Vintage Synth Repair

Hi
I am looking for a circuit diagram for a TG33.
I want to see if I can use a 12 power supply to drive it.
The one that came with it is a Yamaha PC-3 10 volts 700mA.
Thanks
Royce

I can offer you a copy of the whole cct, however you should be OK with 12V
but you may want to check the operating temperatures of the regulator ccts.

 

If the Yahoo system removes the attachment contact me off list.

 

Regards

Brian G3OYU

Thanks Brian.
What a great scan. I wish I could get my ccts to scan that well.

Looks like there is a 5V reg for the digital and the full voltage is sent to power some OpAmps 
As well there is a split off regulated with a 9.1V 1A zenner but most of the load is passed through a transistor. I assume it is on a heat sink.

Did I miss anything?

So 12V should be OK.

Thanks again
Royce


--- In vintagesynthrepair@yahoogroups.com, "Brian" <brian@...> wrote:

>
> I can offer you a copy of the whole cct, however you should be OK with 12V
> but you may want to check the operating temperatures of the regulator ccts.
> 
>  
> 
> If the Yahoo system removes the attachment contact me off list.
> 
>  
> 
> Regards
> 
> Brian G3OYU
>

Hi Royce

 

No problem.  I have access to the entire Yamaha on-line database, plus I
carry a 3 CD set of schematics.  I am a professional engineer repairing, to
component level, electronic keyboards and guitar amps.  Similarly I have
access to the Kawai, Fender and Marshall databases.  Regrettably many of the
other manufacturers don't treat me as well!!

 

Your power supply schematic was lifted direct from Yamaha hence the
excellent scan.

 

Yes I would say that 12V should be OK, but as previously suggested I would
check on the temperature of the various regulator components to ensure that
things are not over-heating.

 

As an example of this my local church has a Yamaha P80.  The power unit
supplied gave a lot of trouble and I repaired it on several occasions.  Then
the inevitable happened I setup the unit for the pianist one Sunday morning
only find that the power unit had failed.  I rushed back to the workshop and
picked up a selection of spare power supplies and plugged in a Kawai unit
that gave out 20V, whereas the Yamaha unit only gave 12V.  Two years on and
all is still fine!

 

Regards

Brian G3OYU

 

From: vintagesynthrepair@yahoogroups.com
[mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of Royce
Sent: 25 February 2010 9:38 AM
To: vintagesynthrepair@yahoogroups.com
Subject: [vintagesynthrepair] Re: Yamaha TG33 power supply

 

  

Thanks Brian.
What a great scan. I wish I could get my ccts to scan that well.

Looks like there is a 5V reg for the digital and the full voltage is sent to
power some OpAmps 
As well there is a split off regulated with a 9.1V 1A zenner but most of the
load is passed through a transistor. I assume it is on a heat sink.

Did I miss anything?

So 12V should be OK.

Thanks again
Royce

--- In vintagesynthrepair@yahoogroups.com
<mailto:vintagesynthrepair%40yahoogroups.com> , "Brian" <brian@...> wrote:
>
> I can offer you a copy of the whole cct, however you should be OK with 12V
> but you may want to check the operating temperatures of the regulator
ccts.

> 
> 
> 
> If the Yahoo system removes the attachment contact me off list.
> 
> 
> 
> Regards
> 
> Brian G3OYU
>

Hi Brian,

> No problem.  I have access to the entire Yamaha on-line database, plus I
> carry a 3 CD set of schematics.  I am a professional engineer repairing, to
> component level, electronic keyboards and guitar amps.  Similarly I have
> access to the Kawai, Fender and Marshall databases.  Regrettably many of the
> other manufacturers don't treat me as well!!

That is fantastic.
You wouldn't have the sysex spec to the Yamaha MFC10 pedal board?
I'm told that it could be in the service manual.

