RV Repair: Nomad camper 120v elec problem, fuse panel, circuit breakers

Question
QUESTION: I have had an intermittent problem with 120v system in a 2003  29'  Nomad Scout.   12v system ok. 120V now out completely.  Have tried replacing GF receptical in bathroom and have opened panel to chk for loose wire on breakers.  How do I test breakers?Main is 30-15 other 2 are 15-20. Have power going into camper.

ANSWER: You have power going into camper.  I assume you have tested the power at the fuse panel.  If not, you take the breaker panel cover off, the door is attached to that.  then you get a good meter or voltage tester and check for voltage coming into the main breaker.  Then you test after the main breaker.  then you test at the wire going into the breaker you have a problem with.  Make sure the breaker is on and not tripped.  turn it off and back on to reset it.  if power is available in all these places, you have to suspect the places the power is sent to.  Outlets, switches, etc.  check for power at all these places by removing the switch, outlet, etc from the box it is in and test the wires at the connections.  

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QUESTION: Ok that didn't solve problem.  Have found problem in campground power box on 30A feed.  It finally went completely out, but still haven't been able to get the 120V power in the camper working.  Have replaced 2  15/20 circuit breakers and the GFI plug in bathroom.  Have power coming in and the 12V system workes but is not recharging battery now so put charger on it because of refrig and frunace power needs.  Did this power wiring problem in the outside campground box that was intermittent and then finally out cause a problem in my 120/12 converter?  That part is kinda expensive to replace.  Is there some way I can check it out without replacing.  My unit has the converter part in section below the circuit breakers and that lower section can be replaced by itself.  Thanks.

Answer
check the plug end of your cord.  You may have burned out the actual plug.  They sell these plugs at Home Depot.  My camper is a 2010, i bought it used and this plug has been serviced before I got it.  Slightly expose the wires on your wire behind the plug and check for 120 there.  If you have it there, go to the other end of the cord where it connects inside the camper and check there for 120V.

good luck.  sorry so long with response.  I was camping the last two weeks and forgot to turn off the all experts questions.