Key chatter or simply chatter is an undesirable phenomenon when a single key press results in multiple registered inputs. As an example, typing the word 'Deskthority' on a keyboard with a defective 'K' key suffering from chatter may yield the result 'Deskkthority'.
There are several reasons for key chatter listed below, with proposed solutions:
Bad solder joint
Mechanical key switches are soldered to printed circuit boards. A badly made solder joint could break and then intermittently not conduct electricity, with the symptom being key chatter.
This is often the result of a "cold solder joint": If the solder pad and switch pin had not been sufficiently heated before solder was applied, the solder had not bonded with both of them properly.
This cause of key chatter is more frequently observed on DIY-keyboards that people have soldered themselves, but has also been observed on mass-produced keyboards.
The solution is to redo the soldering joint.
All key switches with conductive contacts exhibit contact bounce for a very short amount of time, each time a key is pressed. This is normal, and is filtered out by a debouncing algorithm in the keyboard controller. However, key chatter will occur if a switch has become defective in a way that makes it exhibit contact bounce for a longer duration than intended.
Some makes of switches could have the occasional defective switch, and some types of switches are known to start chattering more easily than others,
There are suggested methods for remedying key chatter in defective switches, including the use of compressed air, although they are not universally recommended. Elitekeyboards.com strongly advises against this practice in the Support section of their website; however, they currently do not supply any information about what might happen to the keyboard if such actions are attempted, nor a preferred alternative.
A sure solution is to replace the defective switch.
- Elitekeyboards.com - Support page with key chattering/bouncing description