JRC  4009 (IC 2)

as all the other 8 pins are clock gens or other types and they are the
only OP-Amps on the board.    

Gettin' closer, which one do I pull?


Thank you.









--- In korgpolyex@yahoogroups.com, Marcus Wilson <JB@...> wrote:
>
> the headphone output that died on my poly was on the chorus board,
> 
> there is a 8 pin SIL chip amp that is the headphone amp
> 
> I managed to replace it with an 8 pin DIL amp using some funky wiring  
> to make it work
> 
> try swapping the chorus board over to isolate the headphone amp issue  
> on one board, and if it is definately there, I can locate the part  
> number for the part i used to replace mine and bring it back to life
> 
> best regards,
> 
> Marcus Wilson
> 
> On 03/03/2008, at 4:57 AM, Funky Monkey wrote:
> 
> > Holly crap, you must be looking over my shoulder.
> >
> > I have 2 poly 800s
> >
> > Poly 1 would not run on wall DC power (only batteries) and did not  
> > output at the headphone amp and had a backup battery installed but  
> > R1 and D1 was not cut. (good keyboard action though)
> >
> > Poly 2 runs on batteries and wall DC and has headphone output (no  
> > Li-Ion installed).  But had a kina warped keybed with uneven note  
> > triggering (a later job).
> >
> > So i just now i took the good Top (Poly 1) and put it on the Good  
> > Bottom (poly 2).  Now it runs on batteries and Wall DC but still no  
> > Headphone Out.  So Im thinking that the headphone out is upperboard  
> > related.  Any help would be met with a song of praise.
> >
> >
> >
> >
> >
> >
> >
> > To: korgpolyex@yahoogroups.com
> > From: JB@...
> > Date: Mon, 3 Mar 2008 04:42:52 +0900
> > Subject: Re: [korgpolyex] Re: Question regarding backup battery mod.
> >
> > Hi there!
> >
> > when you mention the headphone amp gone bad, I had that issue with  
> > one of my polys, and I managed to jury rig a repair, that has  
> > worked well
> >
> > do you still have the first poly? and are you interested in a how  
> > to to fix the headphone amp? (im assuming that the L/R 1/4" trs  
> > connectors still output line level fine)
> >
> > best regards,
> >
> > Marcus Wilson
> > On 02/03/2008, at 3:08 AM, funkymonkeypeter wrote:
> >
> > This is my second Poly-800. The first had a problem with the
> > headphone amp and DC-in jack. This one works great and I don't want
> > to muck it up.
> >
> > If some one can answer my question I promise not to tell anyone what
> > really happened on 9/11.
> >
> > So, to cut or not to cut?
> >
> > --- In korgpolyex@yahoogroups.com, "funkymonkeypeter"
> > <funkymonkey3.14@> wrote:
> > >
> > > Regarding the instructions here:
> > >
> > > http://analog.no/mods/korg_poly-800_mk-1_battery_backup.htm
> > >
> > >
> > > * Open the Poly-800 by removing all screws at the bottom. Locate
> > > the processor board. This is the large circuit board next to the
> > > battery compartment.
> > > * In the upper left corner you'll find Resistor R1 and Diode D1.
> > > Remove these. (Just cut the legs, but leave as much as possible  
> > of the
> > > D1 legs, see next steps.)
> > > * If you have a late revision MK-1 there will be two fairly large
> > > solder "islands" in the center of the board. The battery is mounted
> > > here. The "island" to the front of the keyboard is ground.
> > > * If you have an early revision you wont find this. The battery
> > > must then be connected by wires, the plus to the junction between
> > > R1/D1 and the minus to the other leg of D1.
> > > * Any 3V lithium with solder lugs can be used as long as it is not
> > > to big physically for mounting to the board. A wristwatch type  
> > (2025,
> > > 2032) is fine.
> > >
> > >
> > >
> > > I have the model with the solder islands, do i need to cut the  
> > legs to
> > > R1 and D1? Or can I just solder to the islands and leave everything
> > > else intact?
> > >
> > > Thank you.
> > >
> >
> >
> >
> >
> >
> >
> >
> >
>