Ariston Microgenus 24mffii A01 fault. PCB?

[MK Heating]

Hi guys. I've got an Ariston Microgenus mffi 24 non condensing that keeps displaying the A01 fault. Press 're set and it resets fine, fires up ok but the ignition keeps clicking, then after a while it will knock off again. It's like the boiler isn't detecting a flame as in the ignition sequence isn't stopping but it stays lit for quite a while so it must know the flame is there somehow. Checked the lead and the electrode and there seem fine. Boiler doesn't modulate either, it's either on full or off. Am insight to think a PCB fault. I'll put an electrode in while I'm at it. PCB is £265 locally though so is rather get it right. Have quoted them for a new boiler which they're yet to decide on. I'd like advice on this if possible invade they won't change it . Thanks guys!

 

[townfanjon]

If its not rectifying it will stop in seconds . The non modulation does nt sound good , but TBH dont know the boiler