Korg DW8000, Mono/Poly, MS-20...

---Russ, Thanks for the insight. I did the proceedure outline in your 
last email and it was straight forward. I now feel confident with the 
whole replacement. 



In DW8000@yahoogroups.com, Russell Rose <russrose@m...> wrote:
>
> okay. On the same service bulletin that Korg issued on Oct1990(for  
> you history buffs)
> they also outlined battery sub procedure for the Poly-6, which is  
> simply replacing the battery
> and removing R91(100 ohm) and putting diode in its place. So the  
> point being why would their engineers put a tech to
> the extra work, unless there was a good reason. My guess is this: 
to  
> reduce the drain current
> on the backup battery. I dont have a schematic in front of me but 
I  
> guess that a precious
> amount of your battery's current is being wasted on forward 
biasing  
> Q10, thereby reducing
> battery life. If you have the means check the refresh voltage at 
the  
> RAM, with power off,
> should be around 2.8-3.1 volts Or check the current drain on the  
> battery(power off)
> should be less than a coupla microamps, ideally less than one  
> microamp. I have no
> thoughts on your other Ni-Hydride battery question without 
checking  
> the specs/characteristics
> of the two batteries in question. Russ
> On Oct 27, 2005, at 11:59 PM, lnz2166 wrote:
> 
> > --- In DW8000@yahoogroups.com, Russell Rose <russrose@m...> wrote:
> >
> >> Holy Smokes, I took a chance before I got this message and just
> >>
> > removed R70 and replaced it with a Diode. It worked, I'm able to
> > store programs and it holds them in memory. Thats not to 
say,looking
> > at your email that doing it my way wont have any long term 
affects.
> > Varta makes Nickel Metal Hydride batteried which are recharable.
> > Wondering if this wouldn't be an easier solution?
> > Any thoughts
> >
> >
> >>
> >>
> >
> >
> > A wee bit more to it than that.
> >
> >> According to Korg service bulletin for poly-61.
> >> 1) remove R70(470 ohm)
> >> 2)Remove transistor Q10
> >> 3)Rep-lace nicad with lithium battery in same location
> >> 4)solder one 1N914 diode(or equiv) at location R70 and and 
another
> >> between Emitter and collector of Q10( cathode to C and anode to 
E)
> >> 5) if the CPU board is KLM475, change R146 to 2.2k ohm.
> >> if Cpu board KLM506 disregard R146
> >> pretty sure this procedure is accurate from more than one
> >>
> > experience.
> >
> >> the diode at position R70 by the way, mounts on the PCB with its
> >>
> > anode
> >
> >> pointecd towards Q10, cathode pointed towards(not connected) the
> >> positive end of battery.good luck. Russ
> >>
> >> On Oct 26, 2005, at 9:51 PM, lnz2166 wrote:
> >>
> >>
> >>> Any one have the proceedure for replacing the NiCad to Coin 
cell?
> >>>
> > I
> >
> >>> think you need to add a diode and possibly remove a capacitor.
> >>>
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