Faulty PCB classic symptoms?

[Hkphooey]

Hi guys
What are the classic fault symptoms of pcb issues on baxi/potterton?
Though I can get some heating and hot water out of mine, it's still going into reset mode when I switch it in certain circumstances.
I did have pcb fault lights ta while back but now just the one red light, but boiler kicks back in when reset.

 

[Knappers]

PCB faults are usually where you end up when all other possibilities have been eliminated.

 

[Ben-gee]

Phone Baxi, with any luck you’ll get “Rosemary, the telephone operator”!!!

 

[Hkphooey]

PCB faults are usually where you end up when all other possibilities have been eliminated.

Yes that where I am... And looking to try a replacement.
Looks a simple job, and have purchased a refurb, though my original has a extra light for condensate pump issue the new one doesn't, they are saying it's the right one.