Power Supplies
The type 8641 server is shipped with a primary power supply. An additional or optional power supply can be added to the computer. Connectors are used to transfer the primary power supply voltages and signals from the primary power supply to the optional power supply. The following illustrations show how the two power supplies are connected.

NOTE: When replacing the primary power supply cover plate, rotate the plate 180 Degrees. (This will leave an opening for the primary power supply connector cable that connects to the optional power supply.) Failure to do so will cause the power supply connector cable to be crimped when the plate is replaced.



NOTE: Tabs are located on the side of each power supply to secure them together.

Primary Power Supply Voltages
If the voltages are correct, and the power supply fan runs, the power supply is OK.

Optional Power Supply Drive Connector Voltages

If the voltages are correct, and the power supply fan runs, the power supply is OK.

If the power supply shuts down, or appears to fail at power-on, you might have one of the following problems:

• Too many devices are set to start instantly, see " Setting The Motor-Start Jumper".
• There are too many large-capacity devices installed. The nominal operating current of the devices installed collectively exceeds the available current of the power supply. See the 'Personal System/2 Installation Planningï guide (form number G41G-2927) for more information.

ATTENTION: Unplug the power cord and wait two minutes before checking voltages to give the power supply capacitors time to discharge.

On some models, there is an access-cover fan (to cool the processor). If that fan does not work, you have one of the following problems:

• No power to the fan: 12 V dc (? 1.4 V dc) required at the two fan cable pins on the base.
• Defective J28 cable (check cable continuity)
• Defective fan. (To test the fan, use a two-wire jumper to connect the fan terminals to the cable pins on the base.)
• Defective system board.

NOTE: Verify that the voltage-select switch (if applicable) is set for the correct voltage. If the voltages are correct, and the Symptom-to-FRU index does not solve the problem, go to 'Undetermined Problems'.