Forcing them in damage the traces on the lamp board? I would tweak the contacts a little to relieve the tension on the contacts before twisting them in. Also put the game in "burn in" test mode to light the feature lamps so you can narrow down any flaky sockets. Any lamp that won't light is most likely the result of a blown scr or transistor. There are 2 lamp driver boards on Spy Hunter, the lower left board the small one in the lower middle which is the auxiliary lamp driver. You will need your manual to determine which scr controls a specific lamp.

Oh, and adding LED's to these early solid state games usually results in lamps strobing (blinking very rapidly). You will need a special lamp driver from Alltek to eliminate the strobing. Can be found for $100. LED's do not draw enough current to let the scr's function properly. The Alltek board is designed to use with LED's by adding a jumper wire to the feature lamp circuit.