Methods for locating MCA board faults

The MCA board failed to scan the spectrum during a site deployment.
MCA monitors 80 channels of four ports. All 320 channels reported the CHAN_LOS alarm.
1. No input optical signal on all four ports of the MCA board.
2. The MCA board was faulty.

Root cause:


1. Detect the R01, R02, R03, and R04 ports of the MCA boards using a power meter and optical spectrum analyzer, and each port had optical power and normal waveforms were observed from the analyzer.
2. Use the following NE commands to check whether the configurations were correct:
:cfg-set-monwave:bid,1,cband,1&&80,enable; (Channel 1 is used as an example, other channel can be used as well.)
:cfg-verify; (Verification must be performed.)
:cfg-get-analydata:bid,1; MAC optical spectrum analysis data query
Query results of ":cfg-get-analydata:bid,1; MAC optical spectrum analysis data query" for all channels were ?600, meaning that there were no optical signals on any ports.
3. According to previous steps, the MCA board was faulty. The board was unplugged for further analysis.
a. Open the fireproof board.
b. The module with five fibers at the front of the board is the optical switch. Among the five fibers, the white one is for input, which connects to the front panel; and the blue one is for output.
Remove the end with the white fiber of the blue monolithic fiber adapter that is fixed on the board, input optical signals to any one of the R01 to R04 ports, and use the power meter to determine whether the blue fiber has output.
When there is no output, confirmed whether the input is normal. If normal, then the optical switch or the fiber adapter is damaged.
c. When there is output, confirm whether the OCM (optical spectrum analysis module) is faulty.
Re-insert the end with the white fiber, and remove the end with the blue fiber. Connect the white fiber to the MON port of other boards, and make sure that the MON port has OTU wavelength and the fiber connection is correct. Reinsert the board to the subrack.
After the board starts running, run the commands for optical port enabling, verifying, and wavelength analyzing. If the queried result of the MCA is still ?600, then the optical spectrum analysis module, the software, or the NE is faulty.
For damaged optical switches or faulty optical spectrum analysis modules, replace the board.

Suggestion and conclusion:
To locate MCA faults, first confirm whether there are input optical signals, then confirm whether the data configurations are correct, and finally confirm whether the hardware is faulty.

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