Troxler 3430-M, Manual Of Operation And Instruction

Page: 106 / 142

TUNGSTEN SLIDING BLOCK
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 backscatter 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 your nearest Troxler Service
Center.
The tungsten sliding block may require cleaning if the source rod
becomes difficult to lower into the “measure” position or if a
click is
not heard when the source rod is raised to the SAFE position. An
improperly operating sliding block may also result in erratic or
incorrect density readings and increased radiation levels.
✓
With the source rod in the SAFE position, place the gauge on
its side.
✓
Clean the heads of the four screws holding the bottom plate to
the gauge base (Figure C-1). 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.
✓
To reduce radiological exposure, stand to one side of the gauge.
Paying close attention to the position of the sliding block,
remove the block. Clean the block and the cavity with a stiff
brush or rag soaked in alcohol or WD-40.
C-12
CAUTION
Do not store or transport the gauge unless the
sliding block is completely closed. Increased
radiation levels may violate transportation
regulations and cause excessive personnel radiation
exposure.