Troxler 4640-B, Operation And Instruction Manual

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CLEANING THE TUNGSTEN SLIDING BLOCK
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If the tungsten sliding block is not kept clean, it may stick partially
or completely open when the source rod is raised to the safe
(shielded) position. This will result in high radiation levels near or
in line with the source rod opening on the bottom of the gauge.
After cleaning and reassembling the gauge as described below,
check the operation of the sliding block by pushing the source rod
into the measurement position, then returning it to the safe position.
You should hear a
click as the sliding block snaps shut. Inspect the
opening on the base of the gauge to confirm that the sliding block is
completely closed. If not, check that the sliding block spring was
properly installed after cleaning. If the sliding block still does not
close properly, immediately contact the nearest Troxler Service
Center.
CAUTION
Do not store or transport the gauge unless the sliding
block is completely closed. Increased radiation levels
may violate transportation regulations, and may cause
excessive personnel radiation exposure.
If the source rod becomes difficult to lower into the measurement
position or a
click is not heard when the source rod is raised to the
SAFE position, the sliding block may require cleaning. An
improperly operating sliding block may also result in erratic density
readings.
✓
With the source rod in the SAFE position, place the gauge on
its side.
✓
Clean the heads of the four screws that hold the bottom plate to
the gauge base. Using a screwdriver, remove the four screws
and the plate. Replace the plate if excessive wear is evident on
the inside surface of the plate.
✓
Remove the sliding block. Pay close attention to the position of
the block as it is removed. Clean the block and the cavity with a
stiff brush or rag soaked in alcohol.
Model 4640-B Appendix C–11