Richard Robinson bought a Sony Betamax three years ago. He paid about $1,100 dollars for the machine. Today, three years later, it is worth at least $40. A likeable fellow, Richard feels betrayed by the Sony Corporation, who have outmoded his one-hour record-playback Betamax with their new three-hour record-playback Betamax. The new Betamax will not replay cassettes recorded on his old Betamax. Video cassette recorder salesmen laugh in his face when he asks how much they'll give him on his old Betamax as a trdde-in against the cost of a new Betamax.