Appa 63N multimeter, display turns entirely on
 

Hi

I got this as broken, they said I just have to find the right place to
the rotating selector, but after cleaning it and rotating it for some
time, I see that when I turn it on, the display just comes on,
everyinh (8888), only for uA I get the uA sign, the only thing I can
control in the display

Have anyone seen this before? Any suggestions?

WBR
Sonnich