Vintage Synth Repair

Does anyone have any idea how a 110v MKS70 can be internally converted
to 230v ?

Thanks !

Can using a downstep transformer (230v to 110v) cause any damage to
the MKS70 transformer ?


--- In vintagesynthrepair@yahoogroups.com, PeWe <ha-pewe@...> wrote:
>
> 
> AFAIK, you have to change the transformer.
> I have a MKS70 too since many years and got it from the US,- so I
had to 

> change it too.
> 
> gil_we schrieb:
> >
> > Does anyone have any idea how a 110v MKS70 can be internally converted
> > to 230v ?
> >
> > Thanks !
> >
> > .
> >
> >
>

Provided it is of the correct rating - no.
 
Regards
Brian G3OYU
www.g3oyu.co.uk
 
  _____  

From: vintagesynthrepair@yahoogroups.com
[mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of gil_we
Sent: Friday, 16 May 2008 19:36
To: vintagesynthrepair@yahoogroups.com
Subject: [vintagesynthrepair] Re: rewiring MKS70 power supply for 230v ....
 
Can using a downstep transformer (230v to 110v) cause any damage to
the MKS70 transformer ?

--- In vintagesynthrepair@ <mailto:vintagesynthrepair%40yahoogroups.com>
yahoogroups.com, PeWe <ha-pewe@...> wrote:
>
> 
> AFAIK, you have to change the transformer.
> I have a MKS70 too since many years and got it from the US,- so I
had to 
> change it too.
> 
> gil_we schrieb:
> >
> > Does anyone have any idea how a 110v MKS70 can be internally converted
> > to 230v ?
> >
> > Thanks !
> >
> > .
> >
> >
>
 



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My Roland schematic indicates that there are various taps on the  
primary of the power transformer
for100V117V220V240V. You'll have to look inside of course.

On May 16, 2008, at 12:51 PM, gil_we wrote:

> Does anyone have any idea how a 110v MKS70 can be internally converted
> to 230v ?
>
> Thanks !
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
>

Thanks,

The transformer indeed has taps for both 240v and 220v,
but there's also an "AC Filter" board placed between the outlet
and the transformer.

See the powersupply schematics on the files section under the name of:
"mks70 ps.JPG"

The schematics shows that the only components which are different 
between the various voltage models is L1 and the fuse.

I guess that the L1 part cannot handle 220v-240v so the only way I can
still use 220v-240v is to take the filter board out entirely and 
connect the outlet directly to the transformer with a fuse placed in
between ? 

Will that work or is the filter board crucial for the correct
operation and lifespan of the instrument ?

Also, the outlet voltage here is 228v. Should I tap the 240v or 220v
input on the transformer ?

Thanks all !













-- In vintagesynthrepair@yahoogroups.com, Russell Rose <russrose@...>
wrote:

>
> My Roland schematic indicates that there are various taps on the  
> primary of the power transformer
> for100V117V220V240V. You'll have to look inside of course.
> On May 16, 2008, at 12:51 PM, gil_we wrote:
> 
> > Does anyone have any idea how a 110v MKS70 can be internally converted
> > to 230v ?
> >
> > Thanks !
> >
> >
> > ------------------------------------
> >
> > Yahoo! Groups Links
> >
> >
> >
>

Thanks,

I know the MKS70 very well. I had a failed one a while ago,
with all kind of problems. This one is untouched.

I'll use a step down transformer.


--- In vintagesynthrepair@yahoogroups.com, PeWe <ha-pewe@...> wrote:
>
> If you have an external quality downstrip transformer available, just 
> use it.
> Only disadvantage is, you have an additional external device to carry 
> around.
> 
> How old is your MKS70 ?
> Check the internal PSU for stable voltages and the caps.
> Bad voltage can damage internal circuitry, the display is the critical 
> part in the MKS70.
> It´s a VFD (and unavailable like the Oberheim Matrix12 /Xpander VFD 
> displays).
> If it fails you have a prob to get a replacement.
> 
> good luck w/ your MKS, it´s a great sounding machine ...
> 
> 
> gil_we schrieb:
> >
> > Can using a downstep transformer (230v to 110v) cause any damage to
> > the MKS70 transformer ?
> >
> > --- In vintagesynthrepair@yahoogroups.com 
> > <mailto:vintagesynthrepair%40yahoogroups.com>, PeWe <ha-pewe@> wrote:
> > >
> > >
> > > AFAIK, you have to change the transformer.
> > > I have a MKS70 too since many years and got it from the US,- so I
> > had to
> > > change it too.
> > >
> > > gil_we schrieb:
> > > >
> > > > Does anyone have any idea how a 110v MKS70 can be internally
converted

> > > > to 230v ?
> > > >
> > > > Thanks !
> > > >
> > > > .
> > > >
> > > >
> > >
> >
> >
>