Thanks again
Royce

Brain,
 
     You stated that you have access to the full line of scans from Yamaha. I was wondering if you could help me with my Yamaha CP-30. It was offered for free in a local free-cycle group because it blew the fuse when it was powered on. Troubleshooting would be much easier if I had a skematic. So I ask if you have one or know if maybe the fuse should be slowblo? Any help would be welcome.
 
Thanks
Wayne

--- On Thu, 2/25/10, Brian <brian@...> wrote:


From: Brian <brian@g3oyu.co.uk>
Subject: RE: [vintagesynthrepair] Re: Yamaha TG33 power supply
To: vintagesynthrepair@yahoogroups.com
Date: Thursday, February 25, 2010, 6:14 AM


  





Hi Royce
 
No problem.  I have access to the entire Yamaha on-line database, plus I carry a 3 CD set of schematics.  I am a professional engineer repairing, to component level, electronic keyboards and guitar amps.  Similarly I have access to the Kawai, Fender and Marshall databases.  Regrettably many of the other manufacturers don’t treat me as well!!
 
Your power supply schematic was lifted direct from Yamaha hence the excellent scan.
 
Yes I would say that 12V should be OK, but as previously suggested I would check on the temperature of the various regulator components to ensure that things are not over-heating.
 
As an example of this my local church has a Yamaha P80.  The power unit supplied gave a lot of trouble and I repaired it on several occasions.  Then the inevitable happened I setup the unit for the pianist one Sunday morning only find that the power unit had failed.  I rushed back to the workshop and picked up a selection of spare power supplies and plugged in a Kawai unit that gave out 20V, whereas the Yamaha unit only gave 12V.  Two years on and all is still fine!
 

Regards
Brian G3OYU
 


From: vintagesynthrepair@ yahoogroups. com [mailto:vintagesynt hrepair@yahoogro ups.com] On Behalf Of Royce
Sent: 25 February 2010 9:38 AM
To: vintagesynthrepair@ yahoogroups. com
Subject: [vintagesynthrepair ] Re: Yamaha TG33 power supply
 
  



Thanks Brian.
What a great scan. I wish I could get my ccts to scan that well.

Looks like there is a 5V reg for the digital and the full voltage is sent to power some OpAmps 
As well there is a split off regulated with a 9.1V 1A zenner but most of the load is passed through a transistor. I assume it is on a heat sink.

Did I miss anything?

So 12V should be OK.

Thanks again
Royce

--- In vintagesynthrepair@ yahoogroups. com, "Brian" <brian@...> wrote:

>
> I can offer you a copy of the whole cct, however you should be OK with 12V
> but you may want to check the operating temperatures of the regulator ccts.
> 
> 
> 
> If the Yahoo system removes the attachment contact me off list.
> 
> 
> 
> Regards
> 
> Brian G3OYU
>

Hi Wayne

 

It doesn’t list in the online list as CP-30, do you by chance have any other numbers?

 

Regards

Brian G3OYU

 

From: vintagesynthrepair@yahoogroups.com [mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of Wayne
Sent: 25 February 2010 3:51 PM
To: vintagesynthrepair@yahoogroups.com
Subject: RE: [vintagesynthrepair] Re: Yamaha TG33 power supply

 

  


Brain,

 

     You stated that you have access to the full line of scans from Yamaha. I was wondering if you could help me with my Yamaha CP-30. It was offered for free in a local free-cycle group because it blew the fuse when it was powered on. Troubleshooting would be much easier if I had a skematic. So I ask if you have one or know if maybe the fuse should be slowblo? Any help would be welcome.

 

Thanks

Wayne

--- On Thu, 2/25/10, Brian <brian@...> wrote:


From: Brian <brian@...>
Subject: RE: [vintagesynthrepair] Re: Yamaha TG33 power supply
To: vintagesynthrepair@yahoogroups.com
Date: Thursday, February 25, 2010, 6:14 AM

  

Hi Royce

 

No problem.  I have access to the entire Yamaha on-line database, plus I carry a 3 CD set of schematics.  I am a professional engineer repairing, to component level, electronic keyboards and guitar amps.  Similarly I have access to the Kawai, Fender and Marshall databases.  Regrettably many of the other manufacturers don’t treat me as well!!

