RB751G-2HnD wireless dissapearing

Hi,

I have RB751G-2HnD for few years and until few months it worked OK. Then, suddenly, wireless interface dissapear from interface list. After reboot, sometimes wireless appear, sometimes not so I need to do another reboot (than it appears). It works for maybe few tens of minutes (with higher wireless load this time shortens, so if load is higher it can work for only tens of seconds) and than dissapears again.

It is not related to RouterOS version ( I tried lot of different versions). Does someone knows what could be a problem and is it reparaible?

Thanks.