Need help troubleshooting air conditioning

[davislau]

I doubt I overcharged the system because I only squeezed the trigger for a split second to get a pressure reading. Then, when I held the trigger down, the pressure either remained constant or dropped slightly. I think the pressure in the can was not high enough to overcome the pressure built up on the low side of the system.

I finally paid a mechanic $40 to diagnose and they said the compressor was bad.