Quantum QT-740, Service Manual

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Chapter 2 Assembly & Installation
Models QT-740 & QT-750 - Service Manual
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CHECKING THE OBSTRUCTION SENSORS (ELEVATING TABLE ONLY)
On Model QT-750, the operation of the four (4) Obstruction Sensors (S3-S6) must
be verified at installation. The Obstruction Sensors are located at either end of
the left and right Transverse Assemblies below each tabletop rail (see Figure 10).
Proceed as follows:
1. While the table is driving down, have an assistant lift up the table top (grasp-
ing under the rail) at one corner of the table.
2. The table should stop driving down when the table top is lifted with a reason-
able amount of force.
3. To adjust obstruction sensors, remove the Table Top Assembly (refer to Table-
top Assembly/Installation procedure in this chapter).
4. Loosen the lower hex nut (underside of Bearing Rail) securing the switch to
the Bearing Rail. Turn the upper hex nut on obstruction switch clockwise to
increase sensitivity, counterclockwise to decrease sensitivity.
5. Re-tighten the lower hex nut when adjustment is correct.
6. Re-install Tabletop Assembly (refer to Tabletop Assembly/Installation proce-
dure in this chapter).
7. Repeat above steps for each of the other obstruction sensors.
POSITIVE BEAM LIMITATION (PBL) COLLIMATORS
For Positive Beam Limitation (PBL) Collimators and Elevating Tables only, verify
the Vertical SID Interlock feature is functioning properly as follows:
OBSTRUCTION
SENSOR
BEARING
RAIL
Figure 10. Obstruction Sensor (Typical)