SH-2000 TROUBLE!

[Zarone Fernando]

Dear friends, I have bought two SH-2000s. One used to work when I  
switched it on (except Fuzz-guitar presets), the other didn't (just a  
noise). I swapped the VCO / VCF vertical boards to understand where  
the problem was, and it  worked completely. After replacing them back,  
I did something wrong and now:  NO ONE WORKS ANYMORE. After  
appreciating my technical skill (if as a dentist I were that  
clever... :-), I noticed that now both synths have the same problem:  
The only tab that works is the BANJO one... and the three first ones  
(Hold, long sustain etc.). The filter sliders don't change anything in  
the sound also in the Filter Manual position.
Could you please help me in detecting the problem (and indicating the  
solution)?
The service manual is here    http://rvgm.l4rge.com/

Thank you very much
Fernando

[Zarone Fernando]

BTW, in the meanwhile I have checked the double transistor ITS 1276,  
using my DVM it doesn't behave like ... two transistors!
If it is the problem, can I check if this is true by using two  
standard transistors (while waiting for a replacement)? Moreover, any  
idea about where to find them?

Help!



Il giorno 06/nov/2009, alle ore 19.06, Zarone Fernando ha scritto:

> Dear friends, I have bought two SH-2000s. One used to work when I  
> switched it on (except Fuzz-guitar presets), the other didn't (just  
> a noise). I swapped the VCO / VCF vertical boards to understand  
> where the problem was, and it  worked completely. After replacing  
> them back, I did something wrong and now:  NO ONE WORKS ANYMORE.  
> After appreciating my technical skill (if as a dentist I were that  
> clever... :-), I noticed that now both synths have the same problem:  
> The only tab that works is the BANJO one... and the three first ones  
> (Hold, long sustain etc.). The filter sliders don't change anything  
> in the sound also in the Filter Manual position.
> Could you please help me in detecting the problem (and indicating  
> the solution)?
> The service manual is here    http://rvgm.l4rge.com/
>
> Thank you very much
> Fernando

[Zarone Fernando]

The end of the trouble.
I replaced the ITS 1276 in both the machines with LM394CH.

They are like new now.

THANKS

Fernando


Il giorno 06/nov/2009, alle ore 19.46, Zarone Fernando ha scritto:

> BTW, in the meanwhile I have checked the double transistor ITS 1276,  
> using my DVM it doesn't behave like ... two transistors!
> If it is the problem, can I check if this is true by using two  
> standard transistors (while waiting for a replacement)? Moreover,  
> any idea about where to find them?
>
> Help!
>
>
>
> Il giorno 06/nov/2009, alle ore 19.06, Zarone Fernando ha scritto:
>
>> Dear friends, I have bought two SH-2000s. One used to work when I  
>> switched it on (except Fuzz-guitar presets), the other didn't (just  
>> a noise). I swapped the VCO / VCF vertical boards to understand  
>> where the problem was, and it  worked completely. After replacing  
>> them back, I did something wrong and now:  NO ONE WORKS ANYMORE.  
>> After appreciating my technical skill (if as a dentist I were that  
>> clever... :-), I noticed that now both synths have the same  
>> problem: The only tab that works is the BANJO one... and the three  
>> first ones (Hold, long sustain etc.). The filter sliders don't  
>> change anything in the sound also in the Filter Manual position.
>> Could you please help me in detecting the problem (and indicating  
>> the solution)?
>> The service manual is here    http://rvgm.l4rge.com/
>>
>> Thank you very much
>> Fernando
>