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

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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