IBM 7012 G Series, Service Manual

Page: 30 / 264

Reference Information
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7. Check for alterations or attachments. If there are any, check for obvious safety hazards
such as broken wires, sharp edges, or broken insulation.
8. Check the internal cables for damage.
9. Check for dirt, water, and any other contamination within the system unit.
10.Check the voltage label on the back of the system unit to ensure that it matches the
voltage at the outlet.
11. Check the external power cable for damage.
12. With the external power cable connected to the system unit, check for 0.1 ohm or less
resistance between the ground lug on the external power cable plug and a jack screw on
the parallel port connector.
Parallel Port (P1)
Adapters
Power Cord
Receptacle
Power Control
Port (RS-485)
Mouse Port
9-Pin Serial Port (S3)
25-Pin Serial Ports (S1/S2)
Rear
Fan
Keyboard Port
13. If the system unit passes the test in the previous step, install the covers.
14. Check each external device that has its own power cable:
a. For damage to the power cord.
b. For the correct grounded power cable.
c. With the external power cable connected to the device, check for 0.1 ohm or less
resistance between the ground lug on the external power cable plug and the metal
frame of the device.