There are many others that can provide you with better insights to your problem than I, however I will give it a go.
The problem could be either at the coax output of the CDP or Coax input of the DAC. It can always be a bad cable however since you had an intermittent problem with the IC this might not be the case. Since the problem seems to be at both inputs of the DAC lets start with the CDP. Can you borrow another player, even an inexpensive DVD player, to run into your DAC as a way to remove your CDP as the problem?
You should also try another cable to best remove that as a possibility.
Which Cambridge DAC do you have? Was it purchased new or used?
Take it one step at a time.
The problem could be either at the coax output of the CDP or Coax input of the DAC. It can always be a bad cable however since you had an intermittent problem with the IC this might not be the case. Since the problem seems to be at both inputs of the DAC lets start with the CDP. Can you borrow another player, even an inexpensive DVD player, to run into your DAC as a way to remove your CDP as the problem?
You should also try another cable to best remove that as a possibility.
Which Cambridge DAC do you have? Was it purchased new or used?
Take it one step at a time.