Position Sensor Pc Board Removal/Replacement/Adjustment - Analytical - OHAUS PA64 Service Manual

CHAPTER 3 MAINTENANCE PROCEDURES

3.3.17 Position Sensor PC Board Removal/Replacement/Adjustment - Analytical

When the Position Sensor PC Board is defective and requires replacement, proceed as follows:
1. Open the balance, and remove the
Load Cell.
2. Un-solder the thermistor wires
and ribbon cable. (See Figure
3-75.)
3. Remove the two inset screws
holding the Position Sensor
Board in place.
4. Remove the Position Sensor
Board, and install the
replacement. Insert the
screws previously removed.
Tighten the screws finger-tight to allow adjustment in Step 9.
5. Re-solder the wires. (See Figure 3-75.)
6. Place the Load Cell in position and insert the screws finger-tight, to facilitate Step 9.
7. Connect the cable from the Main PCB to the Position Sensor Board.
8. Operate the balance with the Weighing Pan in its normal position, but with the Top
Housing off. Power on using the middle button on the PCB.
The Position Sensor Board contains an Optical Sensor which must be positioned in
the Ratio Beam's center of travel for the balance to function properly.
9. Adjust the vertical position of the
Position Sensor Board: if it is too high
or too low, the display indicates Error
8.X. (See Figure 3-76.) Move the
board until the display indicates other
than 8.X.
10. Tighten the screws on the Position
Sensor Board. (See Figure 3-76.)
11. Insert and tighten the two remaining
screws to secure the Load Cell.
Check again that an Error 8.X is not
displayed. (If so, repeat Step 9.)
12. Disconnect the power. Install the
Load Cell Cover and close the
balance.
Ohaus Corporation www.ohaus.com
3-wire Ribbon Cable
Figure 3-75. Position Sensor Board
(Analytical).
NOTE:
Figure 3-76. Adjust Position Sensor Board
vertically until Err8.X does not appear.
3-28
Thermistor wires
are soldered on
Inset Screws
the bottom
Pioneer Balance Service Manual