Vintage Synth Repair

Thanks you.

BTW, I managed to solve the problem simply by replacing the tantalum
with a 10uf/50v regular cap.

--- In vintagesynthrepair@yahoogroups.com, scott frye
...> wrote:
>
> PS:
>
> Thanks SO much for the service manual too
>
> gil_we wrote: Sure, here
a direct link to the manual (to big to upload):
>
> http://www.hylander.us/images/schematics/sequential/Profit5v3TechManua
> l.pdf
>
> The PS was connected to the main board when the small heatsinks were
> used. The synth is made of two boards (the programmer board and the
> voice boards) which are connected on to each other.
>
> The voiceboard only gets +15v and -15v from the main (programmer)
> board, while the main board has only one input from the power supply.
>
> The PS is only connect to that port on the main board, so no other
> connection to -15v supply in the synth.
>
> When I only connect the voice board to the -15v and +15v supplies,
> the voltages are CORRECT and no shorts... Does this indicate a
> problem on the main board ?
>
> --- In vintagesynthrepair@yahoogroups.com, scott frye
> > wrote:
> >
> > Unless the circuit was connected to a load , I dont think that
> would cause any failures.
> >
> > Does someone have a schematic that I can see?
> >
> > gil_we wrote: Thanks,
> >
> > there's no short read between ground and -15 rail on the board,
> when
> > cap is removed. The PS supplies -15v when unconnected. The rating
> of
> > the tantalum is 25v and it is placed correctly.
> >
> > One thing that I must note - when first connecting the PS, I used
> > smaller heatsinks than required for the regulator. Could the -15v
> > regulator go bad even though it still supplies -15v when the PS in
> not
> > connect to the board ?
> >
> > --- In vintagesynthrepair@yahoogroups.com, scott frye
> > > wrote:
> > >
> > > Tantalums are not at all forgiving in a reverse bias OR over-
> voltage
> > setting.
> > > Remove the cap and see if you actually have a short circuit
> first.
> > Then make sure the voltage ISNT more than the cap rating. Otherwise
> > it's POOF again.
> > >
> > > gil_we wrote: Hi all,
> > >
> > > I'm trying to solve a problem with a P5 I just got.
> > >
> > > It looks like the -15v rail on the main board is shorting.
> > > Each time I'll power it up, the 10uf tantalum capacitor which
> filters
> > > the -15v is getting fried and open (shorting) immediately.
> > >
> > > Any ideas where to start looking at ? Any common parts on the
> P5 with
> > > are known to short over time ?
> > >
> > > Thanks for the help !
> > >
> > >
> > >
> > >
> > >
> > >
> > > Scott Frye
> > > AudioFixation
> > > Consumer / Pro Audio Repair
> > > Southern VT
> > >
> > >
> > >
> > >
> > >
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> >
> >
> >
> >
> >
> > Scott Frye
> > AudioFixation
> > Consumer / Pro Audio Repair
> > Southern VT
> >
> >
> >
> >
> >
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>
>
>
>
>
> Scott Frye
> AudioFixation
> Consumer / Pro Audio Repair
> Southern VT
>
>
>
>
>
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