Casio CZ/ VZ/ FZ - Pro Series

Daniel: the distortin occurs with only one note played. i´ve been probing the circuit and found that one of the TL082-3 (the one nearest to the DAC) outputs (pin 7) is considerably louder and distorted than the other (pin 1)...I´ve replaces the opamp but it wont change...I´ve uploaded the CZ-5000 service manual download link to the files section, I hope that this makes things clearer and maybe someone can help me fix this. Cheers

--- In CZsynth@yahoogroups.com, Daniel Lamas <dylama@...> wrote:
>
> 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. 
> 
> 
> 
> ________________________________
> 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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