 

Your power supply schematic was lifted direct from Yamaha hence the excellent scan. 

  

Yes I would say that 12V should be OK, but as previously suggested I would check on the temperature of the various regulator components to ensure that things are not over-heating. 

  

As an example of this my local church has a Yamaha P80.  The power unit supplied gave a lot of trouble and I repaired it on several occasions.  Then the inevitable happened I setup the unit for the pianist one Sunday morning only find that the power unit had failed.  I rushed back to the workshop and picked up a selection of spare power supplies and plugged in a Kawai unit that gave out 20V, whereas the Yamaha unit only gave 12V.  Two years on and all is still fine! 

  

Regards

Brian G3OYU 

  

From: vintagesynthrepair@ yahoogroups. com [mailto:vintagesynt hrepair@yahoogro ups.com] On Behalf Of Royce
Sent: 25 February 2010 9:38 AM
To: vintagesynthrepair@ yahoogroups. com
Subject: [vintagesynthrepair ] Re: Yamaha TG33 power supply

  

  

Thanks Brian.
What a great scan. I wish I could get my ccts to scan that well.

Looks like there is a 5V reg for the digital and the full voltage is sent to power some OpAmps 
As well there is a split off regulated with a 9.1V 1A zenner but most of the load is passed through a transistor. I assume it is on a heat sink.

Did I miss anything?

So 12V should be OK.

Thanks again
Royce

--- In vintagesynthrepair@ yahoogroups. com <http://us.mc558.mail.yahoo.com/mc/compose?to=vintagesynthrepair%40yahoogroups.com> , "Brian" <brian@...> wrote:

>
> I can offer you a copy of the whole cct, however you should be OK with 12V
> but you may want to check the operating temperatures of the regulator ccts.
> 
> 
> 
> If the Yahoo system removes the attachment contact me off list.
> 
> 
> 
> Regards
> 
> Brian G3OYU
>

Brian,
 
    It is an old electronic piano from the late 70's I believe. The only number onther than CP-30 I have is the serial number on it. Since it came from free-cycle there was no paperwork of any kind with it. When searching on the internet I fuond two places that said they had services manuals but wanted money for them. Since I didn't trust the web site to be truthful without a sample I won't buy from them. Other search results have given me videos of people playing and information leading me to believe that there was a CP series. Thakns for the quick response. It would be very nice if I don't have to pull the power supply out and troubleshoot it blind.
 
Thanks
Wayne

--- On Thu, 2/25/10, Brian <brian@g3oyu.co.uk> wrote:


From: Brian <brian@...>
Subject: RE: [vintagesynthrepair] Re: Yamaha TG33 power supply
To: vintagesynthrepair@yahoogroups.com
Date: Thursday, February 25, 2010, 11:16 AM


  





Hi Wayne
 
It doesn’t list in the online list as CP-30, do you by chance have any other numbers?
 

Regards
Brian G3OYU
 


From: vintagesynthrepair@ yahoogroups. com [mailto:vintagesynt hrepair@yahoogro ups.com] On Behalf Of Wayne
Sent: 25 February 2010 3:51 PM
To: vintagesynthrepair@ yahoogroups. com
Subject: RE: [vintagesynthrepair ] Re: Yamaha TG33 power supply
 
  








Brain,

 

     You stated that you have access to the full line of scans from Yamaha. I was wondering if you could help me with my Yamaha CP-30. It was offered for free in a local free-cycle group because it blew the fuse when it was powered on. Troubleshooting would be much easier if I had a skematic. So I ask if you have one or know if maybe the fuse should be slowblo? Any help would be welcome.

