Potterton 60 PrimaF-Electronic control. Open vented conventi

Would be grateful for any help.
Intermittent fault, not all the time. Have a problem with my boiler, in that when calling for heat, fan works ok but it (fan) does not run without cycling on and off.

The instruction manual states that it is the electronic control that needs replacing.

Can anyone tell me if the electronic control is solid state and therefore un-repairable. Once boiler has fired up no other problems, but some times takes three goes at fan cycling on and off before firing up again. I must admit to thinking it must be the air pressure switch with these symptoms. I have blown through the tubes and satisfied myself they are clear and APS appears to be working. Would be grateful if anyone can give me some reassurance to buy the electronic control. Thanks.

That's the classic failure - mode of those electronic control units. One day it'll just sit there forever going on - off - on - off and not lighting properly.

Thanks ChrisR, will order one ASAP, although it's holding out for the moment, touch wood, I'll bet it stops on Christmas Day knowing my luck.
I'm still of the old school of thought, thinking I can repair something, one day I will just accept I should just replace it.
Thanks again