dti 6300 wont update

Hi there,

anybody know why my box wont update to the lastest version software (7.04 i think)
i have replaced the power supply caps as it would not boot and the caps were dammaged when i took a closer look.

now when i try to rescan it says channel 16 - QVC signal is too low, but when i watch that channel it is fine with a signal of 6.
my other box updated fine.
is the tuner on the way out?

cheers