 

Thanks

Wayne

--- On Thu, 2/25/10, Brian <brian@g3oyu. co.uk> wrote:


From: Brian <brian@g3oyu. co.uk>
Subject: RE: [vintagesynthrepair ] Re: Yamaha TG33 power supply
To: vintagesynthrepair@ yahoogroups. com
Date: Thursday, February 25, 2010, 6:14 AM

  



Hi Royce
 
No problem.  I have access to the entire Yamaha on-line database, plus I carry a 3 CD set of schematics.  I am a professional engineer repairing, to component level, electronic keyboards and guitar amps.  Similarly I have access to the Kawai, Fender and Marshall databases.  Regrettably many of the other manufacturers don’t treat me as well!!
 
Your power supply schematic was lifted direct from Yamaha hence the excellent scan. 
  
Yes I would say that 12V should be OK, but as previously suggested I would check on the temperature of the various regulator components to ensure that things are not over-heating. 
  
As an example of this my local church has a Yamaha P80.  The power unit supplied gave a lot of trouble and I repaired it on several occasions.  Then the inevitable happened I setup the unit for the pianist one Sunday morning only find that the power unit had failed.  I rushed back to the workshop and picked up a selection of spare power supplies and plugged in a Kawai unit that gave out 20V, whereas the Yamaha unit only gave 12V.  Two years on and all is still fine! 
  

Regards
Brian G3OYU 
  


From: vintagesynthrepair@ yahoogroups. com [mailto:vintagesynt hrepair@yahoogro ups.com] On Behalf Of Royce
Sent: 25 February 2010 9:38 AM
To: vintagesynthrepair@ yahoogroups. com
Subject: [vintagesynthrepair ] Re: Yamaha TG33 power supply
  
  




Thanks Brian.
What a great scan. I wish I could get my ccts to scan that well.

Looks like there is a 5V reg for the digital and the full voltage is sent to power some OpAmps 
As well there is a split off regulated with a 9.1V 1A zenner but most of the load is passed through a transistor. I assume it is on a heat sink.

Did I miss anything?

So 12V should be OK.

Thanks again
Royce

--- In vintagesynthrepair@ yahoogroups. com, "Brian" <brian@...> wrote:

>
> I can offer you a copy of the whole cct, however you should be OK with 12V
> but you may want to check the operating temperatures of the regulator ccts.
> 
> 
> 
> If the Yahoo system removes the attachment contact me off list.
> 
> 
> 
> Regards
> 
> Brian G3OYU
>

Royce and Brian...you are obviously profesionals that know a lot better than me about all this but I always warn folk about the dangers of using unregulated power supplies into (especially) low power kit as the actual measured voltage can be much higher than specified.

Also the obvious problem (my son fried a Roland keyboard by putting in a Yamaha power supply) of the wrong polarity power supply. Its amazing that Roland and Yamaha took the opposite paths with polarity, while using identical plugs!

And...almost too ambarassed to mention this, but it does happen!...putting an AC adapter into a DC device...again the manufacturers often use the same type of plug. 

Nice to get your info Brian...I Googled your details and will add you to my "little black book" for keyboard repairs..yes? Crawley UK area?

--- In vintagesynthrepair@yahoogroups.com, "Brian" <brian@...> wrote:

