Casio CZ/ VZ/ FZ - Pro Series

Leandro,

I had a CZ5000 that was doing this same distortion thing and it wound up being one of the uPD933 voice chips was bad. I bought a used and abused CZ101 main board on Ebay and used that for a donor. Now it plays fine.

Since there are two voice chips see if the distortion is on all 8 notes or just 4 of them. Take a single line patch. Play one note then two without releasing the first note. Keep doing this until you have all 8 notes held down. Are all 8 notes distorted? Lift the power leg of one voice chip and then the other and see if it changes. Hopefully you'll get the proper chip one the first try if one of them is bad. My luck was the wrong one first try. Oh well....

Fran 

--- In CZsynth@yahoogroups.com, "Leandro" <leandrocassi@...> wrote:
>
> 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!!!
> > 
> > 
> >  
> > 
> > 
> >       
> > 
> > [Non-text portions of this message have been removed]
> >
>