It's possible you might have a voltage/connection problem BUT even if you are using the original 44 lamps, BH chasers do move pretty fast so the lamps don't really have time to fully light up. If you have 47s there I would try switching to 44s. Also try an LED in one spot and see if it is a lot brighter than lamps, that could rule out an actual problem since they light up instantly. Also you can slow down the chaser lights by changing one resistor on the chaser board (noted in pinside someplace), or just switch to LEDs. That resistor might be out of tolerance on your board too.
Strangely enough, two days ago I finally slid my BH's inner backglass out for the first time since I bought the game in the 90s to clean both backglasses (can you tell I'm lazy?) and the lamps were all very dusty. You'd think they were frosted bulbs! So that can help too if you haven't done it.