Hello, I have recently purchased a used Phantom 1 from a realtor friend that upgraded. I've read as much as I can find and watched videos but can't get it operational. I've updated the firmware, calibrated, everything I can think of to get it to work. When I attempt to turn the motors on, three of them flutter and chirp. The fourth seems dead. At no time will any of them spin up to pre-flight RPMs. Any ideas would be appreciated. Thanks in advance!