Touch Weight Too Heavy on MX100

[Roger Jolly]

Hi Tom,
            From the touch weight spreads it looks as of the treble action
mount bolt is too far out from the strings. Two checks. Is the dip shallow
towards the treble? Check that the capstans are lifting the wips at the
same distance bass to treble.
You could also have a twisted action rail.
Another thing to check, the rail has a spacing bolt that presses against
the plate.  Press on the rail with a screw driver to make sure the rail is
not flexing.  This can give you a clue to a possible twisted rail
Just some thing to check, before starting a weight off. As would doubt if
this instrument left the factory with these kind of weights.
Regards Roger 


At 09:02 PM 08/12/99 -0800, you wrote:
>Dear List,
>
>I tuned a Yamaha MX100A (1988) today that had a touchweight problem I
>found curious. It was the first thing the customer remarked about so I
>did some investigation. 
>
>I noticed right away that the dampers picked up early but, with the
>dampers picked up by the pedal, the up and down weights were too high as
>well.
>
>  NOTE	DW	UW
>
>	C2	53	34
>	C3	57	36
>	C4	60	36
>	C5	64	38
>	C6	62	38
>	C7	62	39
>	B7	75	41	(C8 felt like it had a mechanical problem)
>
>There doesn't seem to be a friction problem and so the simple solution
>would seem to be to put lead weights in the keys to bring the
>touchweight down but I've never seen a Yamaha that was so out of
>regulation. Is there something about early Disklaviers that I need to
>know? Could this particular instrument have come from the factory that
>way?
>
>Unfortunately, I didn't think to pull out some key sticks to see if
>someone had pulled out the key leads. I did glance down the side of some
>Bs and Es in the bass to check for key leads and didn't see any nor any
>empty holes. 
>
>The present owner bought it 3 years ago and the touch was heavy when she
>first got it. So far, two technicians have not been able to help her
>out, one of whom was a Yamaha tech.
>
>Thought I'd run it by the list before getting the lead out. Can anyone
>comment on this weighty subject?
>
>Tom
>-- 
>Thomas A. Cole, RPT
>Santa Cruz, CA
>mailto:tcole@cruzio.com
> 
Roger Jolly
Saskatoon, Canada.
306-665-0213
Fax 652-0505