I got one of these years ago as a birthday present but rarely used it. I was looking to have a second temp controlled unit to do my fermenting and lagering while the keezer holds my kegs.
I stumbled onto Fall-Lines thread
about converting this unit to a fermenter and I decided to give it a try. The difference between his conversion and this one is that I use a 6.5 gallon carboy and installed an on/off switch in control box to kill the compressor.
The new switch allows me to still use the light and built in temp gauge at room temp without using the Johnson controller. Its not really necessary but, I had a spare switch lying around.
Modifying the box for the carboy was straight forward. I removed the shelves and cut a plywood base. The inside light was moved to the right as far as possible to accommodate the blow off tube. A regular 1.25 inch blow off tube would not fit without bending so I used a simple elbow from Home Depot to angle the tube and not restrict the flow.
I modified the wiring slightly different than Fall-Lines since I had the switch on hand. During normal ops, there is constant power being supplied to the motor. When the thermostat reaches the desired temperature, it interrupts the motors neutral and shuts it off. Instead of just jumping the neutral from the plug wire to the motor like the previous thread, I installed a switch to give me a way to turn the compressor of and on while still using the light and temp display.
With everything installed the fridge cooled down to 25 degrees in about 20 minutes. All in all it was a fun project and will allow me to ferment while serving.