GE AquaTrans AT868, User Manual

Page: 93 / 158

September 2004
7-4 Parts Replacement
Replacing the User
Program
The Model AT868’s User Program is stored on an erasable
programmable read-only memory (EPROM) chip. The EPROM,
which is designated as component
U4
, is mounted in a socket on the
rear of the Channel 1 board. EPROM replacement may be required to
replace a defective chip or to upgrade to a newer software version.
To replace the User Program , refer to Figure 7-1 on page 7-7 and
Figure 7-2 on page 7-8 and complete the following steps:
Accessing the EPROM
1.
Disconnect the power to the AT868 and move the electronics
enclosure to a flat service.
!WARNING!
The main power to the Model AT868 must be disconnected
before proceeding.
2.
Loosen the six set screws on the front cover. Remove the front
cover.
3.
Remove the plastic shroud by removing the two screws that hold it
in place.
4.
Remove the four mounting screws on the LCD/keypad board.
Make sure you remove the flat and lock washers with the screws.
5.
Grasp the LCD/keypad board by the side edges and carefully pull
it straight upward until it comes free from the Channel 1 board
below it.
6.
Disconnect the keypad ribbon on the board below by sliding the
tabs on the connector upward and pulling the ribbon cable out.
7.
Remove the four standoffs in the corners of the Channel 1 board.
8.
Remove the screw in the middle of the Channel 1 board.
9.
Carefully remove the Channel 1 board from the connectors on the
Channel 2 board below it.