Sony Micro CD HCD-FX250 Lost sound from one Speaker outlet?

Hi, My Micro CD DAB "Sony HCD-FX250" has lost output from one side (I swapped the speakers over to check and both speakers work OK) I would like advice about how to disassemble the stereo as I suspect either a dry joint or perhaps a short on the audio output for the offending side (It hums and you can faintly hear the audio) Any advice or access to engineers manuals basically any help or advice appreciated (Can't afford replacement)