Replacing a TX Matrix Three-Input 240-A DC Power Supply

1. Removing a TX Matrix Three-Input 240-A DC Power Supply
2. Setting the Input Mode Switch on a Three-Input 240-A DC Power Supply for the TX Matrix Router
3. Installing a TX Matrix Three-Input 240-A DC Power Supply
4. Connecting DC Power to a TX Matrix Replacement Three-Input 240-A DC Power Supply
5. Powering On a Replacement TX Matrix Three-Input 240-A Power Supply

Removing a TX Matrix Three-Input 240-A DC Power Supply

1. Switch off the external circuit breakers to the power supply being removed. Make sure that the voltage across the DC power source cable leads is 0 V and that there is no chance that the cables might become active during the removal process.
2. Attach an electrostatic discharge (ESD) grounding strap to your bare wrist, and connect the strap to one of the ESD points on the chassis.
3. Switch the circuit breakers on the power supply faceplate to the off position (O).

   Note: After powering off a power supply, wait at least 60 seconds before turning it back on.

4. Remove the clear plastic cover protecting the terminal studs on the faceplate.
5. Using a 7/16-in. (11 mm) nut driver or wrench, remove the nuts and washers from the terminal studs (see Figure 1).

   Caution: You must ensure that power connections maintain the proper polarity. The power source cables might be labeled (+) and (–) to indicate their polarity. There is no standard color coding for DC power cables. The color coding used by the external DC power source at your site determines the color coding for the leads on the power cables that attach to the terminal studs on each power supply.

   Figure 1: Disconnecting Power Cables from the DC Power Supply

   
6. Remove the cable lugs from the terminal studs.
7. Loosen the captive screw or screws on the cable restraint on the right edge of the power supply faceplate.
8. Carefully move the power cables out of the way.
9. Loosen the captive screws on the lower corners of the power supply faceplate completely.
10. Twist the ejector handles on the upper corners of the faceplate counterclockwise to unseat the power supply.
11. Grasp the handle on the power supply faceplate and pull firmly. Slide it halfway out of the chassis (see Figure 3).

    Caution: Each three-input 240-A DC power supply weighs approximately 25 lb (11.3 kg). Be prepared to support the full weight of the power supply as you remove it from the router.

12. Place one hand underneath the power supply to support it, and slide it completely out of the chassis.

    Warning: Do not touch the power connectors on the rear of the power supply (see Figure 2). They can contain dangerous voltages.

    Figure 2: Rear of the Power Supply Showing Midplane Connectors

    

Figure 3: Removing a Three-Input 240-A Power Supply

Setting the Input Mode Switch on a Three-Input 240-A DC Power Supply for the TX Matrix Router

Note: Do not set the input mode switch if the power supply is installed in the chassis. If the power supply is already installed, you must disconnect all cables and remove the power supply before setting the input mode switch.

1. Using a screwdriver, loosen the captive screw holding the metal cover over the input mode switch (see Figure 4).
2. Rotate the metal cover away from the input mode switch to expose the switch.
3. Check the setting of the input mode switch. Use a flashlight, if necessary. In 2-INPUT mode, the switch must be located all the way to the right.
4. If the input mode switch is not set correctly, use a sharp, nonconductive object to slide the switch all the way to the right to set the power supply to 2-INPUT.

   Caution: Do not use a pencil, because fragments can break off and cause damage to the power supply.

5. Rotate the metal cover over the input mode switch, and use a screwdriver to tighten the captive screw.

Figure 4: Three-Input 240-A DC Power Supply

Installing a TX Matrix Three-Input 240-A DC Power Supply

1. Make sure that the voltage across the DC power source cable leads is 0 V and that there is no chance that the cables might become active during installation.
2. Attach an electrostatic discharge (ESD) grounding strap to your bare wrist, and connect the strap to one of the ESD points on the chassis.
3. Switch the circuit breakers on the power supply faceplate to the OFF position (O).
4. Using both hands, slide the power supply into the chassis until you feel resistance (see Figure 5).
5. Twist the ejector handles at the upper corners of the power supply faceplate clockwise until they stop.
6. Tighten the captive screws at the lower corners of the power supply faceplate to secure the power supply in the chassis.

