I looked all over to find a new CD changer for my 94 Q45 and kept getting the bullsh-- run around. I finally went to a Nissan dealer and they were able to order me a refurbed Sony just like the one in the car for $350.00 (I had to turn in my not working one for a core). Put the refurbed one in and it is running like a champ.
There are a few places online that can repair your Sony model (do a google search for cd changer repair). The place I sent my not working unit to specializes in repair of these and other units. They could not repair mine because it was broken beyond repair. They sent it back to me no charge. You might try that before spending the big money on a refurbed unit.(the cool thing about repairing the one you have, or trading it for a refurbed sony is that it fits right in with no hassle and no adapters etc.)
I can't remember which repair shop I sent mine to (it has been about 2 years)It was one of these two links
http://www.willmanselectronics.com/infiniti.htm
or
http://www.johnson-electronic....x.htm
good luck