Description of the problem

Metro1000 transmission equipment network element reported SYN_BAD alarm, after changing the clock tracking to internal clock alarm disappeared, initially judged to be the fault of the main control board, after replacing the main control board to restore the clock tracking still reported SYN_BAD alarm. Check the alarm settings and found that the power_fail alarm was blocked, and then canceled the blocking of the power_fail alarm reported, judged to be a failure of the chassis, replace the chassis and the main control to solve the problem.

Alarm information

Metro1000 transmission equipment SYN_BAD, POWER_FAIL

Processing

1. Check the network management operation log to confirm that no one operated the equipment through the network management at that time;

2、Check that the clock tracking is set correctly and there is no relevant alarm on the corresponding line side;

3, reset the clock tracking for the internal clock after the SYN_BAD alarm disappears, apply for time to replace the main control board to restore the previous clock tracking, SYN_BAD alarm re-reported;

4, in the network management check network element alarm settings, found that the Power_fail alarm is blocked, open the corresponding alarm reported.

5, 155622H the core power supply of the entire system (including +12V, -12V, +5V) are generated uniformly by the power board MB2 in the box, and -5V is -12V converted to the SCB board. For +5V, there are two -48 to +5V power modules on the power board, one of which is the primary and one is the backup.

6, POWER_FAIL alarm parameter meaning:

+5V alarm 0x1;

+5V alarm alternate channel 0x7;

-5V alarm 0x2;

+12V alarm 0x3;

-12V alarm 0x4;

Battery dead alarm 0x5.

7, according to the current POWER_FAIL alarm parameter judgment, Metro1000 equipment -5V and -12V power supply failure, and -12V is generated by the MB2 power supply board in the box, -5V by -12V conversion. From this judgment, the frame power supply failure is the most likely, replace the frame after the corresponding failure to solve.

8, the device's bar code 2102110511P036000206, corresponding to the factory time in June 2003, the current equipment has been working for 10 years, there is a case of aging electronics.

Root cause

The power supply board provides ± 12V voltage to the SCB board phase-locked loop application, phase-locked loop processing equipment clock tracking function, in the case of ± 12V voltage failure, phase-locked loop work abnormally, resulting in abnormal clock tracking function of network elements. Meanwhile, since the -5V voltage is converted from -12V, in the case of -12V failure -5V power supply also fails accordingly, and the official telephone is abnormal.

The SS44MB2 has two types of single boards, VER.0 and VER. For SS44MB2 with VER.0, the ±12V power supply fails because of the ±12V power supply chip failure. For VER.B SS44MB2, the ±12V power supply failure is due to the aging and failure of capacitors C18 and C19, resulting in the burning of fuse F4 and F5.

Recommendations and summary

When generating this kind of alarm, first check whether the power_fail alarm is blocked, if it is blocked, cancel the setting, check the corresponding alarm parameter, confirm whether it is the fault of the main control board or the box, and quickly locate and deal with it.

Due to the aging of electronic devices, the failure rate will increase after a certain period of time, so it is recommended to use new products to replace them.

The relevant technical information in this chapter and the SDH equipment troubleshooting process are collected and organized by Shenzhen Optical Transmission Network Technology Co. ( www.opticaltrans.com), please retain the reproduction! Our company specializes in the sale of Huawei SDH optical transmission equipment, SDH transmission equipment.