Maintenance

Removing and Replacing the Fan Tray Assembly

Removing and Replacing an AC Power Supply Module

Removing and Replacing a DC Power Entry Module

Removing and Replacing Processor and Service Modules

Changing a Single-Height Card Slot into a Double-Height Card Slot

Backplane Fuse Replacement

Bit Error Rate Testing (BERT) Through an MGX-SRM-3T3

Pattern Test Options

Loopback Test Options

Maintenance

This section provides maintenance procedures for the physical components of the MGX 8230. It includes:

This section does not include detailed troubleshooting information for the MGX 8230 as an IGX feeder. That information will be found in other documentation.

Removing and Replacing the Fan Tray Assembly

The Fan Tray Assembly, shown in Figure 4-1, can be removed and replaced when an MGX 8230 is running if it is done very quickly. When the MGX 8230 is running you must remove and replace the Fan Tray Assembly in less than two minutes. Individual fans in the Fan Tray Assembly are not field replaceable.

The Fan Tray Assembly is vertically installed on the left side of the front of the MGX 8230 chassis. It is held in place by one captive screw on its bottom; there is also an ejector lever on the bottom of the Fan Tray Assembly that can be used to unseat it from the backplane.

Caution Because of its shape, the Fan Tray Assembly has a tendency to drop suddenly against the chassis as it is being removed. Be sure to hold it with two hands and hold it firmly until it is completely removed from the chassis.

Figure 4-1: Fan Tray Assembly

Once you have determined that a Fan Tray Assembly is faulty, follow these steps to remove and replace it:

Note Make sure that you have the replacement Fan Tray Assembly and your tools ready.

Step 1 Open the MGX 8230 door, if applicable, and locate the Fan Tray Assembly, shown in the left side of the MGX 8230 chassis as seen from the front. See Figure 4-2.

Step 2 Loosen the captive screw holding the Fan Tray Assembly to the MGX 8230 chassis.

Step 3 Use the ejection lever added to the bottom of the fan and chassis to unseat the Fan Tray Assembly from the backplane.

You can use the combination tool used to open the door that is provided with the MGX 8230 or a regular screwdriver for leverage on the injector. Slip it through the opening in the ejector lever and pull the lever out away from the MGX 8230.

Step 4 Pull the Fan Tray Assembly out carefully, holding it firmly with two hands so it does not drop suddenly against the MGX 8230 chassis as it is removed.

There is a small standoff on the upper-left side of the chassis that the Fan Tray Assembly rides on that helps support it as it is being removed, but you must still be careful.

Figure 4-2: Fan Tray Assembly in MGX 8230 Chassis

To replace the Fan Tray Assembly, follow these steps:

Step 1 Slide the replacement fan into the MGX 8230 chassis; make sure to get the upper left edge of the Fan Tray Assembly over the small standoff on the upper left wall of the card cage in the fan slot.

Step 2 Carefully press it until the plug on the rear of the Fan Tray Assembly mates with the connector on the backplane of the MGX 8230.

Step 3 Tighten the captive screw securing the fan to the MGX 8230 chassis.

Removing and Replacing an AC Power Supply Module

There can be up to two 1200 Watt AC Power Supply Modules installed in the AC Power Supply Tray. The optional AC Power Supply Tray is factory installed. Each AC Power Supply Module has its own Enable (On/Off) switch, connectors, and status LEDs. The AC Power Supply Modules are independent of one another, and one can be replaced while the other powers the MGX 8230.

Figure 4-3 illustrates a rear view of an AC Power Supply Module. Figure 4-4 illustrates the rear panel of an MGX 8230 with two AC Power Supply Modules installed. There is a captive nut on the flange on the top of the rear panel of each AC Power Supply Module used to secure the AC Power Supply Modules to the AC Power Supply Tray and the MGX 8230 chassis, once they are installed.

Figure 4-3: AC Power Supply Module, Rear View

Figure 4-4: MGX 8230 with Two AC Power Modules Installed

The AC power supply is defective if the front panel AC LED is on, but the DC LED is off with the DC output cable connected to the backplane and the power supply. To verify that the power supply did not latch off due to an AC input line transient, turn off the enable switch, wait for at least four seconds, and turn the enable switch on again. If the DC LED fails to light, the power supply is defective.

After determining that an AC power supply is faulty—the front panel AC LED is on, but the DC LED is off -- follow these steps to remove and replace it:

Step 1 Turn off the Enable (On/Off) switch on the appropriate AC Power Supply Module.

Step 2 Turn off power at the AC source for the appropriate AC Power Supply Module.

Step 3 At the rear of the MGX 8230, disconnect the AC power cord from the AC input of the appropriate AC Power Supply Module by loosening the st4rain relief clamp screw with the multi tool provided.

