RV Repair: Flame cuts out on Norcold fridge, happy camping, board tester

Question
I have a Model 6162 Norcold fridge. On electric, it works fine. On gas, the flame cuts out as if the burner didn't light but the flame actually looks normal. I don't see any sensor to determine if the flame is normal or not-no thermocouple. How does it determine if the flame is normal? The unit is about 10-11 years old (1994 Chateau trailer bought new). Never repaired except that I clean the burner occasionally when rust falls down on it.Gas pressure is normal-11" water.
Thanks.

Answer
Bill,
    The same wire that provides the spark for ignition through the electrode is also what tells the circuit board that it is lit and allows the gas valve to stay open.  It does this by completing a circuit to ground using the flame as the conductor creating the correct amount of resistance.  If the burner tube is clean and gas pressure correct there are only a few things that could be causing the problem.  Low DC voltage is the first one to check.  It will need a minimum of 10.5 volts to work.  If that's okay the next thing to check is the electrode and wire.  The electrode needs to be 3/16" from the burner and in the flame.  You need to make sure that neither has a short to ground, or an internal break.  The spark can jump a break in the wire for ignition but can't send signal back to the board.  The last thing is the circuit board it self.  You can remove it and call around until you find a shop that has a fenwal board tester and they can test it to make sure its bad before you shell out $100+ dollars for a new one.  I hope this helps, good luck and happy camping.

Darren