Repairing Endress & Hauser Cerabar PMC731 Pressure transmitter with Error 110

We have 15 Endress & Hauser Cerabar PMC731 Pressure transmitters with error number 110 and we hope someone can guide us to fix them.
According to the guide, the error is in the electronic board and we tested this with a healthy board and it was correct.
Does anyone have experience repairing the electronic boards of these transmitters?
What is the main reason for the failure of these boards?
Many thanks in advance for your help.
I'll speculate that if the failure is the electronics card with the 4-20mA/HART, Profibus or Foundation Fieldbus communications, then I'd guess that near lightning strikes take out the electronics due to long cable runs' ability to pickup induced voltage from the lightning. But it's speculation.