MD-82
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Flight Crew Returned To Departure Airport; General Declared Emergency
Aircraft
Ten minutes after take off we received 4 chimes from a Flight Attendant advising us that they had detected some smoke and fumes around row 8.  She said she will investigate it more and call us back.  In the meantime; I elected to run the 'Smoke/fire/fumes' checklist.  Within about a minute the Flight Attendant called us back and informed us that in fact there was smoke and fumes coming from an overhead bin; and it smelled of melted plastic. At that point she was told to keep us updated and that we would declare an emergency and return to [departure airport].  We declared an emergency with ATC and requested vectors back.  Requested ARFF crew and the frequency for them. Advised Tower we would stop on the runway.  After we stopped; the First Officer coordinated with the ARFF crew while I made a PA to the passengers and flight attendants.  I then opened the cockpit door to get a better visualization of the cabin situation.  I asked the flight attendants if it was under control and could we just taxi back to the gate promptly.  Their response was; 'Yes; it's okay; taxi back to the gate.'  I told them to brief the passengers that when we get back to the gate that they were to deplane promptly without their luggage; and that rescue crews would be boarding after that.  To my knowledge; no injuries were sustained.  Maintenance determined it was a light ballast that overheated.
[Narrative 2 had no additional information.]
MD-82 flight crew reported a Flight Attendant called with smoke in the cabin. They declared an emergency and returned to departure airport where a defective light ballast was determined to be the probable cause.