Synth-DIY Yahoo! Groups Archives

Thread

Help with 8.5v rail

2009-03-26 by mborish_2000

A few months ago, I accidentally shorted the 8.5v rail to ground while calibrating VR723. (I know, I'm an idiot.)   Common sense told me to take out TR709, check it and replace.  I replaced TR709 with a TIP31C as well as IC722 and still have the same problem on the output: 3 volts and some change.  I Removed the lead and get about 7.8 volts with the PSU unloaded and a little bit less with a 1M ohm load.  The metal oxide resistor reads about 8/10 of an ohm in circuit.

I was wondering if anybody could post what some of the voltages are in their CS-80 PSU for me.  It would be nice if I could have the voltages from TR711, TR710, D713 and IC722

RE: [yamahacs80] Help with 8.5v rail

2009-03-26 by kent spong

Hi 
 

I would replace the tip31 and instead use a BD324

 

> ,

 

To: yamahacs80@yahoogroups.com
> From: mborish_2000@...
> Date: Thu, 26 Mar 2009 16:44:01 +0000
> Subject: [yamahacs80] Help with 8.5v rail
> 
> A few months ago, I accidentally shorted the 8.5v rail to ground while calibrating VR723. (I know, I'm an idiot.) Common sense told me to take out TR709, check it and replace. I replaced TR709 with a TIP31C as well as IC722 and still have the same problem on the output: 3 volts and some change. I Removed the lead and get about 7.8 volts with the PSU unloaded and a little bit less with a 1M ohm load. The metal oxide resistor reads about 8/10 of an ohm in circuit.
> 
> I was wondering if anybody could post what some of the voltages are in their CS-80 PSU for me. It would be nice if I could have the voltages from TR711, TR710, D713 and IC722
> 
> 
> 
> ------------------------------------
> 
> Yahoo! Groups Links
> 
> 
> 


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Re: Help with 8.5v rail

2009-03-26 by mborish_2000

You mean a BD234 or 2sd234 right?  Thanks for responding Kent.  I'm going to give it a shot.  On another note, do you sell extraction springs for the ribbon controller?

-Mike

--- In yamahacs80@yahoogroups.com, kent spong <kent_spong@...> wrote:

Show quoted textHide quoted text

>
> 
> Hi 
>  
> 
> I would replace the tip31 and instead use a BD324
> 
>  
> 
> > ,
> 
>  
> 
> To: yamahacs80@yahoogroups.com
> > From: mborish_2000@...
> > Date: Thu, 26 Mar 2009 16:44:01 +0000
> > Subject: [yamahacs80] Help with 8.5v rail
> > 
> > A few months ago, I accidentally shorted the 8.5v rail to ground while calibrating VR723. (I know, I'm an idiot.) Common sense told me to take out TR709, check it and replace. I replaced TR709 with a TIP31C as well as IC722 and still have the same problem on the output: 3 volts and some change. I Removed the lead and get about 7.8 volts with the PSU unloaded and a little bit less with a 1M ohm load. The metal oxide resistor reads about 8/10 of an ohm in circuit.
> > 
> > I was wondering if anybody could post what some of the voltages are in their CS-80 PSU for me. It would be nice if I could have the voltages from TR711, TR710, D713 and IC722
> > 
> > 
> > 
> > ------------------------------------
> > 
> > Yahoo! Groups Links
> > 
> > 
> > 
> 
> 
> _________________________________________________________________
> View your Twitter and Flickr updates from one place  Learn more!
> http://clk.atdmt.com/UKM/go/137984870/direct/01/
> 
> [Non-text portions of this message have been removed]
>

Re: Help with 8.5v rail

2009-03-26 by zenithaudio2003

Hi i ad a similar problem with a minimoog , it was the zener refence zener diode , i think on the cs-80 it is the d715 , it is thermaly insulated . Look if this zener is not open or shorted . On the mini ps the diode didnt seem bad , but this was the problem ..  I hope it will help ..  here is the picture ...    http://www.flickr.com/photos/31603983@N05/3387453213/

--- In yamahacs80@yahoogroups.com, "mborish_2000" <mborish_2000@...> wrote:

