HakenTT's idea is slick, but it doesn't address your problem as your initial splicing method powered both up successfully. What kind of preout are you using on the old deck (Front, rear, non-fader)? Does the new deck have a switch to activate the aux input? I know some Eclipse and Alpines I have used in the past did. You can try the output from an MP3 or Discman to verify that the the input is working. Check that your fader settings are correct on the old deck to ensure you do have a line level signal being feed into the new one. I live downtown near the Kennedy and Addison if you need some help.