Step 4 Disconnect DC power cable from the appropriate AC Power Supply Module.

Step 5 Remove the screw at the top of the AC Power Supply Module that secures it to the AC Power Supply Tray.

Step 6 Pull AC Power Supply Module out using the handle on rear of the AC power supply as shown in Figure 4-3.

Step 7 Insert the new AC Power Supply Module.

Step 8 Replace and tighten the screw at the top of the AC Power Supply Module.

Step 9 Reattach the DC power cable.

Step 10 Reattach the AC power input cable.

Step 11 Turn the AC source power on.

Step 12 Turn the Enable switch on the AC Power Module to On.

Step 13 From the front of the MGX 8230, verify that both LEDs (AC and DC) on the replacement AC Power Supply Module are lit.

Removing and Replacing a DC Power Entry Module

There can be two DC PEMs located on the rear panel of an MGX 8230. Once you have determined that you need to remove and replace a DC PEM, shown in Figure 4-5, follow these steps:

Figure 4-5: DC Power Entry Module

Removing DC PEM

To remove a DC PEM, follow these steps:

Step 1 Turn off the circuit breaker on the DC PEM that is being removed.

Step 2 Turn off the DC source power.

Step 3 Turn off the switch on the DC PEM.

Step 4 Unplug the pluggable terminal block at TB1.

Step 5 Loosen the captive screws holding the DC PEM to the MGX 8230.

Step 6 Slide the DC PEM out of the MGX 8230.

Replacing DC PEM

To replace a DC PEM, follow these steps:

Step 1 Turn off the circuit breaker on the DC PEM that is being replaced.

Step 2 Slide the DC PEM into its slot on the back of the MGX 8230.

Step 3 Secure the DC PEM to the MGX 8230 with the two captive screws.

Step 4 Plug the pluggable terminal block back in at TB1.

Step 5 Turn on the power at the DC source.

Step 6 Turn on the DC PEM switch.

Step 7 Verify that the DC PEM LED is lit.

Removing and Replacing Processor and Service Modules

Removing and Replacing Processor and Service Modules is covered in Chapter 2 in the section, "Installing Processor and Service Modules." Those procedures include instructions for both front cards and back cards.

Changing a Single-Height Card Slot into a Double-Height Card Slot

Note Even though the card slots in an MGX 8230 are horizontal and would be more appropriately called single-width and double-width, this manual still refers to the card slots as single-height and double-height. This is because the MGX 8230 processor and service module cards are a subset of the MGX 8850 cards, which are installed vertically in an MGX 8850 chassis.

The MGX 8230 is typically configured at the factory as you ordered it. Unused card slots are configured for single-height modules and covered with blank faceplates.

Single-height service module slots 3 through 7 and 10 through 14 can be converted into slots for a double-height by removing the center divider module. Note that these slots have to be converted from bottom to top, that is, slot 3 has to be converted before you convert slot 4. Figure 4-6 illustrates the slot numbering of an MGX 8230 with slots 3 configured for a double-height module.

Figure 4-6: MGX 8230 Slot Numbering

Be aware of the following before you convert the slots:

Convert lower number slots first. Slot 3 must be converted before slot 4 can be converted, and so on.

After conversion, the left slot, which identifies both single-height and double-height slots, is numbered from the left-side. Thus slot 4 could refer to either a single-height slot or a double-height slot. The right slots are numbered on the right side, as shown in Figure 4-6, and refer only to single-height slots.

Caution You can convert single-height card slots to double-height when there is powered applied to the MGX 8230. Install the center guide module only in the center of the card slot where there is a guide which it fits over and slides on. The guide is on the top of the card slot in the middle. Make sure never to slide the center guide module into the backplane connectors.

Figure 4-7 illustrates a center guide module, and Figure 4-8 shows the location of center guide modules in an MGX 8230 chassis.

Figure 4-7: Center Guide Module, Slot Divider

Figure 4-8: Front View of an MGX 8230 Card Cage

To convert a slot, follow these steps:

Step 1 Delete all the connections, and down all the ports, lines, and trunks on the single-height slots that you are converting, if applicable.

Step 2 Remove the cabling from the back cards (unless they are the correct back cards for the double-height card), then remove the back card.

Step 3 Remove the front cards in both single-height slots, if applicable.

Step 4 Repeat steps 3 and 4 for every slot you are going to convert.

Step 5 Insert a screw driver and loosen the long screw that holds in the center guide module in place. See Figure 4-7.

Step 6 Remove the center guide module by sliding straight out on guide rail.

Step 7 Install the double-height front card and associated back cards as needed.

Install a blank faceplate where you do not fill a double-height slot with a double-height card. (Likewise, where you do not install a back card, you must install a blank single-height faceplate.)

