It's an MJD31, which is equivalent to a TIP31 (a popular 3A 40V NPN transistor).
To see if it is causing the short you could just unsolder the Emitter lead. Inductor L3 looks like its insulation has broken down, and will also need to be replaced or rewound.
Best Answer
Looks like an IC inserter. Inserts 14 or 16 pin DIPs.