• Supported Platforms
• T640 Routers

• Related Topics
• T640 SONET Clock Generators (SCGs) Description
• T640 SONET Clock Generators (SCGs) LEDs
• Maintaining the T640 SCGs

Installing a T640 SCG

To install a replacement SCG (see Figure 1):

1. Attach an electrostatic discharge (ESD) grounding strap to your bare wrist, and connect the strap to one of the ESD points on the chassis. For more information about ESD, see T640 Preventing Electrostatic Discharge Damage.
2. Carefully align the sides of the SCG with the guides in the SCG slot.
3. Grasp the SCG by its handle, and slide it straight into the chassis until it contacts the midplane.
4. Tighten the captive screws on the corners of the SCG faceplate.
5. To bring the SCG online, press the online/offline button until the green OK LED lights.
6. To verify that the SCG is installed correctly and is functioning normally, check the LEDs on the SCG faceplate. The green OK LED should light steadily. If the SCG is master, the blue MASTER LED should also light steadily.

   To check the status of the SCGs, use the following CLI command:

   
   

   user@host> show chassis environment scg

   For more information about using the CLI, see the Junos OS manuals.