Position Sensor Board - OHAUS PA64 Service Manual

CHAPTER 3 MAINTENANCE PROCEDURES
3.3.8 Load Cell Disassembly – Precision Balances
8. Unsolder and remove the four wires
shown in Figure 3-24. The two wires
at the bottom connect to the light
source. They must be re-soldered as
pictured here: white on left, red on
right. The two wires on the top
connect to the Temperature Sensor.
Their positions are not important.
11. Remove the three screws holding the
Position Sensor Board in place.
(The two on the right have washers.
The one on the left doesn't.)
12. Gently set the Position Sensor Board aside – avoid putting stress on the 3-wire
ribbon cable, which is soldered to the Contact Board.
13. If the Ratio Beam is to be removed, unsolder the 3-wire ribbon cable from
the Contact Board. (See Figure 3-25.)
Figure 3-25. Contact Board with ribbon cable.
14. Carefully pry the Contact Board off
the Load Cell frame, and tape it to
the Beam. Take care not to
stress or break the fine wires
connected to the Contact Board.
If they are broken, the Ratio Beam
must be replaced.
Note: The fine wires are glued to
a post on the Ratio Beam. (See
Figure 3-27.) This same glue
provides insulation. If the wires are disconnected from the Ratio Beam, the
insulation may be damaged, causing a short circuit. If this happens, the Ratio Beam
must be replaced.
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Screws holding

Position Sensor Board

Figure 3-24. Position Sensor Board.
Contact
Board
glued to
frame
Figure 3-26. Fine wires connected to the
Contact Board, and affixed to Ratio Beam.
Figure 3-27. Contact Board taped to Ratio
Beam after removal from frame.
3-10
Wires glued to post
on Ratio Beam
Pioneer™ Balances Service Manual
Solder
points