Piano Action Problems Explained

The piano action is a mechanical system of around 7,500 moving parts. When any part fails, goes out of adjustment, or is damaged by humidity, specific symptoms appear. Here are the most common piano action problems, what causes them, and what they cost to repair in Singapore.

Double Striking (One Key Press Produces Two Notes)

Cause: The repetition spring or the jack is out of adjustment. When you press a key, the hammer is thrown at the string, should bounce back, and the escapement mechanism resets it for the next strike. If the let-off is set too close, the hammer bounces back and fires again before it has fully reset — producing a double sound.

Fix: Regulation — specifically adjusting let-off, repetition spring tension, and check height. Part of a full action regulation (S$200–S$700) or targeted regulation of affected notes (S$80–S$150).

Ciphering — A Note Sounds Continuously

Cause: The damper is stuck in the raised position, or the damper felt has warped (from humidity) so it no longer seals against the strings. When a damper does not rest correctly on its strings, the string vibrates every time any note is played (sympathetic resonance).

Fix: Re-seat the damper guide, replace the damper felt, or re-regulate the damper. Cost: S$60–S$200 per damper depending on type (upright vs grand, bass vs treble).

Silent Key — No Sound When Key Is Pressed

Cause: Several possibilities — a broken hammer shank (the hammer does not travel to the string), a disconnected or broken jack, a broken string (the string is simply not there to vibrate), or in severe cases, a structural failure in the key itself.

Fix: Diagnose the specific cause first. Broken hammer shank: replace the shank (S$20–S$60 per hammer). Broken string: single string replacement S$30–S$80. Broken jack or repetition lever: replacement of the part and regulation.

Heavy or Uneven Touch

Cause: Action regulation has drifted — key heights, hammer travel distances, and escapement points vary across the keyboard. In Singapore's humidity, felt parts absorb moisture and change thickness, altering all regulated measurements. An unregulated piano feels heavy on some notes, light on others, and inconsistent throughout.

Fix: Full action regulation (S$200–S$500 for upright, S$400–S$700 for grand). All 30+ regulated dimensions per note are set to manufacturer specifications.

Key Slow to Return (Not the Same as Sticky)

Cause: A broken or weak repetition spring (different from a stuck key bushing). The key goes down quickly but rises very slowly, making rapid passages difficult. Most apparent in fast repeated notes.

Fix: Spring replacement or tensioning. On a grand piano, the repetition spring is part of the repetition lever mechanism and its adjustment is a normal part of grand regulation. Cost: S$10–S$30 per spring or included in full regulation.

Buzzing or Rattling on Specific Notes

Cause: A loose action part (free-floating hammer, detached flange), a broken string coil vibrating against the plate, or a loose internal component rattling at the resonant frequency of a specific note. Can also be a loose nameplate, lid, or external component.

Fix: Inspection to locate the source, then targeted repair. Some buzzes are easy to find and fix in minutes; others require removing the action entirely.