I transferred the system to UTF-8 from WINDOWS-1251, it went well, everything works, only the search fell off.
There is an index.php (UTF-8) header.php (UTF-8) connects to it (it forms the header where the search form is located), it also connects search.js (UTF-8), which reads the request entered by the user and requests search.php (UTF-8), which is looking for the whole thing.
The problem is that after the transition, it stopped outputting data from the contact table, and from the tasks it puts data into the search.
I can not understand the reason.