siemens plc s5-115u Not working

I have a S5 PLC-115controller with me in a machines. It is very old machine. While running it shown batterey low alarm .so that we changed the battery in side the power module. After that machine started to work, then after few weeks again the same alarm came, we did the same. Finally after the third time machine stopped working.

HMI is wroking( Turned on). I can see all other lights and indications ON except plc.

Somebody please help me to solve this problem.

Hello Aneesh;

Maybe you could start by checking the contents of OB 34 in your CPU:

https://support.industry.siemens.com/cs/ww/en/view/15227300

Hope this helps,

Daniel Chartier