>
> Hi Royce
> 
>  
> 
> No problem.  I have access to the entire Yamaha on-line database, plus I
> carry a 3 CD set of schematics.  I am a professional engineer repairing, to
> component level, electronic keyboards and guitar amps.  Similarly I have
> access to the Kawai, Fender and Marshall databases.  Regrettably many of the
> other manufacturers don't treat me as well!!
> 
>  
> 
> Your power supply schematic was lifted direct from Yamaha hence the
> excellent scan.
> 
>  
> 
> Yes I would say that 12V should be OK, but as previously suggested I would
> check on the temperature of the various regulator components to ensure that
> things are not over-heating.
> 
>  
> 
> As an example of this my local church has a Yamaha P80.  The power unit
> supplied gave a lot of trouble and I repaired it on several occasions.  Then
> the inevitable happened I setup the unit for the pianist one Sunday morning
> only find that the power unit had failed.  I rushed back to the workshop and
> picked up a selection of spare power supplies and plugged in a Kawai unit
> that gave out 20V, whereas the Yamaha unit only gave 12V.  Two years on and
> all is still fine!
> 
>  
> 
> Regards
> 
> Brian G3OYU
> 
>  
> 
> From: vintagesynthrepair@yahoogroups.com
> [mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of Royce
> Sent: 25 February 2010 9:38 AM
> To: vintagesynthrepair@yahoogroups.com
> Subject: [vintagesynthrepair] Re: Yamaha TG33 power supply
> 
>  
> 
>   
> 
> Thanks Brian.
> What a great scan. I wish I could get my ccts to scan that well.
> 
> Looks like there is a 5V reg for the digital and the full voltage is sent to
> power some OpAmps 
> As well there is a split off regulated with a 9.1V 1A zenner but most of the
> load is passed through a transistor. I assume it is on a heat sink.
> 
> Did I miss anything?
> 
> So 12V should be OK.
> 
> Thanks again
> Royce
> 
> --- In vintagesynthrepair@yahoogroups.com
> <mailto:vintagesynthrepair%40yahoogroups.com> , "Brian" <brian@> wrote:
> >
> > I can offer you a copy of the whole cct, however you should be OK with 12V
> > but you may want to check the operating temperatures of the regulator
> ccts.
> > 
> > 
> > 
> > If the Yahoo system removes the attachment contact me off list.
> > 
> > 
> > 
> > Regards
> > 
> > Brian G3OYU
> >
>

Sven,
 
     Thank you very much!!! I will have very much fun if I can get this thing working.
 
Wayne

--- On Thu, 2/25/10, Sven Braamkolk <esbra2000@...> wrote:

From: Sven Braamkolk <esbra2000@...>
Subject: RE: [vintagesynthrepair] Re: Yamaha TG33 power supply
To: vintagesynthrepair@yahoogroups.com
Date: Thursday, February 25, 2010, 1:43 PM


  



hello wayne,

I've just uploaded the files you were searching for.
have fun.

greetings sven



To: vintagesynthrepair@ yahoogroups. com
From: atlas1301962@ yahoo.com
Date: Thu, 25 Feb 2010 09:35:27 -0800
Subject: RE: [vintagesynthrepair ] Re: Yamaha TG33 power supply

  







Brian,
 
    It is an old electronic piano from the late 70's I believe. The only number onther than CP-30 I have is the serial number on it. Since it came from free-cycle there was no paperwork of any kind with it. When searching on the internet I fuond two places that said they had services manuals but wanted money for them. Since I didn't trust the web site to be truthful without a sample I won't buy from them. Other search results have given me videos of people playing and information leading me to believe that there was a CP series. Thakns for the quick response. It would be very nice if I don't have to pull the power supply out and troubleshoot it blind.
 
Thanks
Wayne

--- On Thu, 2/25/10, Brian <brian@g3oyu. co.uk> wrote:


From: Brian <brian@g3oyu. co.uk>
Subject: RE: [vintagesynthrepair ] Re: Yamaha TG33 power supply
To: vintagesynthrepair@ yahoogroups. com
Date: Thursday, February 25, 2010, 11:16 AM


  



Hi Wayne

 
It doesn’t list in the online list as CP-30, do you by chance have any other numbers?
 

Regards
Brian G3OYU 
  


From: vintagesynthrepair@ yahoogroups. com [mailto:vintagesynt hrepair@yahoogro ups.com] On Behalf Of Wayne
Sent: 25 February 2010 3:51 PM
To: vintagesynthrepair@ yahoogroups. com
Subject: RE: [vintagesynthrepair ] Re: Yamaha TG33 power supply
  
  








Brain,

 

     You stated that you have access to the full line of scans from Yamaha. I was wondering if you could help me with my Yamaha CP-30. It was offered for free in a local free-cycle group because it blew the fuse when it was powered on. Troubleshooting would be much easier if I had a skematic. So I ask if you have one or know if maybe the fuse should be slowblo? Any help would be welcome.

