Try to give us more info on your symptoms. Which lights, EM or SS etc. And check the fuse holders. Jump both side of the fuse with an alligator clip see if they come on.

Whoops, i had Sinbad on my mind. Just worked on one today. Which lights.

I think you are on the right track with the transistors, did you look up to make sure your new transistor has the same lug configuration E,B,C? Take out the driver board inspect it check the transistors with a multi meter see: http://www.pinrepair.com/sys1/index.htm#lamp
This should help you solve the problem.

E = Emitter B = Base C = Collector

Different configurations of these pins make up diffrent types of transistors. Getting them properly installed is highly important.

Also check the lamp matrix, see which transistors in the matrix drive the lamps that are not functioning, then test and replace these as needed.

EBC = emitter, base, collector .. sometimes replacement parts will have different legs.
I recommend going to www.nteinc.com for compatibility issues.
They used to be ECG but NTE bought them out. We still have all the old paperback cross reference books at work. (sorry about the late website edit)