Capacitor is charged and discharge so it has specific voltage output so to determine easily the condition of capacitor is charge its and measure its voltage using meter so that it display charged voltage value by discharging. It has also other method let’s understand in details.
Remove the start capacitor.
The easiest and most convenient way to discharge the capacitor is to connect the terminals to a 120 V (about 20 W) light terminal at the capacitor terminals. This will discharge the electricity that can be stored further.
Be very careful not to short-circuit the terminals by connecting each other until the capacitor has been discharged. If you do so, you can hurt or kill yourself. Take special care when downloading the capacitor before proceeding
Examine the capacitor for inflation or fluid.
The signs that the top of the capacitor expands slightly, as it will expand, is a sign that the capacitor might be dead. Also, check for any liquid that appears on the top of the condenser.
If you see any of these, it’s still a good idea to run the check with a voltmeter because it only takes a few seconds.
Use an analogue or digital volt meter.
Both work essentially in the same way and are both suited for work. Set the meter to 1k ohms to start the test.
Touch the two terminals with ohm measurement cables.
The basic test involves double-tapping the test leads and comparing the reaction. Touch the test leads on the terminals and then invert them.
The needle in your counter should swing to 0 ohms and return to infinity on an analog counter and should display the line open every time you invert to a digital counter. If yes, you have a live capacitor and your problems are somewhere else. If there is no difference the capacitor is dead.
Check the capacitance if the capacitor is alive.
If you have a multimeter, you can use the capacity setting to perform a quick check. If the number is relatively close to the number listed on the capacitor, is in good shape.
Briefly, to test the capacitor with a multimeter, set the meter to read in the range of high ohms, somewhere over 10k and 1m ohm. Touch the meter connectors at the appropriate capacitor wires, red to positive and black to negative. The counter must start from scratch and then slowly proceed to infinity.