[sdiy] MS-20 psu conversion from 100V to 240V

[Stewart Pye]

Hi Andy,

I've converted a few 110V synths for 240V but I can't remember if the 
MS20 was one of them.

 From the circuit it looks like you could just replace the transformer 
if you can find a suitable one, and fit it in there. If your closest 
choice is 18V or 15V secondaries I'd go with the 15V one, as the 
unregulated DC is marked as 18V on the schematic. The power dissipation 
across the regulator may be too high if you use 18V secondaries.

Something like this would be suitable:
http://www.altronics.com.au/index.asp?area=item&id=M5015


If dropout voltage is a problem you could then replace the regulators 
with low dropout types such as the LM2940-15.

Regards,
Stewart.





On 5/18/2012 12:44 AM, Andrew Simper wrote:
> I want to buy an MS-20 rev2, but the only ones I can find all have
> Japanese 100V power supplies. I have a friends 240V MS20 rev2 here and
> there is a transformer and fuse mounted on the chassie and then a
> tripple core wire from the transformer that is soldered directly onto
> the main PCB. Does anyone know if it is simply a matter of changing
> that transformer?
>
> I'm assuming that the rev2 has the same power supply as the rev1:
> http://www.korganalogue.net/korgms/images/service/ms20/circ1.gif
>
> Cheers,
>
> Andy
> --
> cytomic - sound music software
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