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
<painintheamp@...> wrote:
>
> PS:
> 
> Thanks SO much for the service manual too
> 
> gil_we <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 
>  <painintheamp@> 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 <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
>  >  <painintheamp@> 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 <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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