ADAT popping help

[Signal 9 Studio]

My RD-8's are occasionaly making a popping sound on individual tracks. It is sending it into the red. Every now and then POP! I have checked and it is not registering during tracking (so its happening from the board to the adat or AT the Adat) only when I play it back. Has anyone else had this problem with their adats. They probably do need cleaned but I dont know how or what with. I have to get this solved...I cant edit out a hundred pops and cracks.

 

[Track Rat]

Sounds almost like a clock issue. How do you have the clock in the ADAT set? Any other digital devices (like a mixer) envolved?

 

[Signal 9 Studio]

I have three of the adats hooked together. The master is set to Internal. The other two are set to LTC(SMPTE in connector) I do adat connect which is a clock source but when I record I leave my computer off. Could it still be sending some sort of signal? I thought the comp had to be on for the lightpipe to send a signal?

 

[Blue Bear Sound]

Why would your other 2 units not be connected via the ADAT sync cables?