Fault on 300 PLC

[finskhan]

now a days i am facing a aproblem with a 313C PLC siemens that sometime my PLC haung all LEDs are ON.what can be the problem?i go to diagnostic buffer but it does not leave any alarm.it does not go in Run Mode even if I change the Mode from PLC Slector switch.First i will Power off and Power On then i goto Stop mode and now when i change the Mode from Selector switch then i goto Run Mode and will be in normal operation.
it can be a supply problem?or something else?

 

[bkottaras]

now a days i am facing a aproblem with a 313C PLC siemens that sometime my PLC haung all LEDs are ON.what can be the problem?i go to diagnostic buffer but it does not leave any alarm.it does not go in Run Mode even if I change the Mode from PLC Slector switch.First i will Power off and Power On then i goto Stop mode and now when i change the Mode from Selector switch then i goto Run Mode and will be in normal operation.
it can be a supply problem?or something else?

From the sound of it, faulty CPU.
I'd replace it with a new one.

 

[clemens]

It may also be a defective memory module. If there is a memory module inserted in the CPU, try starting the CPU without the memory module (minimal HW configuration) after a memory reset.