First try cleaning the electrode. Be careful not to put too much pressure on it as the porcelin can break and if so you will need a new one. While you are in the burner area be sure it is clean of any debris. THe electrode mus be in the flame and about 3/16" gap between it and the burner. Otherwise you may need a board. Some of the parts places with shops have a tester to verify a bad board. Good luck and let us know how you come out.
Mike, RVIA & RVSA Certified Master RV Technician
Amy, Dr. Assistant - Roxie & Mei Ling, four legs each
2000 Gulf Stream Scenic Cruiser 450 hp & 1330# torque
06 Saturn Vue, 06 Chevy Z71 4x4 & 2014 Corvette Z51 M7