Vintage Synth Repair

Hi folks,

I'm replacing the 110v PSU in one of these - have located an equivalent (not
Yamaha)  230v SMPS with +5V and +/-15V.

I have the commonly-available Service Manual off the net, but this does not
include schematics or a description pin-out of the PSU connector.  Also the
overlay seems to show one fewer pin on the DC-output connector than the than
the Real Thing actually has.

Now, it was easy-peasy to figure out the 5V (pin1+2)  and +15 (pin8) and
-15V (pin 7), and two commoned earth pins (3+4), but there are two more pins
pins (5 and 6) with separate tracks leading away. I can no longer check what
is on them voltage-wise or whatt their purpose is.

Any ideas, or anybody have the schematics ?

cheers

geoff

I have. If you need I can took relevant pages from that big PDF and  
send. Or send whole SM somewhere, it has over 6 MB.

CN1:
Pin 1+2 = + 5 V
Pin 3+4 = Ground
Pin 5 = AG (is it analog ground?)
Pin 6 = - 15 V
Pin 7 = + 15 V
Pin 8 = VM (??? - it goes from +line directly after diode and  
capacitor, before +15 V regulator, and continues to another  
transistor stabilizer on another PCB, and then to the base of  
transistors which are directly at all output jacks and open way to  
signal).

Daniel Forro

On Mar 31, 2011, at 4:50 PM, Geoff Wood wrote:

> Hi folks,
>
> I'm replacing the 110v PSU in one of these - have located an  
> equivalent (not
> Yamaha)  230v SMPS with +5V and +/-15V.
>
> I have the commonly-available Service Manual off the net, but this  
> does not
> include schematics or a description pin-out of the PSU connector.   
> Also the
> overlay seems to show one fewer pin on the DC-output connector than  
> the than
> the Real Thing actually has.
>
> Now, it was easy-peasy to figure out the 5V (pin1+2)  and +15  
> (pin8) and
> -15V (pin 7), and two commoned earth pins (3+4), but there are two  
> more pins
> pins (5 and 6) with separate tracks leading away. I can no longer  
> check what
> is on them voltage-wise or whatt their purpose is.
>
> Any ideas, or anybody have the schematics ?
>
> cheers
>
> geoff

I have now small problem with power supply inside my Kawai K5000W.

I moved to Japan from Europe and there are two different voltages in  
my studio (220 V and 100 V) which can be dangerous. By my mistake  
Kawai got 220 V, not 100, because I changed internal connection on  
PSU when repaired FDD, and after returning the instrument back to its  
place in my studio I didn't realized it and used 220 V (cabel end was  
the same).

Fortunately transformer survived, 17 V symmetric section works. 5 V  
section gives only 0.5 V on output. Zener diode D8 is OK after  
measuring outside the PCB, so I hope that all following PCB's with  
digital circuitry survived... This diode is unfortunately the only  
protection.

So it looks I need to change these components:

F2 - ICP-N25 (IC Protector)
U2 - Mitsubishi M5291P (DC/DC Switching Supply Converter/Regulator)
Q1 - Sanyo 2SA1641 S/T (transistor)
maybe  Q3 - Sanyo 2SD1246 S/T (transistor)

I tried different shops on net, Japanese, American (of course  
Digikey, Mouser...), but they haven't these components. Neither I  
could find some substitutions (maybe U2 can be substituted by  
MC34063AP1, I have to compare datasheets. Does somebody know  
equivalent types?

Could somebody please recommend me some good shop anywhere? I'lll be  
grateful for any help as K5000 is one of my favorite instruments...  
Of course even after PS repair there's a chance digital circuitry  
didn't survived despite that double protection and Zener... In that  
case I must buy whole instrument, or at least K5000R rack version...

Service department of Kawai Japan headquarters in Hamamatsu refused  
repair, I have called there. They don't do any repair or sell parts  
for instruments older than 10 years, maybe it's some new law in Japan  
because Yamaha has same policy now.

Thanks for any hint.

Daniel Forro

HI,
I  replaced some times ago my display on my K5000W because of the high-pitch tone coming from the DC/DC converter.
If you replace the display with a led backlight (like this one: http://www.zinguy.com/lcdpage.htm), you don't need the DC/DC converter anymore ; the 5V DC output from the power supply will suffice.
I remember that my DC/DC converter was a SUMIDA one, but I don't remember the reference.

Maybe you'll find detailed information on the K5000 group:
http://launch.groups.yahoo.com/group/K5000/

/Greg

--- In vintagesynthrepair@yahoogroups.com, Daniel Forró <dan.for@...> wrote:

>
> 
> I have now small problem with power supply inside my Kawai K5000W.
> 
> I moved to Japan from Europe and there are two different voltages in  
> my studio (220 V and 100 V) which can be dangerous. By my mistake  
> Kawai got 220 V, not 100, because I changed internal connection on  
> PSU when repaired FDD, and after returning the instrument back to its  
> place in my studio I didn't realized it and used 220 V (cabel end was  
> the same).
> 
> Fortunately transformer survived, 17 V symmetric section works. 5 V  
> section gives only 0.5 V on output. Zener diode D8 is OK after  
> measuring outside the PCB, so I hope that all following PCB's with  
> digital circuitry survived... This diode is unfortunately the only  
> protection.
> 
> So it looks I need to change these components:
> 
> F2 - ICP-N25 (IC Protector)
> U2 - Mitsubishi M5291P (DC/DC Switching Supply Converter/Regulator)
> Q1 - Sanyo 2SA1641 S/T (transistor)
> maybe  Q3 - Sanyo 2SD1246 S/T (transistor)
> 
> I tried different shops on net, Japanese, American (of course  
> Digikey, Mouser...), but they haven't these components. Neither I  
> could find some substitutions (maybe U2 can be substituted by  
> MC34063AP1, I have to compare datasheets. Does somebody know  
> equivalent types?
> 
> Could somebody please recommend me some good shop anywhere? I'lll be  
> grateful for any help as K5000 is one of my favorite instruments...  
> Of course even after PS repair there's a chance digital circuitry  
> didn't survived despite that double protection and Zener... In that  
> case I must buy whole instrument, or at least K5000R rack version...
> 
> Service department of Kawai Japan headquarters in Hamamatsu refused  
> repair, I have called there. They don't do any repair or sell parts  
> for instruments older than 10 years, maybe it's some new law in Japan  
> because Yamaha has same policy now.
> 
> Thanks for any hint.
> 
> Daniel Forro
>

Hi,

thanks for advice, but I was not talking about inverter transformer  
Sumida S147948 making high voltage for backlight foil. That one is  
probably OK, I can check it after repair of +5 V section in PSU.

That M5291P IC is responsible for regulating +5 V.

Daniel Forro

On Apr 1, 2011, at 6:17 AM, baumont987 wrote:

>
> HI,
> I  replaced some times ago my display on my K5000W because of the  
> high-pitch tone coming from the DC/DC converter.
> If you replace the display with a led backlight (like this one:  
> http://www.zinguy.com/lcdpage.htm), you don't need the DC/DC  
> converter anymore ; the 5V DC output from the power supply will  
> suffice.
> I remember that my DC/DC converter was a SUMIDA one, but I don't  
> remember the reference.
>
> Maybe you'll find detailed information on the K5000 group:
> http://launch.groups.yahoo.com/group/K5000/
>
> /Greg
>