RMA Checklist

Checklist Before Submitting an RMA Request

Based on prior experience, a short troubleshooting session may reveal the root cause of a failure and prevent redundant shipment of parts.Dragon Well provides the below checklists for common issues of our products, and updates the checklists regularly, based on our customers' feedback and our continued experience.

Dragon Well Fiber Optic Transceiver Diagnostic Checklist

Step 1: Physical Connection Verification

➠ Action:

  • Re-seat transceiver firmly into the device port.

  • Confirm audible click indicating full insertion.

Step 2: Configuration Cross-Check

ParameterTransceiver ATransceiver B
Type (e.g., SFP28)Must matchMust match
Data RateMust matchMust match
WavelengthMust matchMust match
Port Settings*IdenticalIdentical
*Includes FEC, Auto-negotiation, Duplex Mode

➠ Cable Compatibility:

  • Single-mode fiber ↔ 1310/1550nm transceivers

  • Multi-mode fiber ↔ 850nm transceivers

  • DAC/AOC cables ↔ Matching interface types

Step 3: Device Interface Diagnosis

➠ Procedure:

  1. Access device CLI/GUI (e.g., show interfaces).

  2. Check for error flags:

    • RX Loss / TX Fault

    • Module Not Supported

  3. Critical Alert:

    "UNSUPPORTED TRANSCEIVER" = Compatibility issue

Step 4: DDM Parameter Validation

Acceptable Ranges:

ParameterMinMax
Temperature-5°C+75°C
Voltage3.13V3.47V
TX PowerSee datasheet
RX Power> Receiver sensitivity
➠ Note: Copper RJ45 & Media Converters lack DDM.

Step 5: Optical Signal Troubleshooting

Link Loss Budget Formula:

Maximum Allowable Loss (dB) = TX Power (dBm) - Receiver Sensitivity (dBm)

Debug Sequence:

  1. 󠀠󠀠Clean: Use LC/SC fiber cleaner on transceiver ports & cable ends.

  2. 󠀠󠀠Test: Measure end-to-end loss with optical power meter.

  3. 󠀠󠀠Swap:

    • Try known-working port on same device

    • Replace with same Dragon Well P/N from original order

    • Use verified optical cable

Diagnostic Flow: Port Insertion → Configuration → Signal Verification

DAC & AOC Cable Checklist

1. If the DAC & AOC cable isn’t recognized by the switch or link’s errors, plug and unplug the cable again, and make sure that it is correctly inserted into the port of the designated device.

2. For directly connected cables, check the data rates configured, duplex, FEC function, and Auto-negotiation mode of the ports that the cables are connected are identical.
For breakout cables, check whether the duplex, FEC functions, and Auto-negotiation status of the ports that the cables are connected are identical. 

Check whether the 40G or 100G port is configured as Breakout mode.

3. Log in to the management interface of the device that the cable is connected and check whether there is an error message after the cable is inserted.If there is an error message, it indicates that the cable is faulty or is not compatible with the device.
 
4. Check whether the light of the port that the cable is connected is normal. If not, please perform the following:
  • Repeat the test after plugging the cable into another known working port.
  • Repeat the test after replacing other cables with the same P/N from the same Dragon Well order.

Network Interface Card Checklist

1. If the card isn’t recognized by the OS, reseat the card in the server PCI slot, and verify that the card is recognized by the OS.

  • In Linux based OS: lspci | grep –i net
  • In Windows OS:
    Under “Device Manager-> Network Adapter”, check it. If you cannot find the network card, click “Action-> Scan for hardware changes”.

2. Verify that the card driver version is up to date. If not, please install the latest version.

3. Please use a known working cable to connect network card and switch, verify the physical connectivity, and check whether the port works normally.

Note: Read ports LEDs indication – Is it in a faulty state? (A stay-on green light means normal.)

4. Communication test, please use the known working cable to connect network card and switch, then test in the same leaf.

5. Repeat the test after replacing another known working network card.
Note: If the issue recurs with the known working card, it is most likely that the network card bought is not faulty.

Network Switch Checklist

Switch Power Supply and Fan FRU (Field Replacement Unit) Checklist

1. Check whether the power supply and the PDU is working well.
Read the Power Supply/Fan LED indication.

Are the LEDs indicating a faulty state?

2. Verify that the FRU module is working normally by invoking the following commands:
  • For S58xx Series Switch:
    Switch#show environment—Check the running state
  • For Nxxxx Series Switch:
    Cumulus@switch:~$ sudo smonctl—View sensor information for various system units
    Cumulus@switch:~$ sensors—Check the running state of the hardware

3. Replace another available power supply and PDU, and exchange a known working FRU with the defective FRU for testing.

4. Read the power/fan LED indicator, and check if the indicator is stay-on green.

5. Repeat the test in STEP2. to verify if the FRU module is working normally.

Log In Checklist

1. If you encounter a problem that you cannot log in to the switch by using the console cable, please perform the following:

  • Verify that the computer has installed the driver successfully. Then the corresponding communication port (COM X) can be seen under the device manager > port option after the console cable is plugged into the computer.
  • Verify that the console cable is properly connected to the switch console port.
  • Set the correct parameters on SecureCRT, refer to the following:
  • Replace the connected console cable with another known working cable, and verify whether you can log in with the working cable.
  • Verify whether the control software is working well. Putty or Xshell is recommended by FS.

