have an older connex 3300 , (serial number 402871) with this board in it ept360022z, talk back is on at all times with or without echo. the talkback is really loud and would like to know how to disable it, quieten it, or put it on a variable. I already clipped TR39 (no change)so I put it back.Also R249 had one leg clipped and was standing up, so I replaced it( no change) so i unclipped it again . Please help