You discrepancy code table in config.php and database.
Just for verification:
Open config.php, at the end be serch a line:
On the working forum do not change it (!!!)
Code:
// $ Config ['Mysqli'] ['charset'] = 'utf8';
If it is so then:
Forum is not set correctly.
You need to convert the database
Download it in the encoding, in which there is a "comparison"
Afterwards.
On the local computer to fix the encoding
Then pour it back into the correct coding
Open phpMyAdmin, find the table Post
Пролистай ее, несколько страниц
Ты ее должен читать, и на должна отображаться в твоем языке