[pianotech] Pedal "tick"

[Ron Nossaman]

allan at sutton.net wrote:
> Happy new year everybody.
> 
> I Always Find  The Source of a Noise
> 
> But not this time!
> 
> Yamaha C-109 from 1988. I tried everything I know. Usually, the plastic 
> bushings are worn and switching them with the ones from the other pedal, 
> less used, corrects the situation. Done that, but the "tick" was still 
> there.

I had one of these way back when. Here's what I think I recall.

The tick happened at the top of the stroke. I could feel the 
pedal rod pick up the dampers, then "tick". I did all the 
things you described, with no luck. Then I cycled the pedal 
with my right hand while I touched various parts of the 
mechanism with my left. The feel that corresponded with the 
tick happened at the pivot bushing. What I found was that, 
even with new bushings, there was a small amount of slop in 
the fit. If the load was in the same direction on that pivot 
throughout the cycle, it wouldn't matter - but it wasn't. The 
spring was between the pivot and the pedal. With no damper 
spring load, the pressure at the pivot was upward. Step on the 
pedal, and the damper spring load made the load on the pivot 
reverse, the bushings shifted, and - tick. I considered adding 
an extension spring to the other side of the lever, but as I 
recall, I moved the original spring out away from the pivot. 
That put less "up" pressure on the pivot when the dampers 
weren't engaged, and killed the tick. I have no idea why this 
one insisted on ticking, when so many others built just like 
it don't, but that's the only thing I found at the time that 
worked.

So try the diagnosis by touch as well as sound to see if you 
can narrow it down. If you can find it, you can fix it.

Ron N