1602 lcd problem

Hello ,
I have a big problem with my arduino project. I made an heart rate monitor , usign an arduino nano, tcrt1000 sensor , mcp6004 , and 1602 display . All good all fine , the code is ok , i tested all project on a prototype , but when i made the pcb , and i made the connexion to the power source , all i can receive from the lcd is some random numbers . ( the corect first message is " heart rate monitor" , not some random numbers )
O can t find anything wrong . Maybe some of you can help me with an ideea or something else.
Thanks !

First read the instructions!