Yamaha CS80

>

--- In yamahacs80@yahoogroups.com, "faxiomas@..." <faxiomas@...> wrote:
>
> 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]
> >
>

>

--- In yamahacs80@yahoogroups.com, "faxiomas@..." <faxiomas@...> wrote:
>
> Thx again, Mike; by the way, is this tendency to drift linked to the
> Sustain/release lenght? I mean, if the Sustain is has long, mid or
> short ranges, does this change in pitch increase in speed (like an
> envelope modulating the pitch) or is that more like a sudden pitch
> drop/raise similar to a regular (lol) CS80 detuning?
> M
>
> ----Messaggio
> originale----
> Da: mborish_2000@...
> Data: 25-lug-2011 8.56 PM
> A:
> <yamahacs80@yahoogroups.com>
> Ogg: [yamahacs80] Re: KAS bug examples
>
> It's really annoying and yes it does happen a lot. Also, they can
> drift up too which is really fun. I've got a machine right now that is
> doing it. There is a long jumper on the top of the SH that goes from
> the 4016 to the non inverting input that sometimes is the problem.
> I've taken them out and put ones in with an insulation jacket and
> sometimes it solves the problem. I'm curious to see your pics if
> you've got time to post them:)
>
> -Mike
>
> --- In yamahacs80@yahoogroups.
> com, "lucidsound" <lucidsound@> wrote:
> >
> > The Sustain I bug is the
> exact problem I described on here a while ago, and hardly anyone seemed
> to have come across it before, which surprised me as I've seen it on
> just about every CS50/60/80 that I've worked on.
> >
> > This is where
> the oscillator voltages are disconnected from the KAS and held by the
> capacitors on the SH card during the Release cycle. Gradually (or
> quickly in some cases) the capacitor voltage leaks away and the pitch
> changes. The 'fix' that I came up with was to directly link the 4066
> output, the capacitor and the 3140 input on each voice with wire links
> away from the PCB. It seems that the surface of the PCB goes slightly
> conductive with age, possibly due to airborne contaminants.
> >
> > I
> have a photo of the 'fix' I used if anyone is interested.
> >
> > Lucid.
> >
> >
> > ----- Original Message -----
> > From: Mike
> > To:
> yamahacs80@yahoogroups.com
> > Sent: Monday, July 25, 2011 6:49 AM
> >
> Subject: [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]
> > >
> >
> >
> >
> >
> >
> > [Non-text portions
> of this message have been removed]
> >
>