Removing The Printed Circuit Board - GE DigitalFlow DF868 Service Manual

4.3 Removing the Printed Circuit Board

All of the remaining maintenance procedures discussed in this chapter require removal of the printed circuit board.
Refer to Figure 8 on page 35 and Figure 9 on page 36 while completing the following tasks:
1. Remove the main power to the electronics console.
WARNING! The main power to the Model DF868 must be disconnected before proceeding.
2. Open the electronics console. For LVD compliant units, remove the two mounting screws and lift the clear plastic
shroud out of the electronics console. Remove the six mounting screws and lift the main aluminum shroud out of
the electronics console.
3. Disconnect the main power leads and the PC board ground wire from terminal block
the electrical connectors from all installed option cards and terminal blocks. Disconnect the twisted-pair display
backlight cable from connector
4. Using a 3/8 in. nutdriver or open-end wrench, remove the three short standoffs along the left side of the main
circuit board and the three long standoffs along the right side of the main circuit board.
5. While supporting the printed circuit board, remove the two screws or standoffs along the bottom edge of the
printed circuit board.
Note: For an LVD compliant meter with the clear plastic shroud over the electrical connectors, there will be
standoffs in these two locations. For meters not equipped with this shroud, there will be Phillips head screws in
these two locations.
6. Carefully lift the printed circuit board out of the enclosure. Continue to support the printed circuit board, as the
keypad and display cables are still connected to the rear of the board.
CAUTION! During this procedure, be very careful not to damage the upright components along the top
edge of the printed circuit board (see Figure 9 on page 36). Severe or repeated bending will break
the component leads.
7. Tilt the top of the printed circuit board forward, and mark the top edges of the two ribbon-cable connectors. Then,
remove these cables from their connectors on the rear of the board.
8. The printed circuit board is now free and may be removed to a clean work area.
If the printed circuit board is being replaced, proceed to the section on Installing the Printed Circuit Board (page 32)
now. Otherwise, refer to the appropriate section for instructions on Installing an Option Card (page 30), Replacing the
EPROM (below), or Replacing the LCD Display (page 31).
DigitalFlow™ Multipurpose Ultrasonic Liquid Flowmeter Service Manual
J2
on the left side of the PC board.
Chapter 4. Parts Replacement
TB1
on the PC board. Remove
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