Inverter low output

My inverter output has dropped to 195 volts from 212 volts a couple of weeks ago. 3000watt pure sine rated at 200-240 volts.I checked inside and there was a switch whose highest position was 220volts The weather has changed from hot to cool and that is the only change I can think of.--3000 watt DC Master brand pure sine 12 volt inverter.Is my inverter dying YES/NO?
Comments
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
Try measuring AC voltage under load, it may be different to no load, ambient temperatures may change the value of electronic components which may in turn change the voltage, hense the tollerance in the specs, looking at the specs of my cheap inverter, it's +/- 10% voltage regulation, so at 220 V could be 190V or 242V, better quality will usually have less spread and I'm not talking Vegemite.
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
Look for signs of heating or overheating (dirty or poor electrical connections).
Bill
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter