Guide :Air Tools & Compressors : EC12 Portable Electric 2hp Air Compressor, Oil Lubricated
Hitachi EC12 Compressor- weird hum
5 year old compressor, light duty use, less than 200 hours.
Now unit builds pressure, gauge of right side building fast, the one on the left slowly. When it reaches a certain pressure say 120, the unit suddenly blows off a burst of air.
After the burst of air, a weird electrical humm is heard for about 10 seconds, which stops.