Cooper Bussmann 858 - Manual (Page 28)

DOCUMENT 1025
REV. H
Instruction Manual
AGS-LED
858 LED Series
Sizes 1, 2, 3, 4 and 5
19
WARNING:
IMPORTANT
Power Supply Board must be re-calibrated after replacement.
(See Section 10.11).
1. Turn off power to the sign by turning off the corresponding Constant Current Regulator (CCR)
power. (WARNING: Wait five minutes after sign power is turned off to service the sign. This
will allow any residual high voltage stored in Power Supply PCB components to bleed off.)
WARNING:
WARNING
Failure to turn off power to the sign and wait five minutes could result
in severe injury or death.
WARNING:
WARNING
Circuit Boards need to be handled with proper ESD precautions and
care, before and during the installation process explained below. The
circuit board assemblies have components which are Fragile and can
easily be damaged before and during installation. The Large Heat
Sinks should be supported, not allowing it to bend/move until the
circuit board is mounted in the Power Supply Box.
2. With your multimeter set to DC Volts, verify that the Power Supply Output Voltage is less than 30-
VDC at TP6 (Positive lead) and TP3 (Negative Lead) as indicated in Figure 22. If the Power Supply
Output Voltage is greater than 30-VDC, then you must wait until the Power Supply Output Voltage
drops below 30-VDC before you proceed with the next step.
3. Remove input power cabling at CN1, CN2, CN3, CN11, CN17, & CN18 (See Figure 18).
4. Remove LED Power Supply Cables at CN9 and CN14 (See Figure 18).
5. Remove the two hex nuts that secure the main heat sink to the Power Supply Box screw studs (see
Figures 23a and 23b).
6. Remove the six screws that fasten the Power Supply Board onto the Power Supply Box (see Figure
24).