Inverter compressors can run really smoothly and quietly these days -- so quietly that it can be hard to tell if they're running at all, let alone if they're running properly. So if our ears and hands can't tell us what's up, what do we do to test these compressors?

Time to apply our brains and our meters: we're going to use the schematic and some simple electrical measurements with our ammeter and our multimeter to know if the compressor is running. 

Step 1 is to use the schematic to identify the pins on the main control which connect to the inverter. That'll be the power supply and PWM speed signal going to the inverter.

Step 2 is to use our amp clamp to see if there are any amps moving through the compressor's circuit. Remember: these ain't yo mamma's old split-phase compressors, so the amps might be way lower than you would think!

Step 3 is to check the frequency of the PWM signal line. Hisense doesn't give a Hz spec for this just that the frequency should be stable, which we can see on our DMM.

Is it possible to have volts going to the inverter and a stable PWM frequency but the compressor still doesn't run? Yep! Simple test is to check your amps. If no amps to the inverter, that means the compressor ain't doin' nuttin'. Once again, amps is our hero! 

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