Casio CZ/ VZ/ FZ - Pro Series

Hello Leandro, if the distortion occours when more than one note is played or 
increases if more notes are added, the problem is the DAC offset... I´ve heard 
that it´s possible to adjust de DAC offset voltage by ear, you just have to 
locate the trimmer. 



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De: Leandro <leandrocassi@...>
Para: CZsynth@yahoogroups.com
Enviadas: Quarta-feira, 2 de Fevereiro de 2011 1:25:57
Assunto: [CZsynth] CZ-3000 Distorted Outputs Problem

   
Hello there! I´m restoring a pretty beat up CZ-3000 I bought for about U$S60. 
I´ve replaced all the touch switches (yes, all 60 of ´em!!!) and the volume 
fader. I´m trying to find yet the dual 50K slider pot for the chorus volume that 
also needs to be replaced. The main problem is that the output sounds very 
distorted and fuzzy even on the "cleaner" sounding patches such as Electric 
Piano or Flute, I´ve seen on other posts that some folks had the same problem 
and perhaps could be fixed by tweaking some trimmers inside the unit to reduce 
this kind of unwanted distortion. I could not find a CZ-3000 service manual, 
I´ve found the CZ-1 and CZ-5000´s, which have slightly different measurement 
values to shoot for: 


CZ-1    DAC Offset Voltage Adjustement: measure -3mV (+/-3mV) between pin 13 of 
DAC BA9221 and pin 1 of opamp TL082-1
CZ-5000 DAC Offset Voltage Adjustement: measure  0mV (+/-3mV) between pin 13 or 
19 of DAC BA9221 and pin 7 of opamp TL082-3

CZ-1    Volume Adjustement: While depressing the A3 key measure 340mV (+/-20mV) 
between ground and LINE OUT terminal with a paralleled 47k resistor (register)
CZ-5000 Volume Adjustement: While depressing a key (any) measure 360mV between 
ground and LINE OUT terminal

Which one should i refer to? Anybody has a CZ-3000 service manual or knows its 
calibrating procedures? Looking at the schematics the pins for the DAC Offset 
adjustment are the same as the CZ-5000´s but I dont know if the value should be 
the same...I´ll appreciate any help!!! Thanks!!!


 


      

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