That is exactly the same issue I was having with my board.

http://aussiepinball.com/index.php?topic=14122.0

Pascal believes it's either a diode or transistor on the board that is the problem.  You should have got a spare one of each of those with the board.

Check the driver transistor Q1 on the board (just above A3J2).  Also check the diode just below Q1.

I still haven't fixed mine.  I tried desoldering the diode to start with and simply cannot get it out.  I think the fact I have a $15-20 dick smith soldering iron might be part of the problem.    I don't think it's getting hot enough.

So Im still waiting for a mate to come round with his Hollywood version and will try again then, since I don't want to screw up a nice new board.   I might have to finally upgrade to a decent one myself.

Why wait, they are cheap enough:

http://www.ebay.com.au/itm/331271359481

Get yourself some spare tips some small and some larger ones too at the same time.