Pinball lights not working

[Dio 70]

I have noticed that some bulbs on the playfield and coin door are not lighting up.  These lights worked about three weeks ago.  I tried changing the bulbs and that did not work.

Any ideas what would cause the lights not to work?  I have a Taxi machine.  I did turn on the bell through the game adjustment menu.  It's pretty cool to hear a bell ring during game play, but I am not sure if that caused certain lights to go dark.

Any help is appreciated.  This is my first pinball so I am a novice at pinball repair.

[John's Arcade]

I have noticed that some bulbs on the playfield and coin door are not lighting up.  These lights worked about three weeks ago.  I tried changing the bulbs and that did not work.

Any ideas what would cause the lights not to work?  I have a Taxi machine.  I did turn on the bell through the game adjustment menu.  It's pretty cool to hear a bell ring during game play, but I am not sure if that caused certain lights to go dark.

Any help is appreciated.  This is my first pinball so I am a novice at pinball repair.

It could be a transistor. It's possible they are all on the same one. Do you have a manual? In the manual it will show which matrix of lights are on what transistor.

Check this out:

http://pinwiki.com/wiki/index.php?title=Williams_System_9_-_11#Lamp_problems

[Crazybanana]

Check the connectors to the GI Lamps in the back box , Replace any that appear burnt. Also you should reflow the solder on the GI connectors Solenoid Driver PCB and any other points that appear to have cold solder
Best of Luck