[sdiy] Prophet 600 Syndrome ?

[Csaba Zvekan]

Thank you for all your help.

This morning I have resolved my issue with my Prophet 600. The problem  
was a resistor in the voltage divider section that goes straight into  
the summer section of the CEM3340. I replaced the resistor with the  
same value and voilà it was working again.

Thank you again

Csaba


On Jun 4, 2008, at 11:29 AM, Csaba Zvekan wrote:

> LOL. thanks Pete :)
>
> So just go any preset turn the MIXER all the way to the right  
> (Clockwise) we want to exclusively listen to OSC B's . And then try  
> to play the last two octaves with frequency  set to 8 or even 10.  
> Frequency on Oscillator B.
> If it works I know I have a problem. Maybe the corresponding CEM3372  
> is causing all that .I read something like that.
>
> I greatly appreciate it
>
> Csaba
>
> On Jun 4, 2008, at 7:21 AM, Pete wrote:
>
>> Honestly im pretty sure mine doesn't do what yours is doing, but im
>> willing to help you out since I have a p600. How do you test each
>> voice so I can try it?
>>
>> pete
>>
>> On Tue, Jun 3, 2008 at 1:35 PM, Csaba Zvekan <czvekan at gmail.com>  
>> wrote:
>>> Hi Synthpeople,
>>>
>>> After replacing various IC's, capacitors, CEM's I wonder if this  
>>> what I am
>>> encountering is maybe "normal" for the Prophet 600.
>>>
>>> When I tune the frequency higher than 6 on the OSCI B the Voice 3  
>>> B is not
>>> playing in tune in the higher octaves.
>>>
>>>
>>> So then I have replaced the following :
>>>
>>> 1. All tantalum capacitors to electrolyte capacitors with  the  
>>> equivalent
>>> value.
>>>
>>> 2. I replaced U416 the CMOS 4051 (even added a 0.1uF bypass  
>>> capacitor)
>>>
>>> 3. Replaced all the 10nF capacitors
>>> (C423,C422,C421,C424,C417,C418,C419,C420)
>>>
>>> 4. Replaced the CEM3340 (VOICE  3B)
>>>
>>> 5. Replaced the CEM3372(VOICE 3)
>>>
>>> 6. All the 0.1uF caps around the VOICE 3
>>>
>>> 7. And of course OP-AMP U423 with TL-082
>>>
>>>
>>>
>>> Still no Luck. I mean the synth performs and tunes very well  
>>> except when you
>>> tune OSC B in a very high pitch.
>>> I slowly wonder if that is limitation of something in the DAC or  
>>> somewhere
>>> else. Since this is not making sense. All other voices play and  
>>> scale fine
>>> in high pitch but that Voice 3B.
>>> Before I troubleshoot any further can somebody who has a PROPHET  
>>> 600 confirm
>>> that this a known bug or otherwise let me know that the OSC B  
>>> scales and
>>> plays fine in the higher octaves as well ?
>>>
>>>
>>> Thanks
>>>
>>> Csaba
>>> _______________________________________________
>>> Synth-diy mailing list
>>> Synth-diy at dropmix.xs4all.nl
>>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>>>
>>
>>
>>
>> -- 
>> http://www.myspace.com/23isgood
>
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music stuff
http://www.csaba.ch
electronic stuff
http://www.synthmaniac.com
synthesizer stuff (not fully set up yet)