Detecting defective electrolytic capacitors when they are still in the circuit is a difficult and complicated job. The use of an ESR meter to it will allow the technicians to identify the damage is easily and quickly. This device is very important to measure the characteristics of electrolytic capacitors in the form of equivalent series resistance (ESR).
If you want to have an ESR meter can be through purchase in the form of a kit or DIY or buy a device ready to use it online like at Amazon. If you want a simple one, you can make it follow the instructions of the device schematic from tech info on the internet.