HI John First, make sure the pedal solenoid is properly adjusted. On a grand the first adjustment to make is the amount of damper lift. This is done by adjusting the large nut on the end of the rod sticking out of the solenoid. Pull down on the rod to manually lift the dampers. The bicord wedges should just be below the top of the strings- you don't want them coming above the strings. It is important (critical) to minimize the amount of damper travel. Make sure that the lever does not hit the stop screwed into the keybed above the pedal lift rod. You definitely do not want the solenoid jamming the lever against that stop. That will create its own noise. Once the damper lift is set, tighten the jam nut. Then you must adjust the lost motion. This is done by turning down the stop at the top of the soleniod. There is a jam nut on the top. Loosen it then you can turn the threaded rod to raise or lower the stop. Lower the stop until the dampers just start to ring, then back off a little. You want very little to none lost motion. Then tighten the jam nut on top. Doing these adjustments will set the trapwork to the absolute minimum travel and may eliminate any noise. If the noise persists you must determine if there is anything hitting at any point along the trapwork. Often the passage for the lift rod through the keybed is narrow and sometimes there is interference there. Another thing to check. I've seen this on Young Changs. There is an extension off the backside of the keybed that the trapwork pivot brackets are screwed to. I have diagnosed wood on wood knocking noises coming from that extension. As the solenoid engages it loads up the trapwork creating a bending load on that extension. After seeing that happen I made a design change to all future Young Chang installations. I simply use a 90 degree mending plate bracket (available in all hardware sections) to rigidly anchor the backside of that extension to one of the beams, preferably as close to the trapwork pivot as possible. Then make sure that the large screws holding the extension to the keybed are really, really tight. You might even need to take the extension off and use some urethane glue to secure it in place. Hope this helps. Dean Dean May cell 812.239.3359 PianoRebuilders.com 812.235.5272 Terre Haute IN 47802 -----Original Message----- From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of John M. Formsma Sent: Tuesday, November 14, 2006 9:27 PM To: Pianotech List Subject: Piano Disc pedal mechanism problem Piano Disc in a 1995 Young Chang G-150. (I'm assuming the PD system is about as old as the piano.) When the system is playing the piano, the sustain pedal makes a knocking sound. It's more like wood-on-wood or wood-on-metal than a clicking metal-on-metal type sound. The pedal doesn't have this noise during normal human play. I know little about PD systems except for the obvious things like reinstalling actions, basic electronics, etc. After 15 minutes of peering, replacing a worn felt, and head-scratching, I told the owner I'd ask others rather than learning with her $$. As far as I can tell, the problem is not in the "actuator" that engages the pedal. (I did replace the felt under the actuator rod, so that can be ruled out as a source of noise.) The noise seems to come more from the rod that goes up from the PD pedal bracket into the action cavity. There is a rubber washer under the nut on the threaded rod that could be worn, but since I don't have those, I didn't attempt a replacement. Moving the PD pedal bracket slightly did lessen the noise, so I'm wondering if something is out of alignment. But nothing looked obvious. Anyone know what this noise might be from, and how to tell a non-PD tech how to fix it? Thanks, John Formsma
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