49
11.7 Coated aluminium parts
PA 11: Rilsan = blue, grey or yellow colour
The coating should be subject to regular and careful inspection.
The continued used of the apparatus should not be permitted
if inspection reveals that the protective material has become
damaged to the extend that the underlying protected metal is
visible, until such damage has been satisfactorily repaired.
11.8 Winding action becoming stiff
If after repeated use the winding action is becoming slightly
stiff apply the following simple process:
• engage the tape cleaner (position “UP”), with the sensor
retained in the storage tube,
• slacken the tape a few turns, typically 10,
• gently shake the instrument to free up the tape within the
tape housing,
• wind the tape again and disengage the tape cleaner (position
“DOWN”).
11.9 Electrical checking of the tape assembly
Test for grounding
• Remove the battery holder as described in section 10.3.
Measure the resistance between the ground (-) terminal
(as shown on Figure 11-1) of the electronic circuit and the
tube of the sensing probe; the resistance should be less
than 10
Ω. If it is higher, the steel tape might be broken or
the connection between the sensing probe circuit and the
sensing probe tube might be interrupted.
Test for short-circuit
• Disconnect the tape at both ends: display unit side and
sensing probe side (see sections 10.4.1 and 10.4.2).
• Measure the resistance between each conductor red-white,
red-black, white-black. This resistance should be innite as
an open circuit. If not, the tape might be defective.
Test for open-circuit (continuity)
• Disconnect the tape at the sensing probe side
(see 10.4.1).
• Measure the resistance of each conductor of the
tape (between red and red, white and white, etc.).
• The resistance should be less than 15
Ω. If not,
the tape might be broken. To replace the tape see
section 10.4.
Figure 11-1
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