IBM XSERIES 255 TYPE 8685, Hardware Maintenance Manual And Troubleshooting Manual

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v
Always look carefully for possible hazards in your work area. Examples of these
hazards are moist floors, nongrounded power extension cables, power surges,
and missing safety grounds.
v
Do not touch live electrical circuits with the reflective surface of a plastic dental
mirror. The surface is conductive; such touching can cause personal injury and
machine damage.
v
Do not service the following parts with the power on when they are removed from
their normal operating places in a machine:
– Power supply units
– Pumps
– Blowers and fans
– Motor generators
and similar units. (This practice ensures correct grounding of the units.)
v
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 guide
The intent of this inspection guide is to assist you in identifying potentially unsafe
conditions on these products. Each machine, as it was designed and built, had
required safety items installed to protect users and service personnel from injury.
This guide addresses only those items. However, good judgment should be used to
identify potential safety hazards due to attachment of non-IBM features or options
not covered by this inspection guide.
If any unsafe conditions are present, you must determine how serious the apparent
hazard could be and whether you can continue without first correcting the problem.
Consider these conditions and the safety hazards they present:
v
Electrical hazards, especially primary power (primary voltage on the frame can
cause serious or fatal electrical shock).
v
Explosive hazards, such as a damaged CRT face or bulging capacitor
v Mechanical hazards, such as loose or missing hardware
The guide consists of a series of steps presented in a checklist. Begin the checks
with the power off, and the power cord disconnected.
Checklist:
1. Check exterior covers for damage (loose, broken, or sharp edges).
2. Turn off the computer. Disconnect the power cord.
3. Check the power cord for:
a. A third-wire ground connector in good condition. Use a meter to measure
third-wire ground continuity for 0.1 ohm or less between the external ground
pin and frame ground.
b. The power cord should be the appropriate type as specified in the parts
listings.
c. Insulation must not be frayed or worn.
4. Remove the cover.
5. Check for any obvious non-IBM alterations. Use good judgment as to the safety
of any non-IBM alterations.
Appendix B. Related service information
169