Question edited for clarity.
Question moved to Cobra.
From the manual. Phone and ask them.
If this product should require factory service, please call Cobra first at 773-889-3087 BEFORE sending the product. This will ensure the fastest turnaround time on any repair.
If Cobra asks that the product be sent to its factory, the following must be furnished to have the product serviced and returned:
1. Send the complete unit, including power cord. (It is not necessary to include the mounting bracket.)
2. For warranty repair, enclose some form of proof-of-purchase,
such as a photocopy or carbon copy of a sales receipt. If you
send the original receipt, it cannot be returned.
3. Enclose a typed or clearly written description of the problem
you are having with your unit, plus the name and address where
you want the unit returned.
4. Pack the unit securely to prevent damage during transit. If possible, use the original packing materials.
5. Ship prepaid and insured using a traceable carrier such as United Parcel Service (UPS), Federal Express or Insured Priority mail with delivery confirmation. Ship to:
Cobra Factory Service, Cobra Electronics
Corporation, 6500 West Cortland Street, Chicago, IL 60707 U.S.A.
6. Please allow three to four weeks before contacting us about the status of your service. Call 773-889-3087 for assistance. If your unit is under warranty, it will either be repaired or replaced upon receipt, depending on the model. If your unit is out of warranty, you will receive a letter informing you of the repair or replacement charge.
https://www.google.com/search?q=cobra+xrs+888+radar+detector+repairs
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