optical problem, suggestions?

[DH]

This is going to be strange one. I own a Yamaha GranTouch piano. This is
a hybrid piano - a real grand piano action with a sampled sound. There
are optical fibers for every key. You depress a key, a hammer moves up
and a small piece of metal with a hole in it breaks a beam of light
supplied by an optical fiber.

One key stopped working, _but_ if I shine a flashlight on the optical
fibers (there's a bundle of fibers located above the piano action
throughout the piano), just about _anywhere_ in the piano, the note that
wasn't working, starts working.

A work-around, until this is fixed, would be simply to mount a small light
bulb inside the piano shining on the fibers.

I've sent an e-mail to the techs at Yamaha and am waiting for a reply, and
was wondering if anyone here has any idea what is going on.

Thanks, Dave Horne

 

[Arthur Jernberg]

Seems very strange that ambient light directed at the fibre bundle will
trigger into operation a suspected defective fibre channel. Maybe with a
laser pointer or a more specefic light source you may be able to pinpointe
the exact area of the fibre bundle that is aparently activating the
defective lead. Then check the area for probable cracks or kinks in the
fibres. I suspect Yamaha will respond with necessity of replacment of the
specific fibre lead or maybe even the complete fibre bundle.
"DH" <NoSpam@home.nl> wrote in message
news:bf6knf$nlq$1@news3.tilbu1.nb.home.nl...

This is going to be strange one. I own a Yamaha GranTouch piano. This is
a hybrid piano - a real grand piano action with a sampled sound. There
are optical fibers for every key. You depress a key, a hammer moves up
and a small piece of metal with a hole in it breaks a beam of light
supplied by an optical fiber.

One key stopped working, _but_ if I shine a flashlight on the optical
fibers (there's a bundle of fibers located above the piano action
throughout the piano), just about _anywhere_ in the piano, the note that
wasn't working, starts working.

A work-around, until this is fixed, would be simply to mount a small light
bulb inside the piano shining on the fibers.

I've sent an e-mail to the techs at Yamaha and am waiting for a reply, and
was wondering if anyone here has any idea what is going on.

Thanks, Dave Horne

 

[DH]

It gets stranger yet. When I turn the piano on, the key works for about 5
or 10 minutes. I'm wondering if the actual light source diminishes over
time.

Do you know what the light source is for these fibres. The spects of
light I can see are red in color.

Just wondering ... and still waiting to hear back from Yamaha.

 

[Arthur Jernberg]

Probably an IR LED, very possible an array of them
"DH" <NoSpam@home.nl> wrote in message
news:bf948b$mt8$1@news3.tilbu1.nb.home.nl...

It gets stranger yet. When I turn the piano on, the key works for about 5
or 10 minutes. I'm wondering if the actual light source diminishes over
time.

Do you know what the light source is for these fibres. The spects of
light I can see are red in color.

Just wondering ... and still waiting to hear back from Yamaha.