Vintage Synth Repair

Hi, My reply was general as I had a similar problem on another piece of kit.
I will have a look at the drawing and get back to you.
Best regards.
John.
----- Original Message -----
From: "gil_we" <gil_we@...>
To: <vintagesynthrepair@yahoogroups.com>
Sent: Sunday, August 20, 2006 9:29 AM
Subject: [vintagesynthrepair] Re: What causes bad unregulated voltage on the
power supply ?


> Thanks !
>
> I uploaded the schematics to the Files section here...
>
> Are you refering to D5 ?.... But isn't it supposed to control the DC
> voltage rather then the unregulated voltage ?
>
> Thanks for any advice !!
>
>
>
> --- In vintagesynthrepair@yahoogroups.com, "John Brewer" <john@...>
> wrote:
> >
> > I have had a similar problem on another piece of equipment.  The
> bridge
> > rectifier was the culprit.  Can you scan and e-mail me the power
> supply
> > circuit and I will have a look for you.
> > JohnB
> > ----- Original Message -----
> > From: "gil_we" <gil_we@...>
> > To: <vintagesynthrepair@yahoogroups.com>
> > Sent: Sunday, August 20, 2006 12:22 AM
> > Subject: [vintagesynthrepair] What causes bad unregulated voltage
> on the
> > power supply ?
> >
> >
> > > I got a Roland MKS70 of which the Power Supply unregulated
> voltage rail
> > > is too high. The schematics says there should be +7v but I read
> 11V
> > > when the DMM is set to DC and 28v when set to AC !
> > >
> > > This fits with the fact that the display of that unit is
> overbright,
> > > showing all characters at once....
> > >
> > > But what can cause the unregulated voltage to be incorrect ?
> > > could this be bad regulators in the PS unit ??
> > >
> > > I already replaced all capacitors in the PS.
> > >
> > > Thanks all !!
> > >
> > >
> > >
> > >
> > >
> > >
> > > Yahoo! Groups Links
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > --
> > > Internal Virus Database is out-of-date.
> > > Checked by AVG Free Edition.
> > > Version: 7.1.394 / Virus Database: 268.10.7/409 - Release Date:
> 04/08/06
> > >
> > >
> >
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>
> Yahoo! Groups Links
>
>
>
>
>
>
>
>
>
>
> --
> Internal Virus Database is out-of-date.
> Checked by AVG Free Edition.
> Version: 7.1.394 / Virus Database: 268.10.7/409 - Release Date: 04/08/06
>
>