 

Thanks

Wayne

--- On Thu, 2/25/10, Brian <brian@g3oyu. co.uk> wrote:


From: Brian <brian@g3oyu. co.uk>
Subject: RE: [vintagesynthrepair ] Re: Yamaha TG33 power supply
To: vintagesynthrepair@ yahoogroups. com
Date: Thursday, February 25, 2010, 6:14 AM 

  



Hi Royce
 
No problem.  I have access to the entire Yamaha on-line database, plus I carry a 3 CD set of schematics.  I am a professional engineer repairing, to component level, electronic keyboards and guitar amps.  Similarly I have access to the Kawai, Fender and Marshall databases.  Regrettably many of the other manufacturers don’t treat me as well!! 
  
Your power supply schematic was lifted direct from Yamaha hence the excellent scan. 
  
Yes I would say that 12V should be OK, but as previously suggested I would check on the temperature of the various regulator components to ensure that things are not over-heating. 
  
As an example of this my local church has a Yamaha P80.  The power unit supplied gave a lot of trouble and I repaired it on several occasions.  Then the inevitable happened I setup the unit for the pianist one Sunday morning only find that the power unit had failed.  I rushed back to the workshop and picked up a selection of spare power supplies and plugged in a Kawai unit that gave out 20V, whereas the Yamaha unit only gave 12V.  Two years on and all is still fine! 
  

Regards
Brian G3OYU 
  


From: vintagesynthrepair@ yahoogroups. com [mailto:vintagesynt hrepair@yahoogro ups.com] On Behalf Of Royce
Sent: 25 February 2010 9:38 AM
To: vintagesynthrepair@ yahoogroups. com
Subject: [vintagesynthrepair ] Re: Yamaha TG33 power supply
  
  




Thanks Brian.
What a great scan. I wish I could get my ccts to scan that well.

Looks like there is a 5V reg for the digital and the full voltage is sent to power some OpAmps 
As well there is a split off regulated with a 9.1V 1A zenner but most of the load is passed through a transistor. I assume it is on a heat sink.

Did I miss anything?

So 12V should be OK.

Thanks again
Royce

--- In vintagesynthrepair@ yahoogroups. com, "Brian" <brian@...> wrote:
>
> I can offer you a copy of the whole cct, however you should be OK with 12V
> but you may want to check the operating temperatures of the regulator ccts.
> 
> 
> 
> If the Yahoo system removes the attachment contact me off list.
> 
> 
> 
> Regards
> 
> Brian G3OYU
>
 






Ontdek nu Windows phone. De smartphone van dit moment

Rob, you are correct. I meant to add that the +ve terminal is the centre connector on the plug.

Thanks
Royce

--- In vintagesynthrepair@yahoogroups.com, "robwilljy" <robwilljy@...> wrote:

