© 2007 by General Electric Company. All rights reserved.
M1110150 006
3
Chapter 2: Functional Description
AC power is fused and filtered by the EMI Filter before it is converted to 12V DC by the Power Supply and
delivered to the Control PCB. The Control PCB consists of three identical buck regulator circuits that are
configured as constant voltage/constant current sources with the ability to adjust the constant current source
output to the LED’s. The Control PCB drives three pairs of LED’s on the LED PCB and the 12V fan. The LED PCB is
only enabled when power is supplied, the Standby Switch is “On”, the Pad Shutter Switch is closed and the
solid-state thermostat on the LED PCB is not tripped. When the solid-state thermostat on the LED PCB is
tripped, the fan still gets 12V to help cool the box. The Control PCB also delivers 12V to the Standby Switch
lamp. When the LED current sensor on the Control PCB detects that at least one pair of LED’s is not working
properly, the LED module failure indicator on the Front PCB blinks. When the thermostat on the LED PCB is
tripped, the unit overheated indicator on the Front PCB lights. Whenever power to the LED PCB is “enabled”, the
hour meter gets the signal to count hours. See the schematic on the following page for more detail.
EMI Filter
2 Fuses
AC 110 - 240V
Power Supply
Output DC
12V 5A
Chassis
Ground
Control PCB
Stand By
Switch
12V Lamp
Pad
Shutter
Switch
Front PCB
Hour Meter
LED Indicators
6 LED PCB
T-Stat
Fan 12V
J2
3 LED
Current
Drivers
750mA 1.5A
Fan
12v
LED Current
Sencer
Over Temp
Sencer
J2
J1
J1
J5
J4
J3
Enable
J2
J1
J1