I have a 93 240sx fastback and for some reason the power antenna mast won't install. I have already looked at 240sx.org and even have the factory service manual and none of them help. I put mast in w/ gears towards motor, turn on radio, and mast goes down but it stops with about 6 inches left. I turn radio on and off quickly and the 6 inches still remain. Anybody got any ideas what i'm doing wrong? BTW mast is genuine OEM from dealer so its not that.