i have problem in the CPU 1511-1 PN  

the CPU power off now 

i want to fix this problem 

i connect external power to the CPU not power up also 

what i should do now to know the reason for the failure 

how to be sure that the CPU defected 

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Split from Tia portal v16 & CPU 1511-1PN.

Hi hossam eldeps,

If your CPU never turns on, no matter what power supply is connected, then it is definitely defective. You can send it to Siemens for identification and potential repair of the defect. Otherwise, you can simply replace it with a new one.

Kind regards
Stefan