ADTRAN 25 manual Fan Assembly Trouble

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Fan Assembly Trouble

The fans should always be operating when the system is receiving ac power and the cabinet switch is turned on. If the fans are not operating, be sure that the system is receiving ac power.

if the system is receiving power and the fans are still not operating, the ac power connection to the fan assembly is faulty or the fans themselves are faulty (for example, burned out motors).

To check the ac power connection to the fan assembly, first unplug the power cord, and then remove the four No. 6-32 screws at the corners of the assembly. Carefully lift the fan assembly away from the cabinet. Check the two modular plugs attached on the left side of the assembly. If the plugs are securely attached, the fan assembly itself is faulty and must be replaced.

To replace the fan assembly, remove the modular plugs at the left side of the assembly. Reconnect these plugs to a known good fan assembly, and reinstall the new fan assembly by setting it in place in front of the power supply and replacing the four No. 6-32 screws at the corners of the assembly. (Without fans, the power supply will overheat and the system will automatically shut down.)

Danger: Whenever the power supply shuts itself down (due to

overheating, shorting, etc.), unplug the power cord and

wait at least 5 minutes before restoring power.

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