Symptoms
- The key goes down and comes back up but no note sounds
- The note is very faint, or you hear a thud or click instead
- The note sounds only when you play hard or only softly
- Nearby notes play normally
Likely causes
Broken hammer shank or flange
The thin wooden shank holding the hammer can crack, or the flange that holds it to the action can break or come loose, so the hammer never reaches the string.
Hammer not resetting
If the jack does not return under the hammer, a broken spring or misadjusted part, the key moves but the hammer does not fire on the next stroke.
Broken string
In the bass a note has one or two strings, so a broken one can make it silent. In the treble the note may get quieter rather than silent.
Obstruction
A pencil, toy or loose part lying in the action can block the hammer's path.
Damper or felt problem
Rarely, a damper that does not lift, or a loose felt, mutes the string.
What you can safely check yourself
- 1On an upright, open the top lid, or on a grand, open the main lid, and watch the hammer while slowly pressing the dead key.
- 2If the hammer does not move at all, the problem is between the key and the action; if it moves but stops short, look for something blocking it.
- 3Look at the strings for that note for a visibly broken or curled string.
- 4Check whether the soft pedal or a practice rail (middle pedal on many uprights) is engaged; a felt muffler can make notes very quiet.
What not to do
- Do not reach into the action while pressing keys hard; hammers move fast and can be damaged.
- Do not try to glue a broken hammer shank with household glue in place; it usually needs to be removed and properly repaired or replaced.
- Do not pull on a broken string; the end is sharp and under tension.
Quick fixes vs. call a pro
You can usually handle it
- Disengaging the practice rail or soft pedal
- Removing a visible object from the action
- Identifying whether hammer or string is the issue
Call a technician
- Broken or loose hammer, shank or flange
- Broken string
- Hammer does not reset after each stroke
- Several dead notes at once
What a technician will do
A technician replaces or re-glues the broken shank or flange, re-pins loose parts, adjusts the jack spring, or replaces the broken string. Most single dead notes are fixed in one visit in about 30-60 minutes; a new bass string may need a follow-up tuning as it settles.
A piano holds about 18–20 tonnes of string tension. If a fix means opening the action, turning tuning pins or working near the strings, leave it to a technician.