Yamaha CS80

Can't the problem be reduced by slightly bending the upper right 
(note ?) contactleaf a bit down, so the contact will close just a 
little bit earlier and will not open again while the key is bouncing ?
I guess the right switch starts the trigger, the left switch 
determines initial velocity isn't it ?
Maybe there's a weak spot on the contact-metal and cleaning it will 
reduce double-triggering too?


--- In yamahacs80@yahoogroups.com, The OldCrow <oldcrow@...> wrote:
>
>   Errant triggers are caused by contact bounce, which is due to two 
> things.  First is the design of the weighted action itself.  While 
> well-balanced, each key ultimately strikes a small rubber pad,which 
is 
> in fact the force-sensing resistor array's cover delivering that 
> immaculate aftertouch.  This results in a small bounce of the far 
end of 
> the key's 'rib' which is where the actual switch(es) are.  At times 
this 
> bounce can cause a retriggering of envelopes.  Second is the age of 
the 
> switches.  Their design is going to last a hundred years, but 
contacts 
> do wear down, and they are already 30 years old.  A little less 
contact 
> facing means a slightly wider contact gap, and a wider gap means 
the 
> above mentioned bounce has a greater chance of retriggering a note 
> envelope/rotation.
> 
>   I tinkered with a corrective circuit, but am unsure if the 
correction 
> is 'better' (essentially a one-shot with a time of 50ms or so for 
each 
> trigger switch--16 in all).
> 
> Scott
> /**/
> 
> JH. wrote:
> >> I noticed some of your keys double-trigger the notes like mine 
does.
> >> How can we fix that?
> >>     
> >
> > I've no idea.
> > It doesn't bother me much, though. As long as I don't get _wrong_ 
notes.
> > But I sometimes get them; I suspect when a bouncing key triggers 
the first voice not long enough to fully charge the capacitor of the 
S&H?
> >
> > JH. 
> >
>