Casio CZ/ VZ/ FZ - Pro Series

James, You should be able to play 8 notes in normal mode with a 2 line patch. Tone mix mode will only play 4 notes if they are layered and 2 line patches. Maybe a reset will help otherwise you have a hardware issue with one of the two voice chips not playing its compliment of 8 voices. Look for bad solder connections but the only way I've found to isolate this is to desolder and lift VD0 (pin 30) the power leg to one of the voice chips to prove which chip isn't passing its output. The good chip will go silent. I've done this in a CZ5000 to isolate a distorted voice chip. I then replaced it with a UPD933 from a CZ101. However the CZ1 has the newer UPD933AC 8 voice chip which will only be found in a CZ1. This is not a simple thing to fix and even more fun to troubleshoot. The full CZ1 service Manual is posted in one of the CZ groups.       
Good luck, Fran
--- In CZsynth@yahoogroups.com, "wjamesmeagher" <w.james.meagher@...> wrote:
>
> I've been playing around with the CZ1 I bought recently and have noticed that in Normal mode it's dropping the lowest note played once I engage a fifth note (i.e. it can play 4 notes at once at most and will drop the lowest note to play the note of the fifth key pressed). 
> 
> My understanding though is that in normal mode (with 2 oscillators engaged) I should be able to play 8 notes together, not 4. If I drop the tone to one oscillator I can play 8 notes simultaneously, but not a 9th without it dropping the lowest held note - but with only one oscillator engaged I think I should be able to hold 16 notes. So, in a nutshell, seems to me the polyphony is cut in half to a total of 8 voices and not 16 as I expect it should be. 
> 
> Perhaps I am simply wrong about this, or am missing something - but I've only owned this synth for a few weeks, and have only been investigating vintage synths for a few months, so this is all pretty new to me. One person on the Vintage Synthesizer Forum believed someone else in this group had a similar issue some time ago. 
> 
> Any advice/insights welcome!
> 
> Cheers,
> James
>