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TB006 Rev1 Replacing the LCD Backlight & Inverter
Xentek Inverter replacement OLDER M400 & M15 controls
Overview
This document describes the steps needed to replace the fluorescent tube in the LCD display and replace the
Allus brand inverter with the Xentek inverter included with these instructions This procedure is intended for
qualified Centroid Technicians only
Dates Allus inverters were in use M400 08/96 to 06/97
 M15 02/96 to 07/97
Disassemble the Front of the Control
Remove all the screws from the front panel
Loosen the front panel Shift slightly to the right and then lean forward
Remove the ribbon cable from the LCD descrambler board and the power cables from the inverter
board
Remove the keyboard cable MPG cable and the jog pic cable
Lay the front panel down on the table in front of you and remove the old inverter by squeezing the
plastic standoffs with needle nose pliers
Remove the defective backlight and replace
Refer to the above diagram to replace
the fluorescent bulb with a new one
Straighten the tabs that secure the back plate of the LCD
Remove the four 4 screws that secure the back plate
Gently lift the back plate off the LCD Pay particular attention to the way the reflective material
around the bulb is to be replaced
Remove the old backlight and replace with the new one The new bulb comes mounted in a false
LCD case for shipping purposes Follow steps 1 3 to secure the new bulb from the false LCD panel
Replace the back plate and secure it with the tabs and four 4 screws
Mount the replacement inverter assembly to the existing standoffs
CONTINUE WITH THE REPLACEMENT OF THE XENTEK INVERTER See page two
Mounting the new inverter
The replacement inverter is manufactured by Xentek and is already mounted on a card that is the same size
as the Allus inverter Snap the new Xentek onto the existing standoffs mounted on the back of the LCD display
Diagram 2
Wiring / Connection
Plug the LCD display cable into the inverter; making sure that the white wire hot is oriented as shown below
* IMPORTANT you may need to reverse the white and gray wires in the plug in order to align the white wire
with the edge of the inverter and closest to the surface mount capacitor Carefully swap the wires within the
plug with a pick by gently lifting the plastic tabs on the plug which holds the wires in place and tug on the
wire After the wires have been swapped and plugged in make sure they are secure by gently pulling on each
wire and seeing that the wire doesn't pull out of the plug
*Cut the red black and yellow twisted wires that connect the power supply to the Allus Inverter that you're
removing
*Seal the bare ends with the enclosed heat shrink tubing; a lighter or other heat source will work great to seal
the wires with the tubing
*Lastly make sure that the BLACK power wire goes to the PC power supply inside the console on one of the
two GND terminals The YELLOW power wire goes to the +V terminal +12 Vdc This replacement cable has
been modified at Centroid and is included with the inverter
You are ready to reassemble the control in reverse of the disassemble instructions
Document History
Rev1 Created on 1998 02 26