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Vintage Synth Repair

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RE : [vintagesynthrepair] Re: What causes bad unregulated voltage on the power supply ?

2006-08-19 by Antoine DeschĂȘnes

bad regs, backwards bridge rectifier, bad regulator, bad rectifier, blown backwards caps, etc.

gil_we a \ufffdcrit :
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"
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"
> To:
> 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 Internal Virus Database is out-of-date.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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Antoine Desch\ufffdnes

L\ufffdche-vitrine ou l\ufffdche-\ufffdcran ? Yahoo! Magasinage.

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