I found this video on testing NPN and PNP resistors () which got me thinking, would it be possible to do the same basic test with a multimeter while the transistors are in circuit?
It just seems a fairly common occurrence for people to have issues with these boards from non illuminated LED's to accidental shorts while doing voltage checks. I just thought it might be useful to put together a short test procedure to verify if the transistors are functioning or not. Does that sound feasible?
Also if you ever have the chance to alter the board design you should consider adding a few dedicated test points, that should avoid accidental shorting of the transistors and also serve to verify they are soldered onto the board properly.