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This chapter describes periodic maintenance procedures, troubleshooting procedures, and the replacement of major parts for the Release 4.1 MGX 8220.
 | Caution For protection against shock hazard, verify both power cords are disconnected before servicing unit. |
| Caution Vergewissern sie sich, däss beide Netzkäbel vom Gerät getrennt sind, bevor Sie mit den Wärtungsärbeiten beginnen. |
| Caution Pour iviten tout danger, dibrancher les deux cordons d'alimentation avant toute intervention de maintenance sur cet equipement. |
Most monitoring and maintenance of the MGX 8220 shelf is done via the operating system software. Preventive maintenance of the MGX 8220 shelf hardware is minimal and requires the following:
1. Periodically check the node supply voltage and internal cabinet temperature. The temperature should not exceed 50ºC.
2. Periodically check the event log with the dsplog command.
3. Periodically check the network alarm status with the dspalms command.
4. Ensure that the cooling unit intake grills and the exhaust plenum are clear.
This section describes basic troubleshooting steps to be taken for some of the more obvious node failures. (Refer to Table 8-1.) This is not an exhaustive set of procedures, and does not take into account any of the diagnostic or network tools available to troubleshoot the MGX 8220 shelf. Refer to Chapter 5, "Service Configuration ", for information on commands and command usage.
The MGX 8220 shelf run self tests continuously to ensure proper function. When the unit finds an error condition that affects its operation, it downs the card or line that is affected. If it is caused by a card failure and there is a redundant card, the failed card is downed and the standby card becomes the active card.
The FAIL lights on the cards indicate that the system has found these cards defective in some mode, and now considers them as failed cards. Refer to Table 8-1 to find the cause and obtain information on replacing the failed component.
| Symptom | Probable Cause | Remedy |
|---|---|---|
No front panel LEDs are lighted. | Circuit breakers on the MGX 8220 shelf Power Entry Module(s) switched off. | Press in the black button on power entry modules to switch on circuit breakers. If problem persists, pull all cards and power supplies out to see if a shorted card or supply exists. |
| The MGX 8220 shelf power cord plug disconnected from AC supply. | Reconnect power cord. |
Card front panel fail LED lit | Card failed self-test. | Check status of card at control console using dspcds screen. If alarm is confirmed, try card reset (resetcd command). Finally, remove and replace the card. |
Card stby LED on. | Card is off-line. | Not a problem as long as a primary card is active. |
BNM major or minor LED on. | Service-affecting (major) or non-service affecting (minor) system fault. | Check event log to identify problem reported. |
| Network trunk failed. | Observe Port LEDs on each BNM. |
| Internal temperature is higher than normal resulting from blocked air flow or defective fan. | Check front of cooling assembly for freedom of air flow. Replace the assembly that may have failed or slowed. Check free air flow in plenum chamber, remove blockage if necessary. |
ASM hist LED lit. | If no other alarm indications, a fault occurred in the past but has been cleared. | Press ASM history clear button. Check NMS event log to determine cause. |
BNM Port LED is red. | Trunk is in local or remote alarm. | Use short BNM loopback cable line module connector for local test of trunk. Loop trunk at DSX-3 crossconnect to check cable. |
ASC fail LED flashing | Downloading system software or configuration data. | Wait for download to complete. |
After an alarm occurs, use the MGX 8220 shelf software to isolate the problem. If an MGX 8220 shelf part has failed, it must be replaced.
| Caution Only authorized personnel should remove and replace parts on the MGX 8220 system. |
Parts should be replaced personnel who have taken Cisco training courses or have been trained by a qualified system manager. For assistance in diagnosing or replacing a failed part, call a Cisco representative.
Save the electrostatic bag, foam, and carton. These packaging materials are needed to return the failed part to Cisco.
This section describes how to replace an MGX 8220 front card.
The MGX 8220 shelf front cards are:
| Caution Ground yourself before handling the MGX 8220 shelf cards by placing a wrist strap on your wrist and clipping the wrist strap lead to the cabinet. |
When a card has failed, the red FAIL light for that card turns on. Before replacing it, check to see if the card needs to be reseated and check that the appropriate back card is correctly installed. After reseating the card, wait for it to run its self-tests to see if the ACTIVE light comes on. If the card is seated correctly, but the FAIL light is still on, replace the card.
When replacing a card that has no redundant equivalent, the service provided by that card will be disrupted. Replacing a non-redundant ASC or BNM card will bring down the entire shelf. Replacing a FRSM card will bring down the channels that are serviced by that card.
To remove a front card:
Step 2 Gently pull the card out of the card cage.
To install a front card:
Step 2 Gently slide the card all the way into the slot and press the retaining tab until it snaps into the vertical position.
Back cards are retained through two screws: one at the top of the faceplate and one at the bottom of the faceplate. Back cards contain very few active components (if any) and rarely need replacing.
To remove a back card:
Step 2 Use a flat screwdriver to undo the two retaining screws in the back card's faceplate.
Step 3 Pull the two extraction levers into the horizontal position. This will start the card extraction.
Step 4 Gently pull the card out of the card cage.
To install a back card:
Step 2 Position the rear card guides over the appropriate slot at the top and bottom of the card cage.
Step 3 Gently slide the card all the way into the slot and tighten the two captive screws on the back card's faceplate. Tighten the upper and lower screws alternately to prevent mis-alignment of the card. Do not overtighten. Tighten the screws to secure the card.
 | Warning Cards must be inserted in the correct slot positions. This is particularly true with back cards. If service module back cards are inserted into slots intended only for ASC and/or BNM back cards (slots 1, 2, 3, and 4) damage to the card and backplane can result. If you accidentally attempt to insert a service module back card into slots 1, 2, 3, or 4 and have difficulty in operating the shelf, examine the backplane pins and the connector on the wrongly inserted back card to see if they have been bent or damaged. |
DC Power Entry Modules (PEM) contain few active components so they should rarely need replacement. Access is from the back of the shelf. To remove a PEM, proceed as follows:
Step 2 Disconnect the 48VDC power cable from the module.
Step 3 Pull out the power entry module from its slot.
Step 4 Slide in the replacement module until its connector seats in its socket.
Step 5 Replace the 48VDC power cable.
Step 6 Press the black button on the power entry module until it latches in the IN position.
To replace the assembly:
Step 2 Remove the screws attaching the assembly to the rack.
Step 3 Pull the assembly out of the rack.
Step 4 Slide the new assembly into the rack.
Step 5 Use the screws to attach the assembly to the rack.
Step 6 Reconnect the cables from the shelf or other modules to the new assembly.
| Warning If you replace the cooling assembly with power applied to the shelf, you must work quickly to prevent heat buildup in the shelf which could damage the cards. |
Posted: Mon Jan 15 16:38:56 PST 2001
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