I came back fro 3 week vacation and the icemaker on a GE ZIS42NY bulit in non dispenser refrig is not working. I checked the water flow through filter and no obstruction. I played with the stop lever and there is normal movement with no obstruction. My question: Do I call a repairman to simply replace the icemaker or is this something I can buy and replace?? I am not a plumber and only so-so at repairs.