Hello and sorry you're having problems.
The issue you're having, in most cases, is due to the laser lens being either contaminated (dirty), or faulty (scratched or mis-aligned).
Follow the steps below to determine and attempt to cure the issue.
First, unplug the Bose system cables from the changer to the main unit and disconnect the changer from power.
Wait a minute the reconnect the changer to the main unit and attempt to play a disc.
If the issue persists, then you can try several methods of cleaning the laser lens to see if it helps clear up the problem. The first is to purchase a CD/DVD laser lens cleaner disc, and run it through the system several times.
The next would be to use a can of compressed air and liberally spray into the disc slots to remove any dist or debris from the changer.
If these user fixes don't correct the issue, then in this case you would need to contact Bose Service, as they are the only ones that repair their systems:
For assistance with your product, please call us toll-free at 1-***-***-****. For help with our aviation headsets, call 1-***-***-****.
For the best possible service, please have your product nearby when you call. Hours of operation: Monday – Friday: 8:30 AM – 8 PM ET
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