>
> 
> 
> Royce and Brian...you are obviously profesionals that know a lot better than me about all this but I always warn folk about the dangers of using unregulated power supplies into (especially) low power kit as the actual measured voltage can be much higher than specified.
> 
> Also the obvious problem (my son fried a Roland keyboard by putting in a Yamaha power supply) of the wrong polarity power supply. Its amazing that Roland and Yamaha took the opposite paths with polarity, while using identical plugs!
> 
> And...almost too ambarassed to mention this, but it does happen!...putting an AC adapter into a DC device...again the manufacturers often use the same type of plug. 
> 
> Nice to get your info Brian...I Googled your details and will add you to my "little black book" for keyboard repairs..yes? Crawley UK area?
> 
> --- In vintagesynthrepair@yahoogroups.com, "Brian" <brian@> wrote:
> >
> > Hi Royce
> > 
> >  
> > 
> > No problem.  I have access to the entire Yamaha on-line database, plus I
> > carry a 3 CD set of schematics.  I am a professional engineer repairing, to
> > component level, electronic keyboards and guitar amps.  Similarly I have
> > access to the Kawai, Fender and Marshall databases.  Regrettably many of the
> > other manufacturers don't treat me as well!!
> > 
> >  
> > 
> > Your power supply schematic was lifted direct from Yamaha hence the
> > excellent scan.
> > 
> >  
> > 
> > Yes I would say that 12V should be OK, but as previously suggested I would
> > check on the temperature of the various regulator components to ensure that
> > things are not over-heating.
> > 
> >  
> > 
> > As an example of this my local church has a Yamaha P80.  The power unit
> > supplied gave a lot of trouble and I repaired it on several occasions.  Then
> > the inevitable happened I setup the unit for the pianist one Sunday morning
> > only find that the power unit had failed.  I rushed back to the workshop and
> > picked up a selection of spare power supplies and plugged in a Kawai unit
> > that gave out 20V, whereas the Yamaha unit only gave 12V.  Two years on and
> > all is still fine!
> > 
> >  
> > 
> > Regards
> > 
> > Brian G3OYU
> > 
> >  
> > 
> > From: vintagesynthrepair@yahoogroups.com
> > [mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of Royce
> > Sent: 25 February 2010 9:38 AM
> > To: vintagesynthrepair@yahoogroups.com
> > Subject: [vintagesynthrepair] Re: Yamaha TG33 power supply
> > 
> >  
> > 
> >   
> > 
> > Thanks Brian.
> > What a great scan. I wish I could get my ccts to scan that well.
> > 
> > Looks like there is a 5V reg for the digital and the full voltage is sent to
> > power some OpAmps 
> > As well there is a split off regulated with a 9.1V 1A zenner but most of the
> > load is passed through a transistor. I assume it is on a heat sink.
> > 
> > Did I miss anything?
> > 
> > So 12V should be OK.
> > 
> > Thanks again
> > Royce
> > 
> > --- In vintagesynthrepair@yahoogroups.com
> > <mailto:vintagesynthrepair%40yahoogroups.com> , "Brian" <brian@> wrote:
> > >
> > > I can offer you a copy of the whole cct, however you should be OK with 12V
> > > but you may want to check the operating temperatures of the regulator
> > ccts.
> > > 
> > > 
> > > 
> > > If the Yahoo system removes the attachment contact me off list.
> > > 
> > > 
> > > 
> > > Regards
> > > 
> > > Brian G3OYU
> > >
> >
>

Yes I am in the Crawley area.

 

Also yes unregulated power supplies do have higher than spec voltages OFF
LOAD!  Bear in mind that almost all keyboards of repute have a voltage
regulator the other side of the power in socket.  The max voltage you can
apply to the majority of these regulators is 36V.  Consequently a few volts
higher shouldn't matter.

 

Having said the foregoing I would add that it is always best to use the
manufacturer's recommended option.

 

Regards

Brian G3OYU

 

From: vintagesynthrepair@yahoogroups.com
[mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of robwilljy
Sent: 25 February 2010 9:20 PM
To: vintagesynthrepair@yahoogroups.com
Subject: [vintagesynthrepair] Re: Yamaha TG33 power supply

 

  



Royce and Brian...you are obviously profesionals that know a lot better than
me about all this but I always warn folk about the dangers of using
unregulated power supplies into (especially) low power kit as the actual
measured voltage can be much higher than specified.

Also the obvious problem (my son fried a Roland keyboard by putting in a
Yamaha power supply) of the wrong polarity power supply. Its amazing that
Roland and Yamaha took the opposite paths with polarity, while using
identical plugs!

And...almost too ambarassed to mention this, but it does happen!...putting
an AC adapter into a DC device...again the manufacturers often use the same
type of plug. 

Nice to get your info Brian...I Googled your details and will add you to my
"little black book" for keyboard repairs..yes? Crawley UK area?

