The bad news is: it may need a charge of freon
The good news is: Freon for this guy is easily and readily availible to the public(R134a) Get a tap and shoot some in. Remember this: 1/3rd of a 12 ounce can is all you need. Overshooting the ice box will cause choke down of the compressor. To be in the zone the low side pressure should be hovering around 5 psi.