Gilderfluke&Co Back to the Future - Manual (Page 5)

9) Speedometer Cluster Breakout: This small printed circuit board breaks out the six position RJ-12
to discrete wires for connection to the speedometer and tachometer motors.
The speedometer and tachometer motors are 0-10 volt input Beede 9303430991. They
rotate approximately 270 degrees, based on the voltage input with no additional support cir-
cuitry.
The last signal to this breakout is used for dimming the speedometer cluster backlighting.
A 2N3906 bipolar transistor inverts this signal and feeds it to the input of a IRFZ44N ‘N’ chan-
nel FET power transistor for controlling the incandescent light bulbs used for the speedometer
cluster backlighting. With heat sinking, this FET is rated at over 40 amps continuous capacity.
Fifteen VDC power for the back lights must be run from the power supply to this card. The po-
larity of each connection is clearly marked on this card.
G ILDERFLUKE & C O . • 205 S OUTH F LOWER S TREET • B URBANK , C ALIFORNIA 91502 • 818/840-9484 • 800/776-5972 • FAX 818/840-9485
E AST C OAST /F LORIDA O FFICE • 7041 G RAND N ATIONAL D RIVE • S UITE 128d • O RLANDO , F L 32819 • 407/354-5954 • FAX 407/354-5955
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