I finally got all the lamps working but now I am having a strange problem with my "5 x" lamp.
During attract mode, and in lamp test mode, all lamps display at the appropriate times but as soon as I start a game, the "5 x" lamp starts flashing. 
I thought this must be a short somewhere, but the fact that it works fine in attract/test mode makes me wonder.

Anyone come across this problem before? 

Edit: Nevermind.  I just had a look on visual pinball and it looks like the "5x" is meant to flash.