[Yaesu] re distorted rx audio FT-1000D

[Fern]

    I've got a friend's FT-1000D here that has a problem with severe 
distortion with the receive audio on the main receiver only. It sounds like 
an oscillator shifting frequency. I've already set the carrier oscillators 
for both usb and lsb as they were both off. I was told that there was a 
problem with a voltage regulator that was prone to cause this receiver audio 
problem. I have search google for any fix but came empty with that.
    Another issue that I notice with that radio is that the led display is 
not as  bright as my own FT-1000D. If I engage the dimmer option, then one 
can hardly see the display.
     Any suggestions as to where to go with this would be greatly 
appreciated. Any FT-1000D expert out there that I could contact?
    73 from Fern   VE7GZ