2.6 TC-A2107 The Device Fails to Be Powered On Because the MOS Transistor Is Faulty

Publication Date:  2012-07-18 Views:  108 Downloads:  0
Issue Description
Related information about the product and version: the T3200 and T3500 G2.
After a device on a certain site has been running for a period, power it off and then on. The black screen occurs, the system power indicator on the front panel of the enclosure is off, and the running/alarm indicator of the power module on the rear panel of the enclosure is green on continuously.

Log in to the ISM. From the navigation tree, choose Device Management > Sensors, as shown in Table 2-1.
Table 1-1  Sensors
ID Name Value Status
6 VTT_CPU0 0V Critical
7 VTT_CPU1 0V Critical
8 DDR3_1V5_CPU0 0V Critical
9 DDR3_1V5_CPU1 0V Critical
10 DDR3_0V75_CPU0 0V Critical
11 DDR3_0V75_CPU1 0V Critical
12 IOH_1V1 0V Critical
13 VCCP_CPU0 0V Critical
14 VCCP_CPU1 0V Critical
15 CPU0_1V8 0V Critical
16 CPU1_1V8 0V Critical
17 ICH_1V5 0V Critical
18 ICH_1V1 0V Critical
19 IOH_1V8 0V Critical
20 BAT_3V 3.17V Normal
21 Var_5V 0V Critical
22 Var_3V3 0V Critical
23 USB_DDR3_12V1 0V Critical
52 VCC_5V 0V Critical
53 POWR_IOH1V1 Disabled Disabled
Alarm Information
Handling Process
Step 1     Power off the device.      
Step 2    
Disconnect the AC power supply.
Step 3     Remove the disk module and power module, and record the disk sequence.
Step 4     Replace the enclosure.
 Step 5     According to the sequence recorded in Step 3, insert the disk module and power module in the new enclosure.                              
tep 6    
Power on the device.


Root Cause
1.         If the system power indicator is off, it indicates that the device is not powered on.
2.         If the running/alarm indicator of the power module is green on continuously, it indicates that the power modules are working normally.
3.         If critical is displayed in the sensor list, it indicates that voltage of some power supply is abnormal and the device enters the protection state.
In addition, the MOS transistor of power chip LGATE of DDR3_1V5_CPU0 is faulty.