Discussion about the Korg PolySix synthesizer

Has anybody crossed a 2SC2765 PolySix PSU transistor with a generic 2N* American Version? 

I'm low on fuses and don't want to make a mistake or give this PSU more time than it deserves.

It might be 2SC2785...

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

>
> Has anybody crossed a 2SC2765 PolySix PSU transistor with a generic 2N* American Version? 
> 
> I'm low on fuses and don't want to make a mistake or give this PSU more time than it deserves.
>

Hi Mike,

Which position in the PSU have you retrieved this transistor from?

Cheers,
Andy


On 18/07/2011 22:45, "Mike" <mborish_2000@yahoo.com> wrote:

>  
>  
>  
>    
> 
> It might be 2SC2785...
> 
> --- In PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> , "Mike"
> <mborish_2000@...> wrote:
>> >
>> > Has anybody crossed a 2SC2765 PolySix PSU transistor with a generic 2N*
>> American Version?
>> > 
>> > I'm low on fuses and don't want to make a mistake or give this PSU more
>> time than it deserves.
>> >
> 
>  
>    
> 
> 



[Non-text portions of this message have been removed]

Q5 is where I got the transistor from. I'm pretty sure that it's a 2sc2785.  If I remember correctly from studying power supplies, it is a current overload protection transistor;  when the current on R2 gets high enough to create a 0.7 v drop across the BE junction of Q5, Q5 turns on and shuts down Q2.  

I'm going to give Q2 the good old diode test now that I think about it because it might also be faulty.  Its been about six or seven months since I've been in this synth and I don't remember exactly what I did to it.

On another note, I've also got a KLM-367 clone that I never got working.  Obviously, I've got to get the 5 volt rail up first before I can find the problem in the KLM-367.

Thanks,
Mike

--- In PolySix@yahoogroups.com, Andrew Jury <andy@...> wrote:

>
> Hi Mike,
> 
> Which position in the PSU have you retrieved this transistor from?
> 
> Cheers,
> Andy
> 
> 
> On 18/07/2011 22:45, "Mike" <mborish_2000@...> wrote:
> 
> >  
> >  
> >  
> >    
> > 
> > It might be 2SC2785...
> > 
> > --- In PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> , "Mike"
> > <mborish_2000@> wrote:
> >> >
> >> > Has anybody crossed a 2SC2765 PolySix PSU transistor with a generic 2N*
> >> American Version?
> >> > 
> >> > I'm low on fuses and don't want to make a mistake or give this PSU more
> >> time than it deserves.
> >> >
> > 
> >  
> >    
> > 
> > 
> 
> 
> 
> [Non-text portions of this message have been removed]
>

--- In PolySix@yahoogroups.com, "Mike" <mborish_2000@...> wrote:
>
> Q5 is where I got the transistor from. I'm pretty sure that it's a 2sc2785.  If I remember correctly from studying power supplies, it is a current overload protection transistor;  when the current on R2 gets high enough to create a 0.7 v drop across the BE junction of Q5, Q5 turns on and shuts down Q2.  
> 
> I'm going to give Q2 the good old diode test now that I think about it because it might also be faulty.  Its been about six or seven months since I've been in this synth and I don't remember exactly what I did to it.
> 
> On another note, I've also got a KLM-367 clone that I never got working.  Obviously, I've got to get the 5 volt rail up first before I can find the problem in the KLM-367.
> 
> Thanks,
> Mike
> 

http://www.bdent.com/SearchResults.asp?Search=+2sc2785&Search.x=0&Search.y=0            ( for a 2sc2785)

Hi Mike,

Q5 should be a 2SC945 so you could try our old friend the 2N2222!

Cheers,
Andy



On 19/07/2011 10:51, "Mike" <mborish_2000@yahoo.com> wrote:

>  
>  
>  
>    
> 
> Q5 is where I got the transistor from. I'm pretty sure that it's a 2sc2785.
> If I remember correctly from studying power supplies, it is a current overload
> protection transistor;  when the current on R2 gets high enough to create a
> 0.7 v drop across the BE junction of Q5, Q5 turns on and shuts down Q2.
> 
> I'm going to give Q2 the good old diode test now that I think about it because
> it might also be faulty.  Its been about six or seven months since I've been
> in this synth and I don't remember exactly what I did to it.
> 
> On another note, I've also got a KLM-367 clone that I never got working.
> Obviously, I've got to get the 5 volt rail up first before I can find the
> problem in the KLM-367.
> 
> Thanks,
> Mike
> 
> --- In PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> , Andrew
> Jury <andy@...> wrote:
>> >
>> > Hi Mike,
>> > 
>> > Which position in the PSU have you retrieved this transistor from?
>> > 
>> > Cheers,
>> > Andy
>> > 
>> > 
>> > On 18/07/2011 22:45, "Mike" <mborish_2000@...> wrote:
>> > 
>>> > >  
>>> > >  
>>> > >  
>>> > >    
>>> > > 
>>> > > It might be 2SC2785...
>>> > > 
>>> > > --- In PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
>>> <mailto:PolySix%40yahoogroups.com> , "Mike"
>>> > > <mborish_2000@> wrote:
>>>>> > >> >
>>>>> > >> > Has anybody crossed a 2SC2765 PolySix PSU transistor with a generic
2N*
>>>> > >> American Version?
>>>>> > >> > 
>>>>> > >> > I'm low on fuses and don't want to make a mistake or give this PSU
more
>>>> > >> time than it deserves.
>>>>> > >> >
>>> > > 
>>> > >  
>>> > >    
>>> > > 
>>> > > 
>> > 
>> > 
>> > 
>> > [Non-text portions of this message have been removed]
>> >
> 
>  
>    
> 
> 



[Non-text portions of this message have been removed]