IBM 2254 Hardware Maintenance Manual

Also see for 2254: Hardware Maintenance Manual User guide

Contents

Chapter 9. Related service information 203Observe the special safety precautions when you work with very high voltages;these instructions are in the safety sections of maintenance information. Useextreme care when measuring high voltages.• Regularly inspect and maintain your electrical hand tools for safe operationalcondition.• Do not use worn or broken tools and testers.• Never assume that power has been disconnected from a circuit. First, check that ithas been powered-off.• Always look carefully for possible hazards in your work area. Examples of thesehazards are moist floors, nongrounded power extension cables, power surges,and missing safety grounds.• Do not touch live electrical circuits with the reflective surface of a plastic dentalmirror. The surface is conductive; such touching can cause personal injury andmachine damage.• Do not service the following parts with the power on when they are removedfrom their normal operating places in a machine:— Power supply units— Pumps— Blowers and fans— Motor generatorsand similar units. (This practice ensures correct grounding of the units.)• If an electrical accident occurs:— Use caution; do not become a victim yourself.— Switch off power.— Send another person to get medical aid.Safety inspection guideThe intent of this inspection guide is to assist you in identifying potentially unsafeconditions on these products. Each machine, as it was designed and built, hadrequired safety items installed to protect users and service personnel from injury. Thisguide addresses only those items. However, good judgment should be used toidentify potential safety hazards due to attachment of non-IBM features or options notcovered by this inspection guide.If any unsafe conditions are present, you must determine how serious the apparenthazard could be and whether you can continue without first correcting the problem.Consider these conditions and the safety hazards they present:• Electrical hazards, especially primary power (primary voltage on the frame cancause serious or fatal electrical shock).• Explosive hazards, such as a damaged CRT face or bulging capacitor• Mechanical hazards, such as loose or missing hardwareThe guide consists of a series of steps presented in a checklist. Begin the checks withthe power off, and the power cord disconnected.Checklist:1. Check exterior covers for damage (loose, broken, or sharp edges).2. Power-off the computer. Disconnect the power cord.