SILBERMANN GRAND PIANO REGULATION PROCEDURES
 

1.  KEYFRAME

Check strike point and adjust the limiter screws in end dags accordingly.  Remove the action stack and replace frame in the keyboard in order to check the following:

A. The right (treble) edge of each key should be flush with the right (treble) edge of each damper underlever.  This is to prevent double damper lift when the shift pedal is engaged fully.

B.  Adjust the key bedding bolts using strips of newspaper and recheck after stack is returned to frame.

C. Check for tight/loose keys. Ease and space if necessary.

Replace the action stack and check the following:

D. The distance from the keybed to the hammer flange center = 151 mm.

E. The distance from the keybed to the wippen flange center = 86 mm

G. Check level of keyframe by knocking to find high areas, then sanding if necessary. Do not sand the keybed to take care of this problem.  Sand the frame.

2.  KEY HEIGHT

A. The distance from the keyboard to the top of the white key = 66 mm

B.  The distance from the top of the black key to the top of the white key = 12 mm.

3.     HAMMER TO STRINGS

A. The hammer blow distance - 46 mm

B.  Travel the hammers, paper where necessary.

C.  Align and space hammers uniformly for squarely striking the strings.  In the capo area, check the string spacing.

4.  CHECK ALL POINTS OF FRICTION

Possible friction hazards can arise in the areas of: action centers, keystick clearances (eliminate splinters), loose leads coming out of keys, hammer heads rubbing against each other, and tight key bushings.

5.  WIPPENS

A.  Align wippens squarely under the knuckles. Travel the wippens if necessary.

B.  Jack is to be centered in the cradle window.  Correct bad ones by bending the center pins.

C.  Align rear edge of jack to be flush with the rear edge of the wood knuckle insert.  Needle overly hard knuckles and lube (baby or talc powder) all noisy knuckles.  Check for jack cheating.

D.  Adjust the repetition lever so that the jack is 0.1 to 0.2 mm below the top of the lever.

6.      LET-OFF

A.  Bass Section (Keys 1 to 43)  2.5 mm
B.  Treble Section (Middle section) 2.0 mm
C. Treble Section (Upper keys to Key 88) 1.5 mm

7.   KEY DEPTH

A. White key dip = 10.2 mm
B.  Black keys are regulated to stop 2.0 mm above white keys at rest and according to the necessary after-touch.
C. Adjust key dip +0.2mm or -0.5 mm to satisfy the necessary after-touch demand.

8.  HAMMER DROP

A. Regulate the drop screws so hammers crop according to the corresponding amount of let-off

9.  BACK CHECKS

A. Align back checks to be squared with the hammer tails.
B.  Hammers check at 16 mm. Back checks should not be closer than 3 mm away fro hammer tails at rest position.

10.  REPETITION SPRINGS

Adjust the repetition spring tension by tightening or easing the coil. The hammer should rise from check position on slow release of the key in a strong but controlled non-jumping movement.  Do not put bends in the springs.  Re-check the repetition lever adjustment by winking the jacks.

11.  DAMPERS

A.  The dampers should begin to lift when hammer has travelled 20 to 21 mm. Dampers must comletely clear the strings when keys are fully depressed and/or when the sustain pedal is fully engaged.

B. The distance between the damper up-stop rail and damper underlever when key is in full depression is 1 mm.  Test with a black key in each section.

C. Check for damper efficiency, proper seating and string follow.  There must be a slight amount of lost motion in the sustain pedal when making these checks.

12.     PEDALS

A.  Adjust damper pedal for 2 mm of lost motion. All dampers must be regulated for uniform lift when pedal is engaged. Check for sufficient clearance when pedal is fully depressed.

B.  The sostenuto rod should be adjusted so that the tabs are about 1 mm away. Test the sostuneto function by using the sustain pedal.

C.  Adjust the screw in the treble cheek block so that the shift action is properly goverend. The keyframe should stop when the treble hammers are directly under the right two strings of each unison. Test by muting the speaking string(s) of each unison and by playing.