Hello @iradu ,
Welcome to the Poly Community.
The community search will find many posts about this over the years. As this is the official Poly community we cannot recommend any hobbyist approach to try to repair the units.
As we have no idea how old all of these units are the default answer is there is nothing you can do.
If official support is required please check how to phone or open a case here
The title Poly Employee & Community Manager is a community setting and does not
reflect my role. I am just a simple volunteer in the community like everybody else. All posts and words are my own & do not represent the views of Employer. ----------------
Notice: This community forum is not an official Poly support resource, thus responses from Poly employees, partners, and customers alike are best-effort in attempts to share learned knowledge.
Please also ensure you always check the VoIP , Video Endpoint , Microsoft Voice , PSTN or other FAQ's in the different sections