"What type of problems are you having with the unit?"
"There is a sort of drift between channels."
"Drift? I'm not sure I know what you're talking about."
"The stereo image isn't stable."
"Stereo image? Again, you'll need to explain that a little better."
"The panning isn't fixed. One channel will suddenly get louder and the other softer."
"That is not a known issue with this unit. Did you [check all the other things that might be contributing to a wavering audio signal]?"
"Yes. It's only the analog outs that are a problem. I can ADAT the signal into another sound card and get perfect stereo from that card's analog outs. According to the specs there is some sort of 'servo-controlling' of the pan. Could that be out of whack?"
"No, no. That would be a hardware problem."
"I think we're talking about a hardware problem."
"OK, what about this? Is there corrosion around the output jacks?"
"Yes, I think there is."
"OK, here's your job number. Send the unit back to us for inspection, and write the number on the outside of the box."