Working on older refrigeration equipment can be challenging. Depending on its prior maintenance and repairs, or lack of prior maintenance, repairing the system can be a little tricky. Patience is a must while working on these older systems, as simple mistakes or careless actions can lead to some major issues.
It is best to perform a thorough visual inspection of the system before beginning the troubleshooting process. During this initial inspection, look for obvious problems that could lead to a simple repair, such as dirty coils, simple electrical failures, or control adjustments, as these tend to be easier repairs on older systems. The less you touch the refrigerant side of the system, the better. Some electrical repairs can also be challenging, as these systems can have frayed or brittle wiring, making it difficult and/or unsafe to take some electrical measurements.