Light & Sound

Light & Sound is an electronic system used in several Town and Space themed sets. It was launched in 1985 and progressively rolled out to all Lego's markets over the next two years. It was the first appearance of the next-generation 9V electric system which would eventually supplant the older 4.5V and 12V standards across all themes.
Initially, the system consisted of a battery box which held a PP3 type battery. Power was conducted via metal contacts built into the brick studs - replacing the wires and pinned plugs of the older 4.5V/12V system. The light and sound elements consisted of a "light brick" (in either simplex or duplex form), and a "sound brick". 
The light bricks can carry different coloured globes (blue, green, yellow or red) which can be changed. Depending on the polarity the light brick is connected by swapping around its position, it can display either a continuously lit or flashing mode. 
The sound brick exists in two themed versions: Town Siren (black) and Space Siren (white). Each of them has two theme typical sounds and a loudless mode, which can be chosen by turning the knob on the top of the brick. Reversing the polarity of the sound brick (i.e. removing and replacing it a different position) has the same effect as turning the knob. 
== Sets with Light & Sound ==
Town
* 6450 Mobile Police Truck (1985)
* 6480 Hook and Ladder Truck (1985)
* 6482 Rescue Helicopter (1989)
* 6430 Night Patroller (1991)
* 6440 Jetport Fire Squad (1991)
* 6483 Coastal Patrol (1994)
* 6484 F1 Hauler (1995)
Space
* 6750 Sonic Robot (1986)
* 6780 XT Starship (1986)
* 6770 Lunar Transporter Patroller (1988)
* 6783 Sonar Transmitting Cruiser (1988)
* 6990 Monorail Transport System (1987)
* 6991 Monorail Transport Base (1994)
* 6979 Interstellar Starfighter (1997)
Service Packs
* 5033 Light and Sound 1 x 4 Lighting Brick and 4 Colour Globes (1987)
* 5034 Replacement Light & Sound 1x2 Lighting Brick with Coloured Globes (1987)
* 5035 Town Siren, 2x2 (1987)
* 5036 Space Siren, 2x2 (1987)
Image:5033-1.jpg | 5033 Light and Sound 1 x 4 Lighting Brick and 4 Colour Globes
Image:5034-1.jpg | 5034 Light and Sound 1 x 2 Lighting Brick and 4 Colour Globes
Image:5035-1.jpg | 5035 Town Siren
Image:5036-1.jpg | 5036 Space Siren
Category:Light & Sound
Category:Town
Category:Space
Category:9V
Category:Service Packs
Category:Themes introduced in 1985