I have fixed a ton of primas with that fault and sorry to say its always the board, if you can drop it down you will see one of the relays dropping back.
j
The is a number of things that could cause the burn out as DP says relay contacts could be an issue with one of the diodes or the bridge could have shorted. If its on the fan and pump circuit then just check they are free and check them for resistance then pop in a new board and fingers crossed...
I would take the time to check the appliance over carefully prior to disconnecting and removing, and so a quick run over with the FGA first would be a good idea as it can pick up issues such as vitiation caused by perforation of the inner flue duct, something that you may not see from a visual...