Keyboard Failure – Symptoms and Troubleshooting Introduction Keyboards (Fig. 20-1) are the classic input device. By manipulating a matrix of individual electrical switches, commands, and instructions can be entered into the computer one character at a time. If you’ve used computers or typewriters to any extent, you already have an excellent grasp of keyboard handling. However, keyboards are not without their share of drawbacks and limitations. Although today’s keyboard switches are not mechanically complex, there area number of important moving parts. When you multiply this number of moving parts times the 80 to 100+ keys on atypical keyboard, you are faced with a substantial number of moving parts. A jam or failure in anyone of these many mechanical parts results in a keyboard problem. Most keyboard failures are hardly catastrophic, but they can certainly be inconvenient. This chapter gives you the information needed to understand and repair computer keyboards.