Figure 5: Installing a Three-Input 240-A Power Supply

Connecting DC Power to a TX Matrix Replacement Three-Input 240-A DC Power Supply

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.
2. Verify that a licensed electrician has attached cable lugs to the power cables that you supply.
3. Verify that the voltage across the DC power source cables leads is 0 V and that there is no chance that the cables might become active during installation. If needed, switch off the customer site circuit breakers.
4. Verify that the circuit breakers on the power supply faceplate are in the OFF position (O).
5. Remove the clear plastic cover protecting the terminal studs on the faceplate.
6. Remove the nut and washer from each power terminal stud.

   Caution: You must ensure that power connections maintain the proper polarity. The power source cables might be labeled (+) and (–) to indicate their polarity. There is no standard color coding for DC power cables. The color coding used by the external DC power source at your site determines the color coding for the leads on the power cables that attach to the terminal studs on each power supply.

7. Secure the cable lugs to the terminal studs, first with a washer, then with a nut (see Figure 6).
   1. Attach the positive (+) DC source power cable lugs to the RETURN (return) terminals.
   2. Attach the negative (–) DC source power cable lugs to the –48V (input) terminals.

   Use a 7/16-in. (11 mm) nut driver or wrench to tighten the nut. Apply between 23 lb-in. (2.6 Nm) and 25 lb-in. (2.8 Nm) of torque to each nut.

   Note: For power supplies set to 2-INPUT mode (required for the T640 router and TX Matrix router), connect two DC power cables, one for RETURN and one for –48 V to INPUT 0 and two DC power cables, one for RETURN and one for –48 V to INPUT 1.

   Note: INPUT 0 and INPUT 1 on the three-input 240-A DC power supply in slot PEM0 must be powered by dedicated power feeds derived from feed A, and INPUT 0 and INPUT 1 on the three-input 240-A DC power supply in slot PEM1 must be powered by dedicated power feeds derived from feed B. This configuration provides the commonly deployed A/B feed redundancy for the system.

8. Loosen the captive screw or screws on the cable restraint on the right edge of the power supply faceplate.
9. Route the DC power cables through the cable restraint.
10. Tighten the cable restraint captive screw or screws to hold the power cables in place.
11. Verify that the power cabling is correct, that the power cables are not touching or blocking access to other hardware components, and that they do not drape where people could trip on them.
12. Replace the clear plastic cover over the terminal studs on the faceplate.

Figure 6: Connecting Power Cables to the Power Supply

Powering On a Replacement TX Matrix Three-Input 240-A Power Supply

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.
2. Switch on the customer site circuit breakers to provide voltage to the DC power source cables.

   Note: If the system is completely powered off when you power on the power supply, the Routing Engine boots as the power supply completes its startup sequence. If the Routing Engine finishes booting, you must power off the system before you power on again. After powering off a power supply, wait at least 60 seconds before turning it back on.

3. Verify that the INPUT PRESENT LEDs on the power supply faceplate are lit steadily, indicating that the inputs are receiving power.
4. Switch the circuit breakers on the power supply to the ON position (|).

   Note: After a power supply is powered on, it can take up to 60 seconds for status indicators—such as the LEDs on the power supply, the command output displays, and messages on the LCD display on the craft interface—to indicate that the power supply is functioning normally. Ignore error indicators that appear during the first 60 seconds.

5. Verify that the CB ON LEDs on the power supply faceplate are lit steadily, indicating that the circuit breakers are on.
6. Verify that the DC OK LED on the power supply faceplate is lit steadily, indicating that the power supply is correctly installed and is functioning properly. The DC OK LED blinks momentarily, then lights steadily.