Roche Diagnostics May 2009
Service Manual · Version 9.0 D-99
cobas b 221 system 7 Troubleshooting
Important test routines
Place syringe: This function is used to check the needle position.
It should be centered in the retainer.
If the needle projects too far, it is more difficult to attach a sample container. If the
needle is too far back, there is a danger that the sample container will fall off.
If the needle is not centered in the container, a "T&D needle calibration" must be
performed. If this is not successful, perform the following actions:
o Replace needle.
e
Replacing the needle on page 4-23.
o Replace T&D disk.
e
Replacing the T&D disk on page 4-26.
o Replace sample inlet path.
e
Replacing the sample inlet path on page 4-24.
o Replace T&D module.
e
Replacing the T&D module on page 4-21.
Aspirate from syringe: This function is used for visual inspection of the needle (bent, broken).
Peristaltic pumps
h At the ready screen, press
[System] > [Component test] > [Aggregates] > [Peristaltic pumps].
Overview This test function tests the function of the three peristaltic pumps (cobas b 221<1>–
<4> systems only have one peristaltic pump). The following features must be noted
here:
Noise check: If a pump is too loud, this indicates that the pump head may be eccentric – the pump
head of the relevant pump must be replaced.
In addition, an excessively noisy pump can indicate that a pump tube is too tightly
seated – the pump tube of the relvant pump must be replaced.
Direction of rotation: After replace a peristaltic pump the correct direction of rotation must be checked
with the test – if the direction of rotation is reversed, the pump is incorrectly
connected.
Tubing paths: This test function can often be useful as a support when testing the tubing, because it
allows precise control of the pumps.
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