Dell Latitude E6420 XFR (Early 2011) - Manual (Page 16)

Dell ™ Latitude™ E6420 XFR Service Manual
Page 16
5. Disconnect the antenna connection from the RF Passthru board to the WWAN card if present
6. Disconnect the antenna connection from the RF Passthru board to the WLAN card if present
7. Remove the M2 x 3-mm screw that secures the RF Passthru board to the chassis.