Woody wrote:


Have you tried adjusting the bias to see if you makes any difference?

** It won't.


If you Google 'schematic RA970BX' you will get copious information
including the service manual which includes how to set the bias. I
suspect it will correct it.


** Not a chance - DC offset is an input problem, usually due to a combination of input transistor bias current and diff pair device matching.


You should ideally be aiming for 10mV or less offset.


** Not necessary at all - rare exceptions already noted.


.... Phil