Show quoted textHide quoted text

>
> You mean a BD234 or 2sd234 right?  Thanks for responding Kent.  I'm going to give it a shot.  On another note, do you sell extraction springs for the ribbon controller?
> 
> -Mike
> 
> --- In yamahacs80@yahoogroups.com, kent spong <kent_spong@> wrote:
> >
> > 
> > Hi 
> >  
> > 
> > I would replace the tip31 and instead use a BD324
> > 
> >  
> > 
> > > ,
> > 
> >  
> > 
> > To: yamahacs80@yahoogroups.com
> > > From: mborish_2000@
> > > Date: Thu, 26 Mar 2009 16:44:01 +0000
> > > Subject: [yamahacs80] Help with 8.5v rail
> > > 
> > > A few months ago, I accidentally shorted the 8.5v rail to ground while calibrating VR723. (I know, I'm an idiot.) Common sense told me to take out TR709, check it and replace. I replaced TR709 with a TIP31C as well as IC722 and still have the same problem on the output: 3 volts and some change. I Removed the lead and get about 7.8 volts with the PSU unloaded and a little bit less with a 1M ohm load. The metal oxide resistor reads about 8/10 of an ohm in circuit.
> > > 
> > > I was wondering if anybody could post what some of the voltages are in their CS-80 PSU for me. It would be nice if I could have the voltages from TR711, TR710, D713 and IC722
> > > 
> > > 
> > > 
> > > ------------------------------------
> > > 
> > > Yahoo! Groups Links
> > > 
> > > 
> > > 
> > 
> > 
> > _________________________________________________________________
> > View your Twitter and Flickr updates from one place  Learn more!
> > http://clk.atdmt.com/UKM/go/137984870/direct/01/
> > 
> > [Non-text portions of this message have been removed]
> >
>

Re: Help with 8.5v rail

2009-03-26 by mborish_2000

I don't think that that is the problem.  I'm getting 22 volts off of the rails and a voltage drop of 15 volts across the zener.  I would think that that 820 would go out if it was shorted.  Oh, I'm getting a 1.2v or 1.8v drop across the 820 ohm resistor.  (I didn't look at the board layout to see exactly which one is which)

Thanks for the response.

--- In yamahacs80@yahoogroups.com, "zenithaudio2003" <zenithaudio2003@...> wrote:

Show quoted textHide quoted text

>
> Hi i ad a similar problem with a minimoog , it was the zener refence zener diode , i think on the cs-80 it is the d715 , it is thermaly insulated . Look if this zener is not open or shorted . On the mini ps the diode didnt seem bad , but this was the problem ..  I hope it will help ..  here is the picture ...    http://www.flickr.com/photos/31603983@N05/3387453213/
> 
> --- In yamahacs80@yahoogroups.com, "mborish_2000" <mborish_2000@> wrote:
> >
> > You mean a BD234 or 2sd234 right?  Thanks for responding Kent.  I'm going to give it a shot.  On another note, do you sell extraction springs for the ribbon controller?
> > 
> > -Mike
> > 
> > --- In yamahacs80@yahoogroups.com, kent spong <kent_spong@> wrote:
> > >
> > > 
> > > Hi 
> > >  
> > > 
> > > I would replace the tip31 and instead use a BD324
> > > 
> > >  
> > > 
> > > > ,
> > > 
> > >  
> > > 
> > > To: yamahacs80@yahoogroups.com
> > > > From: mborish_2000@
> > > > Date: Thu, 26 Mar 2009 16:44:01 +0000
> > > > Subject: [yamahacs80] Help with 8.5v rail
> > > > 
> > > > A few months ago, I accidentally shorted the 8.5v rail to ground while calibrating VR723. (I know, I'm an idiot.) Common sense told me to take out TR709, check it and replace. I replaced TR709 with a TIP31C as well as IC722 and still have the same problem on the output: 3 volts and some change. I Removed the lead and get about 7.8 volts with the PSU unloaded and a little bit less with a 1M ohm load. The metal oxide resistor reads about 8/10 of an ohm in circuit.
> > > > 
> > > > I was wondering if anybody could post what some of the voltages are in their CS-80 PSU for me. It would be nice if I could have the voltages from TR711, TR710, D713 and IC722
> > > > 
> > > > 
> > > > 
> > > > ------------------------------------
> > > > 
> > > > Yahoo! Groups Links
> > > > 
> > > > 
> > > > 
> > > 
> > > 
> > > _________________________________________________________________
> > > View your Twitter and Flickr updates from one place  Learn more!
> > > http://clk.atdmt.com/UKM/go/137984870/direct/01/
> > > 
> > > [Non-text portions of this message have been removed]
> > >
> >
>