The RCA socket is soldered to the input circult board, This can break in shipping if not protected properly. It is however, easily repairable by a skilled technician for not too much money.

Although I am interestd to find out those BT phone socket labled Network were every used?

561, HD621, DSP5000s(24/96), DSP33C, DSP33 surrounds, Pioneer DV575A CD/SACD/DVD-A, Panasonic DB170
(561 to be replaced with G68 shortly.)