how to repair a burnt twin tuner?

Hi all. I have a sony DMR-XS350. When connected its saying ASTRA 2 Satellite Not Found. I have been led to believe one of the satellite receivers on the rear panel may have burnt out, if this is the case, what visible signs should I see to confirm this and is this as simple to repair as 'just' replacing the errant part? Thanks for any help or suggestions.