2. If you encounter a problem that you cannot log in to the switch remotely through the admin port or plain port, please perform the following:

  • Please confirm whether the switch management port IP address, vlanif IP address and PC IP address can be pings normally. It is recommended to directly connect the switch and PC for ping test.
  • Replace the network cable with another known working cable to connect the switch and the PC.
  • Ensure whether the switch has HTTP, HTTPS, Telnet, and SSH enabled.
  • Try changing the browser to login.

Ports Checklist

1. If you encounter problems with ports not working properly, please perform the following:

  • Replace the connected cables with another known working cable.
  • Connect the cables to another known working port.
  • Check the port configuration to see if the port is activated. If not, please activate the port by invoking the command: no shutdown.
  • Perform a loopback test by connecting the faulty ports to another known working port in the same leaf.
  • Read ports LEDs indication. Check if the LED indicator is stay-on green.
  • Please perform the communication testing: Connect two switches with a working cable, then configure the ports of both switches to the same network segment for testing.

2. If the cable or transceiver is not working because the date rate of the port doesn’t match, please perform the following:

  • Verify the cable or transceiver has the same data rate with the ports.
  • Note: if the cable or transceiver data rate is 1G while the switch port is 10G, it is recommended to set the port of 10G switch to 1G rate mode and then perform the test again.
  • Perform a loopback test to ensure there is no incompatibility problem.
  • Read ports LEDs indication. Check if the LED indicator is stay-on green.

Mux Demux & OADM Checklist

1. If you don’t know how to connect, learn the using instructions for different types of products. Please refer to the following:
  • Single/Dual Fiber CWDM MUX/DEMUX
  • Single/Dual Fiber CWDM MUX/DEMUX
  • Single/Dual Fiber CWDM OADM
  • Single/Dual Fiber CWDM OADM
2. Check whether the adapter is loose at the connection point and the end surface is clean.
 
3. Check the insertion loss of the MUX/DEMUX channel port.

Monitor Online Software Checklist

1. Install the matching SQL Server database, about specific operation please refer to:
 
2. Check whether the SQL Server database can be connected normally and whether the configuration manager is running.
 
3. Check if the information of Monitor Online connection interface is filled in correctly.
 
4. Whether the localhost address and NMU IP can be pinged.
   

If the localhost IP can be pinged, check whether the server name format of the SQL Server database is the same as the localhost address, or you can copy the server name content in the SQL Server database to the localhost address directly.

5. Use Simple Management Tool to see if it can be managed.

FMT Pluggable Module Checklist

1. If the Pluggable Module isn’t recognized, please perform the following:
  • Check whether the Power and Run lights of the Pluggable Module are normal.
  • Use Monitor Online Software and Simple Management Tool for login Management to check whether the Pluggable Module information can be monitored.
  • Check whether the Pluggable Module information can be viewed on the display screen of the NMU main control card.
  • Re-insert the defective Pluggable Module or re-start the Fiber Enclosure for testing.
  • Place the defective Pluggable Module into other card slots of the Fiber Enclosure to see if it can be monitored.
  • Place the defective Pluggable Module into other Fiber Enclosures to see if it can be monitored.
2. Check whether the reading data of the Pluggable Module is abnormal or not. If so, please refer to Format Setting of Decimal Point.
 
3. Check if there is an alarm on the Pluggable Module indicator:
  • Check if the indicator light on the Pluggable Module is red.
  • Use Monitor Online or Simple Management Tool to manage and read the Monitor information on the Pluggable Module interface to see if the information is abnormal.
  • If it is an input-output alarm, connect the input side light of the Pluggable Module to the optical power meter to check whether the input optical signal is normal.
  • If it is EDFA Pluggable Module, check whether the Pump light source of EDFA is turned off.
  • Repeat the test after replacing other items with the same P/N from the same Dragon Well order.
4. Check whether the module can funcion well on the Pluggable Module:
  • Use the module on the switch to see if the module can function well.
  • After inserting the module, observe whether the indicator light below the corresponding port of the OEO Pluggable Module is always on.
  • Check whether the module information can be monitored on the display of the Simple Management Tool, Monitor Online, and NMU main control card.
  • Use the defective module in other good combination ports of the OEO Pluggable Module to see if it can be monitored.
  • Place the defective module on other OEO Pluggable Modules to see if it can work normally.

Fiber Optic Patch Cable Checklist

1. In case you encounter an issue associated with link’s bring-up or link’s errors, check if there are any physical damages to the product first.
 
2. Understand the precautions about matching different cables to other products.
 
3. Repeat the test after connecting to another known working port.
 
4. Repeat the test after replacing another cable with the same P/N in the same Dragon Well order.
Note: If this cable can work well, it is most likely that the previous one is defective.

Fiber Cassette & Enclosure Checklist

1. For fiber cassette or enclosure, if don’t work on the connection, please check if there are any physical damages to the product first.
 
2. Check if the overall connection of the product meets the regular configurements
   

You may learn more about regular connection and polarity.

3. Check if the cables and transceivers connected to the cassette/enclosure work fine (referring to their respective Checklists).
 
4. Repeat the test after replacing another cassette & enclosure with the same P/N in the same Dragon Well order.
Note: If this cassette & enclosure can work well, it is most likely that the previous one is defective.