To replace a center guide module, follow these steps:

Step 1 Locate and prepare the empty slot in which you are going to install the center guide module.

Step 2 Note the position for the center guide module in marked by an indentation on the bottom panel of the card slot, and there is a guide for the slot fixed to the top panel of the card slot.

Step 3 Slide the center guide module into the card slot, making sure that it rides on the guide fixed to the top panel.

Caution Install the center guide module only in the center of the card slot where there is a guide that fits over and slides on. The guide is on the top of the card slot in the middle. Make sure never to slide the center guide module into the backplane connectors.

Step 4 When the guide is all the way in position, insert a screw driver in the hole located at the front of the center guide module and tighten the long screw.

When reconverting slots to single height, start at the top and work down.

Backplane Fuse Replacement

The MGX 8230 has fuses in the backplane to protect individual card slots. Backplane fuses on the MGX 8230 rarely, if ever, need replacement. These fuses, which are shown in Figure 4-9, are accessed from the rear of the card cage. They require a special tool for removal and replacement and should be changed by certified field personnel only.

Backplane fuses are intended to prevent catastrophic damage to the backplane in the event of accidental shorting of -48 VDC on the backplane to chassis ground. This type of event could be caused by bent backplane pins, contact of conductive elements (EMI Cans, EMI Gaskets, and so on) to power pins. These events would most likely happen during a factory build.

Because of design constraints, these fuses need to be in sockets on the backplane and are therefore not readily accessible.

If a bad card slot is verified, call Cisco TAC. If a card with an open fuse is verified, return it to Cisco.

Warning Replacing a fuse requires Cisco personnel only using a special tool with the power off.

Figure 4-9: Backplane Fuses

Bit Error Rate Testing (BERT) Through an MGX-SRM-3T3

The MGX 8230 feeder can perform a bit error rate test (BERT) on an active line or port. This type of testing disrupts service because a BERT session requires the tested path to be in loopback mode. In addition, the pattern test replaces user-data in the path with the test pattern. The applicable line types and variations for a DS1 are:

A T1 or E1 line
Fractional portions of a T1 line that add up to a DS1
A single 56Kbps or 64Kbps DS0
A DS0 bundle consisting of N x 64-Kbps DS0s

With a set of MGX-SRM-3T3/B cards in the system, you can initiate a BERT session on an MGX-FRSM-2CT3 or any 8-port service module. (In contrast, the MGX-FRSM-2T3E3, MGX-CESM-T3, and MGX-CESM-E3 do not use the MGX-SRM-3T3/B for BERT. See the sections for these service modules in this chapter for applicable BERT.)

The MGX 8230 bus structure supports one BERT session, so the feeder can run a maximum of one session at a time. When you specify the target slot through the CiscoView application or the CLI, the system determines if a BERT configuration already exists in the MGX 8230. After the system determines that no BERT configuration exists, the display presents a menu for the BERT parameters.

The CLI commands (whose functions correspond to CiscoView selections) are:

cnfbert to configure and start a test
modbert to inject errors into the BERT bit stream
dspbert to display the parameters and results of the current test
delbert to end the current test

Note When a BERT session begins, all connections on a line or port go into alarm and return to normal when the test ends. Consequently, the test may result in other types of traffic (such as AIS).

During configuration, the parameter display or menu items depend first on the card type and whether the test medium is a physical line or a logical port. Subsequent choices are test type, test patterns, loopback type, and so on. See the Cisco MGX 8000 Series Command Reference for details on cnfbert and the other BERT commands. The concatenation of menu to menu is extensive, so this section contains tables of menu selections based on the card types and the test type.

The test type can be pattern, loopback, or DDS seek. The choice of test type leads to further menu displays. Following the tables of menu choices, the remaining sections define the parameters in these menu choices.

For AX-FRSM-8T1, AX-CESM-8T1, and MGX-FRSM-2CT3, see Table 4-1 pattern tests and Table 4-2 for loopback tests.
For AX-FRSM-8E1 and AX-CESM-8E1, see Table 4-3 for pattern tests and Table 4-4 for loopback tests.
For MGX-AUSM-8T1, see Table 4-5 for pattern tests and Table 4-6 for loopback tests.
For MGX-AUSM-8E1, see Table 4-7 for pattern and Table 4-8 loopback tests.

