Yamaha CS80

Hi Mike

Thx for replying; actually I can have two references, one is 
Fernando's machine, the other is a 60: to be honest I didn't realise 
such a flaw until you mentioned it, I did really thought it was due to 
poor tuning in the first place,  so I'd like to go deeper into it; btw, 
does the pitch drift randomly go from voice to voice (e.g., play low 
then high note, does the pitch drift to high?) or does it follow 
anything near to a logic like on the glissando?
Also, could the bug 
originate from the idle/busy state in the KAS' FIFO shift register? As 
it is a fake poly assigner could the KAS  get wrong messages perhaps?
Let me know, I can't wait for further infos!
:-)

M 
----Messaggio 
originale----
Da: mborish_2000@...
Data: 25-lug-2011 7.49 AM
A: 
<yamahacs80@yahoogroups.com>
Ogg: [yamahacs80] Re: KAS bug examples

I'm planning on putting all of the troubleshooting results on my own 
website in the near future because I need full HTML to reference 
pictures, audio, and maybe some math. I need a better scope to catch 
everything related to the bugs on my CS-80 even though I already know 
temporary solutions for both of them.  I can't really justify or afford 
an amazing deep memory scope until at least sometime next month and I 
still might not do it because, well, it's gonna cost at least a few 
thousand US $.

The two bugs that I'm going to take a crack at when I 
make some posts on my website are the SH pitch drop or raise in Sustain 
I bug and the Volt/Oct Scaling bug.  The SH pitch drop or raise slowly 
changes the pitch of your release tails when you have the sustain set 
high.  The Volt/Oct Scaling bug doesn't quite scale the YM26700 
properly when pin 12 spits out the octave data...I think; this is what 
I need better test equipment for.  Like I said in the previous post, 
when you hold down one key and then play another in a different octave, 
you can hear the held down key jump a few hertz.

I'm assuming that you 
and Fernando have run into the same octave scaling problem?  If so, 
please describe your problems as well as your theory related to the 
problem.  A temporary fix is to slow down the Master Clock by replacing 
the 100pf cap in the oscillator loop with a 180pf cap. I'm not going 
say why I think it works yet because all I have is a theory without the 
proper test equipment.  This will slow your clock down to about 70K and 
also clears up about half of the double triggering.  Yes, it slows down 
the key trigger time slightly which seems like a bad idea at first, 
but, honestly, my whole machine feels more stable and most of the 
double triggering is gone.  

My machine is now tolerable but not quite 
right after the clock mod.  The held down bass key went from about a 4 
hertz drift on octave changes in a higher register to about 3/4 hertz 
drift.  
 
Sorry, but I've been busy and haven't had the time to mess 
with my CS-80 or get further with these issues. 

-Mike

--- In 
yamahacs80@yahoogroups.com, "Max Fazio" <faxiomas@...> wrote:
>
> Hi 
again
> This is for Mike: have you managed to record any example of the 
supposed KAS' bug?
> Let me know!
> M
> 
> [Non-text portions of this 
message have been removed]
>