C
HAPTER
3. M
AINTENANCE
P
ROCEDURES
3-85
02.9628.0010
CONFIDENTIAL
7-Oct-97
3.3.5.5
Motherboard Removal and Replacement
Parts:
1 EA
PCB ASSY, VL4 MOTHER (MBD) (24.9628.0053)
Tools:
Screwdriver, Phillips #1
Screwdriver, Phillips #2
To remove and replace motherboard:
Step 1.
Remove power to luminaire.
Step 2.
Remove both air filters and chassis covers.
a. At each electronics chassis air filter, while pressing down on
filter, pop out top of filter from chassis and fully remove
filters.
b. Remove eight 6-32x5/16"PPB screws that secure two top
covers to chassis and remove covers.
Step 3.
Remove low voltage supply and universal control PCBs
(Figure 3-31).
a. At card retainer, press down on spring release and open
retainer.
b. Pull out low voltage power supply PCB and universal
control PCB.
Step 4.
Remove power supply.
a. At bottom of chassis, in countersink, remove
6-32x5/16"PPB screw securing power supply
(Figure 3-27).
b. Pull out power supply.
Step 5.
Remove voltage selector PCB (Figure 3-29).
Step 6.
Remove yoke bearing frame.
a. At yoke bearing frame, remove four 6-32x5/16"PPB screws
that secure frame to flanges on top of chassis.
b. At bottom of chassis, remove five or six 6-32x5/16"PPB
screws that secure yoke bearing frame to chassis bottom
(depending on year of manufacture, luminaire was
constructed with either five or six bottom retaining screws).
c. Pivot end of yoke bearing frame closest to transformer away
from transformer and disconnect 8-pin MTA connector
from motherboard header marked MB-P7.
