Paul01

The machine was in a factory and running. The panel was switched off and has been in storage for a few years until we bought it. (have the previous owner helping me with the install) When  i powered it up i found that the cpu didnt power up so curious why it blew the fuse. There is no signs of any damage on the board. i might get a electronics repair company here in ireland to have a look at it. If the cpu is powered up without the sd card will indicatorlights still light.

The complete panel was just disconnected from the mains but no internal wiring was touched and there is 24v goin to the cpu and the polarity is correct. I took the cpu apart and found a solid state fuse had blown. Goin to try replace it tomorrow. The fuse is a omf 125 4A. Can this main board b got without having to replace the complete cpu if this fails. If you power up the cpu without the sd card in the slot will u get any indicator lights. 

Thanks bryll. The switch is in the run mode. The sd card is in the slot and there is no leds lit 

Hi all looking for some advice on a siemens s7 300. Im not familiar with the siemens plcs i have just powered up a machine which was in storage for the last five years. The screen starts up and works but the plc when powered up does not bring on any indicator lights at all and the screen brings up a coms error. Some of the input lights are lit as expected. Am i right in saying that the plc is dead. And is the program stored on the sd card which is inthe slot in the front. thanks

Hi all looking for some advice on a siemens s7 300. Im not familiar with the siemens plcs i have just powered up a machine which was in storage for the last five years. The screen starts up and works but the plc when powered up does not bring on any indicator lights at all and the screen brings up a coms error. Some of the input lights are lit as expected. Am i right in saying that the plc is dead. And is the program stored on the sd card which is inthe slot in the front. thanks