Just everything was doing great. I just filled up a cylinder. shut the air compressor down Hooked up another cylinder, carried the full cylinder out to my truck, got a glass of water went back into the shop big hum coming from the compressor motor stalled I guess I don't know whether it's the electric motor which I don't think so I think the compressor locked up or something I wasn't there to hear it. I'll have to call pyramid Monday and see about sending it back. everything was pretty well perfect until this happened. Good thing i keep 10 or mire cyls @ all times! Any one else have similar problem?