--- In vintagesynthrepair@yahoogroups.com
<mailto:vintagesynthrepair%40yahoogroups.com> , "Brian" <brian@...> wrote:
>
> Hi Royce
> 
> 
> 
> No problem. I have access to the entire Yamaha on-line database, plus I
> carry a 3 CD set of schematics. I am a professional engineer repairing, to
> component level, electronic keyboards and guitar amps. Similarly I have
> access to the Kawai, Fender and Marshall databases. Regrettably many of
the
> other manufacturers don't treat me as well!!
> 
> 
> 
> Your power supply schematic was lifted direct from Yamaha hence the
> excellent scan.
> 
> 
> 
> Yes I would say that 12V should be OK, but as previously suggested I would
> check on the temperature of the various regulator components to ensure
that
> things are not over-heating.
> 
> 
> 
> As an example of this my local church has a Yamaha P80. The power unit
> supplied gave a lot of trouble and I repaired it on several occasions.
Then
> the inevitable happened I setup the unit for the pianist one Sunday
morning
> only find that the power unit had failed. I rushed back to the workshop
and
> picked up a selection of spare power supplies and plugged in a Kawai unit
> that gave out 20V, whereas the Yamaha unit only gave 12V. Two years on and
> all is still fine!
> 
> 
> 
> Regards
> 
> Brian G3OYU
> 
> 
> 
> From: vintagesynthrepair@yahoogroups.com
<mailto:vintagesynthrepair%40yahoogroups.com> 
> [mailto:vintagesynthrepair@yahoogroups.com
<mailto:vintagesynthrepair%40yahoogroups.com> ] On Behalf Of Royce
> Sent: 25 February 2010 9:38 AM
> To: vintagesynthrepair@yahoogroups.com
<mailto:vintagesynthrepair%40yahoogroups.com> 
> Subject: [vintagesynthrepair] Re: Yamaha TG33 power supply
> 
> 
> 
> 
> 
> Thanks Brian.
> What a great scan. I wish I could get my ccts to scan that well.
> 
> Looks like there is a 5V reg for the digital and the full voltage is sent
to
> power some OpAmps 
> As well there is a split off regulated with a 9.1V 1A zenner but most of
the
> load is passed through a transistor. I assume it is on a heat sink.
> 
> Did I miss anything?
> 
> So 12V should be OK.
> 
> Thanks again
> Royce
> 
> --- In vintagesynthrepair@yahoogroups.com
<mailto:vintagesynthrepair%40yahoogroups.com> 
> <mailto:vintagesynthrepair%40yahoogroups.com> , "Brian" <brian@> wrote:
> >
> > I can offer you a copy of the whole cct, however you should be OK with
12V

> > but you may want to check the operating temperatures of the regulator
> ccts.
> > 
> > 
> > 
> > If the Yahoo system removes the attachment contact me off list.
> > 
> > 
> > 
> > Regards
> > 
> > Brian G3OYU
> >
>

> Its amazing that Roland and Yamaha took the opposite paths with polarity, while using identical plugs!

Just as a sidenote, if repairing DC-operated gear adding a overvoltage / 
reverse polarity protection diode is usually not a bad idea. These are 
cheap parts that will definitely save from the more expensive external 
power supply operation related repairs. Heck, I'm constantly wondering 
why is it that gear manufacturers even consider these diodes something 
worth omitting. Definitely a wrong place to save up on mfg costs!

Anyway, with polarity protection you do lose a bit of the DC over the 
diode, but most equipment usually work even despite the drop. AC fed to 
this protected input gets clipped to whichever half cycle is allowed to 
pass, so it's a safeguard against AC as well.

Personally, I'm also quite a big fan of self-resetting thermal fuses 
these days. There's hardly ever the need to solder in a new one once you 
put one in, so it does save up time spent on glass tube fuse shopping 
sprees ;)

.Arto.
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