HARPSICHORD TROUBLE SHOOTING


This list attempts to start with the most frequent concerns first and respond to them by order of frequency and reversibility. If the possible remedy calls for something that is not easily reversed and you are not sure of what you are doing, it is probably best to call in somebody more experienced before possibly creating more problems.

I Note not sounding:

    A. String is broken or out of position
    B. Key not returning fully
      1. key mortise too tight around balance pin or guide pin
      2. key rubbing against adjacent key (in front or in back. In the back, watch out for expanding lead weights - the white lead oxide powder can absorb through the skin and through breathing it)
    C. Plectrum may be broken off too short
    D. Jack not dropping completely, but key works OK
      1. Jack too tight in upper or lower mortise
      2. Jack binding against gap spacer underneath registers
      3. Rear register jack binding against overrail (if present)
      4. Top of jack caught by misaligned jackrail
      5. Plectrum not able to return under string
        a. Damper set too low
        b. Jack set too tall
        c. Plectrum too long
        d. Hook on tip of plectra hanging onto string
        e. Tongue not returning fully
          1. weak spring
          2. tongue rubbing on jack body
        f. Tongue spring too strong
II A note does not damp after key is released
    1. Damper missing or set too high
    2. Key not returning to full rest (see I B)
    3. Jack not dropping completely, but key works OK (see I D)
    4. Notch worn in damper by string
IV Many notes do not damp after keys are released
    1. Humidity decrease has shrunk case and lowered strings away from dampers
    2. Soundboard distortion has lowered strings away from dampers
    3. Dampers are loose and knocked out of adjustment
IV Inconsistent repetition
    1. Key not operating freely (see I B)
    2. Jack not always dropping fully (see I D)
    3. Jack too loose in register - jack or register may need to be shimmed
    4. Plectrum too short - push through and adjust, or replace and voice
    5. Spring on tongue too weak
    6. Plectrum not always getting under string (see I D 3)
V Excessive string breakage
    1. Pitch of instrument is too high for string design (common among harpsichords built in this century by copying the antiques, but which used modern pitch, or an incorrect old pitch, instead of the pitch the antique was designed for)
    2. Wrong wire material being used 
    3. String wound over itself around the tuning pin 
    4. Bruised or damaged wire 
    5. Poorly made hitchpin loop
    6. Tuning pins are being turned excessively when tuning
    7. Increased humidity caused the instrument to go too sharp
VI Overall pitch keeps going flat, and the humidity is not dropping
    1. Case is distorting from structural problem
    2. Soundboard is distorting
    3. Hitchpin rails are loose and moving away from case sides
VII A single note, or several separated notes, keeps going flat
    1. Poorly made hitchpin loop may be slipping
    2. Loose tuning pin may be turning in its hole
    3. The winding on an antique pin might have lost its grip
VIII Note buzzes
    1. Sympathetic vibration of hitchpin end of string against hitchpin rail
    2. Strings touching soundboard or 4’ bridge due to soundboard distortion
    3. A neighboring jack is within vibrating range of the plucked string
    4. The plucking jack is set too high so the plectrum is too close to the string at rest
    5. A string sympathetic to the one being plucked has its jack damper out of position and its plectra to close to the string
    6. A broken length of string is touching the vibrating string
IX Registers don’t turn on or off properly
    1. Register ends (Capstan screws, buttons or shims) not adjusted properly
    2. Stoplever pivot screws too loose allowing register springback
    3. Stoplever does not have enough range of motion
    4. Dampers falling in front of strings may be pushing register back
    5. Registers are binding in the gap
    1. registers have swollen from excessive humidity
    2. excessive string tension, or structural problems, have tightened the gap
    3. gap spacers were not installed properly to hold the gap open
X Uneven feel when playing one register at a time
    1. Voicing of plectra is uneven, in length, width, thickness, and/or angle
    2. Keys are unevenly weighted
    3. Some keys or jacks are sticking or binding (see I B or I D)
XI Uneven feel when playing more than one register, but OK when played singly Plucking order is not set correctly XII Uneven feel when playing a double-manual coupled, but OK when separated Height of coupler dogs not set properly XIII Upper manual plays well when uncoupled, but does not damp properly when coupled Height of coupler dogs too tall XIV Coupler on double-manual difficult to operate
    1. Check for obstructions
    2. Both excessive dryness and excessive humidity can bind the sliding parts
    3. Coupler dogs too tall
XV   Keydip is too deep or too shallow (5/16" is about right for harpsichords; a little less 
        for single register instruments, upper manuals of doubles, and some Italians, some-
        times a little deeper is needed in the extreme bass of large harpsichords with three
        or more sets of strings)
    1. Check that jacks are not set too low so that the plucking starts later than necessary
    2. Check position of jackrail if that is what regulates the motion
    3. Check overrail at back of keyframe if that is what regulates the motion
    4. Adjustments may have to be made to front keyrail if that is what stops the key
    5. Felt may have compacted from use
9/02/99

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