I have NEVER seen a mute button on the TV, only the remote.
Try the procedure with the OEM remote if you have it or a
universal that emulates the needed buttons. In the olden
days instructions were often written in "Janglish" & not make
sense or be just plain wrong to us.
It is a kind of Sony clone on the outside. The CRT may even
be a Wega jug but a grade B or C overrun. This set is also a
perfect example of why the TV biz ended. Nobody to call at the
factory even for minor tech questions & the sellers just scrapped
them NOT fixed them under warranty.
73 Zeno
LFOD ! GBA !