Have spent a few hours over the past three days working on my daughter's 87 Norcold, not sure of the model number.
We are running on 120 AC. It has been getting warm and making gurgling type noises since we first plugged it in. It's been plugged and unplugged for several hours at a time.
Today I had time for more in depth diagnosis and cleaning. Pulled the roof vent and cleaned the screen which which was partially clogged. Definitely improved the airflow. After cleaning out the vent, and leveling the trailer last night, the sound in the back of the fridge is more consistent like mine. Just more of a steady hissing type sound with an occasional burp.
Pulled the cover off the stack. AC heating element is definitely doing it's job. Hitting almost 400* where it's connected to the boiler. Drawing a steady 2.75 amps. Primary tube at the top is about 160 at the highest point before going into the condenser. Coming out of the condenser around 80. Ambient temp was about 55 today. Recovery tank was about 80 degrees.
There still didn't seem to be any cooling happening tonight.
I'm not having much luck so far finding any info of what the temps should be. At this point I may pull the fridge tomorrow and flip it for the day and see if that helps. She just purchased the camper, we do not know how long it's been since it was last used. Fortunately everything else has worked fine and I got real lucky fixing the black tank pipe connection.