Table 4-1: Pattern Test for AX-FRSM-8T1, AX-CESM-8T1, and MGX-FRSM-2CT3

Test Medium Medium Type Device to Loop BERT Pattern

Port

Port with N time slots (can also submit to the DDS seek test)

v54

all patterns

Port with one 64-Kbps time slot (can also submit to the DDS seek test)

latch or v54

all patterns

Port with one 56-Kbps time slot (can also submit to the DDS seek test)

noLatch

latch or v54

29 or 211

all patterns

Line

n/a

in-band/ESF or metallic

all patterns

Test Medium	Medium Type	Device to Loop	BERT Pattern
Port	Port with N time slots (can also submit to the DDS seek test)	v54	all patterns
Port with one 64-Kbps time slot (can also submit to the DDS seek test)	latch or v54	all patterns
Port with one 56-Kbps time slot (can also submit to the DDS seek test)	noLatch latch or v54	29 or 211 all patterns
Line	n/a	in-band/ESF or metallic	all patterns

Table 4-2: Loopback Test for AX-FRSM-8T1, AX-CESM-8T1, and MGX-FRSM-2CT3

Test Medium Medium Type Loopback

Port

Port with N timeslots (can also submit to the DDS seek test)

far end or remote

Port with one 64Kbps time slot (can also submit to the DDS seek test)

far end or remote

Port with one 56Kbps time slot (can also submit to the DDS seek test)

far end or remote

Line

n/a

metallic, far end, or remote

Test Medium	Medium Type	Loopback
Port	Port with N timeslots (can also submit to the DDS seek test)	far end or remote
Port with one 64Kbps time slot (can also submit to the DDS seek test)	far end or remote
Port with one 56Kbps time slot (can also submit to the DDS seek test)	far end or remote
Line	n/a	metallic, far end, or remote

Table 4-3: Pattern Test for AX-FRSM-8E1 and AX-CESM-8E1

Test Medium Medium Type Device to Loop BERT Pattern

Port

any

none

all patterns

Line

n/a

metallic

all patterns

Test Medium	Medium Type	Device to Loop	BERT Pattern
Port	any	none	all patterns
Line	n/a	metallic	all patterns

Table 4-4: Loopback Test for AX-FRSM-8E1 and AX-CESM-8E1

Test Medium Medium Type Loopback

Port

any

remote loopback

Line

n/a

metallic or remote

Test Medium	Medium Type	Loopback
Port	any	remote loopback
Line	n/a	metallic or remote

Table 4-5: Pattern Test for MGX-AUSM-8T1

Test Medium Medium Type Device to Loop BERT Pattern

Line

n/a

in-band/ESF

all patterns

Test Medium	Medium Type	Device to Loop	BERT Pattern
Line	n/a	in-band/ESF	all patterns

Table 4-6: Loopback Test for MGX-AUSM-8T1

Test Medium Medium Type Loopback

Line

n/a

far end, remote, or metallic

Test Medium	Medium Type	Loopback
Line	n/a	far end, remote, or metallic

Table 4-7: Pattern Test for MGX-AUSM-8E1

Test Medium Medium Type Device to Loop BERT Pattern

Line

n/a

none

all patterns

Test Medium	Medium Type	Device to Loop	BERT Pattern
Line	n/a	none	all patterns

Table 4-8: Loopback Test for MGX-AUSM-8E1

Test Medium Medium Type Loopback

Line

n/a

remote or metallic

Test Medium	Medium Type	Loopback
Line	n/a	remote or metallic

Pattern Test Options

The pattern test options consist of the device to loop and the pattern. This section lists the device options and patterns that appear in the menus. Refer to the preceding tables as needed. The device to loop options identify the type of device that participates in the test:

noLatch is a device that does not latch the data. It can be a:
- Non-latching office channel unit (OCU) that consists of one device
- Non-latching OCU that consists of a chain of devices
- Non-latching channel service unit (CSU)
- Non-latching data service unit (DSU)
Latch is a device that can latch the data and can be a:
- Latching DS0-DP drop device
- Latching DS0-DP line device
- Latching office channel unit (OCU)
- Latching channel service unit (CSU)
- Latching data service unit (DSU)
- Latching HL96 device
in-band/ESF
v54 is a polynomial loopback
metallic is a local loopback within the service module and does not involve an external device

The available patterns are:

1. All 0s

2. All 1s

3. Alternating 1-0 pattern

4. Double 1-0 pattern

5. 215-1 pattern

6. 220-1 pattern

7. 220-1 QRSS pattern

8. 223-1 pattern

9. 1 in 8 pattern

10. 3 in 24 pattern

11. DDS-1 pattern

12. DDS-2 pattern

13. DDS-3 pattern

14. DDS-4 pattern

15. DDS-5 pattern

16. 29 pattern

17. 211 pattern

Loopback Test Options

The loopback tests do not monitor the integrity of the data but rather the integrity of the path. The type of loopback indicates the direction of test data transmission. The choices are:

far end means the service module transmits data to the CPE and receives the data back
remote means the service module receives data from the CPE and loops back to the CPE
metallic means the service module receives data from the network and loops it back to the network

Table of Contents

Maintenance

Removing DC PEM

Replacing DC PEM