Problem Description

SYN_BAD alarm is reported by a Metro1000 equipment network element of a bureau, and the alarm disappears after changing the clock tracking to the internal clock. Initially, it is judged to be the failure of the main control board, and after replacing the main control board and resuming the clock tracking, the SYN_BAD alarm is still reported. 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

SYN_BAD, POWER_FAIL

Processing

1. Check the network management operation log to confirm that no one operated the device 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 to the internal clock after the SYN_BAD alarm disappeared, apply for time to replace the main control board to restore the previous clock tracking, SYN_BAD alarm re-reported;

4、Check the alarm settings of network elements in the network management, and found that the Power_fail alarm is blocked, and the corresponding alarm is reported after opening it.

5, 155622H the core power of the entire system (including +12V, -12V, +5V ) are generated by the power board MB2 unified in the box, and -5V is -12V converted to the SCB board. For +5V, there are two -48 to +5V power supply 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 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 is 2102110511P036000206, corresponding to the factory time in June2003, 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 phase-locked loop application on the SCB board, and the phase-locked loop handles the clock tracking function of the equipment. In the case of ±12V voltage failure, the phase-locked loop works abnormally, resulting in abnormal clock tracking function of the network element. At the same time, since the -5V voltage is converted from -12V, in the case of -12V failure -5V power supply also fails accordingly, the official phone abnormal.

The SS44MB2 has two types of single boards, VER.0 and VER.B. The VER. 0 single board has two kinds of single boards. For SS44MB2 with VER.0, the ±12V power supply fails because of the ±12V power supply chip failure. For VER.BSS44MB2, 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 Metro1000 generates 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 main control board or the box failure, 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.

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The technical information in this chapter and the related SDH equipment troubleshooting process are provided by Shenzhen Optical Transmission Network Technology Co. Huawei SDH optical transmission equipment, SDH transmission equipment sales phone: 13430988088 Welcome to call!