No light On s7 300

hi all 

So pulled a old S7-300 out of a scrap machine at work for education purposes.

plugged in my 24vdc supply and i am not getting anything, no lights no nothing.

My PC adaptor has power light MPI light and USB light and these lights come off when i unplug from the CPU

when looking for accessible nodes i also get the message Online; No active partner can be found  

is it a case of the Unit is Fried?

thanks

Mike

Fozzy

hi all 

So pulled a old S7-300 out of a scrap machine at work for education purposes.

plugged in my 24vdc supply and i am not getting anything, no lights no nothing.

My PC adaptor has power light MPI light and USB light and these lights come off when i unplug from the CPU

when looking for accessible nodes i also get the message Online; No active partner can be found  

is it a case of the Unit is Fried?

thanks

Mike

 Hello Mike,

  Even 5V led on the CPU? 

no lights what so ever

SF DC5V FRCE  RUN or Stop

thanks

mike

Fozzy

no lights what so ever

SF DC5V FRCE  RUN or Stop

thanks

mike

 Mmmmh you are right, I think is fried 

Well thats done it then lol

thanks for your help anyway

mike

Hello,

did you try another power supply? This can look very simple but who know...

Yeah that was one of the 1st things i did

thanks

mike

Fozzy

My PC adaptor has power light MPI light lights come off when i unplug from the CPU

 Hello Duris,

I thought that because I had read ....

Hello Ste,

can you pls explain more what you mean my friend?

Hello all,

I had the same situation in working plant. Before shutdown everything working ok. After 3-4 days, on power on CPU wont start. No reason found why this happened. Replacing CPU started the plant. what can be the reason behind this?

After that I opened plc to check and internal components found damaged. Now supply was from UPS but assuming problem with supply, shouldn't be there some internal protection to cause minimum damage, like fuse?