Good Job Tom, Now the 64K question, Who started the screw up, A dealer? The furniture person? or Finally an Ill imformed piano tech? Roger At 12:03 AM 19/12/99 -0800, you wrote: >To update the list about the Yamaha MX100 problem (studio upright with >Disklavier): > >I returned to the customer today armed with a long list of things to >look for. Having all your suggestions was very helpful although no one >had the problem nailed. It might have helped the diagnosis if I had >taken DW/UW measurements on the _black_ keys, hindsight being better >than foresight. > >The first thing I checked was the case for evidence of a fall and, right >away, I found just that. Someone had left some obvious scratch marks >from sandpaper plus there was orange peel black lacquer over that on the >front surfaces of the cheeks and toes (the case is polished ebony). >After all my careful checking of down-weights and up-weights last time, >I missed this amateurish repair job staring right at me. > >Next, I looked very carefully to see if the fall had changed the >relationships between the keys, action and strings. The right cheek was >damaged more extensively - a wider area was repaired - and I had thought >that this might have something to do with the treble keys being harder >to depress. > >But everything looked normal. The dowel capstans were in the middle of >the wip heels from bass to treble. There was no evidence that the keybed >or action support bolts had moved. I removed the action and saw that the >rail was not bent and the little rubber-booted screw, mounted on the >back of the main action rail, was contacting the plate strut (so no >flexing). > >After I laid the action aside, I exercised the keys up and down and >found them to be quite free... until I got past the middle of the piano >and noticed that there was some kind of resistance to key motion in the >treble, almost like very tight balance pin holes. But then I noticed the >metal key stop rail which, in the Disklavier, runs directly over the >balance rail between the two rows of pins. As I lifted the bass keys to >check for balance pin hole tightness, I could lift the keys slightly >before they contacted the felt underneath the key stop rail. But in the >treble, there was no clearance at all. Someone had unthinkingly >tightened two of the fixing screws, which bear against coil springs >underneath the rail, too far which caused the keys to bind slightly. (It >was not the usual nut on the bottom, nut on the top design.) > >As soon as I backed off the screws a couple of turns, there was >clearance above _all_ of the key buttons, the touch returned to normal >and the customer was happy. > >1 hour of sleuthing and 1 minute of adjustment did the trick. > >Tom > >-- >Thomas A. Cole, RPT >Santa Cruz, CA >mailto:tcole@cruzio.com > Roger Jolly Saskatoon, Canada. 306-665-0213 Fax 652-0505
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