OHAUS Pioneer PA64, Service Manual

Page: 37 / 116

CHAPTER 3 MAINTENANCE PROCEDURES
Pioneer
™ Balance Service Manual
3-13 Ohaus Corporation www.ohaus.com
3.3.9 Position Sensor Board Removal/Replacement/Adjustment
– Precision
If the Position Sensor Board is defective and requires replacement, proceed as follows:
1. Open the balance, and remove the Load Cell.
2. Un-solder the wires that attach to
the Position Sensor Board. The 3-
wire Ribbon Cable is connected to
the Contact Board. The two white
wires at the top are thermistor
wires: polarity is not important. The
two wires at the bottom-right must
be placed back in their original
position. (See Figure 3-33.)
Figure 3-33. Position Sensor Board.
3. Remove the three screws holding the Position Sensor Board in place.
(The two on the right have washer
s. The one on the left doesn’t.)
4. Remove the Position Sensor Board, and install the replacement. Insert all screws
previously removed. Tighten the screws finger-tight to allow adjustment in Step 9.
5. Re-solder all wires. (See Figure 3-33.)
6. Place the Load Cell in position and mount it with one screw.
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
cover off. Power on using the middle button on the PCB.
NOTE:
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 3-34.) Move it until the
display indicates
other than 8.X. If
there is an IDNR error, fix this error
first, and then check that an Error
8.X is not displayed.
10. Tighten the screws on the Position
Sensor Board. (See Figure 3-35.)
Figure 3-34. Adjust position of Sensor Board
until Err8.X does not appear.
Note : A 2.5mm Allen Key can be cut to fit the
space between the Housing and the Position
Sensor Board.
3-wire Ribbon
Cable
White, Red
Thermistor cables