Vintage Synth Repair

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
>