Figure 9-14 Selecting The Vacuum Check Test - Tektronix Phaser 380 Service Manual

Figure 9-14 Selecting the vacuum check test

6. The test prompts you to measure the vacuum created in the
accumulator as it runs the vacuum pump for about 90 seconds. You
should see a vacuum of 51 cm Hg (20 in. Hg, 9.8 psi) created. As the
solenoid valve is energized the vacuum should bleed off to 0 in about
5.6 seconds. If the vacuum does not reach the expected value, there is
a leak in the vacuum system from the pump, the accumulator and
their plumbing or the vacuum pump is defective.
7. Connect the vacuum gauge to the outlet side of the solenoid valve (the
hose running between the valve and the cap/wipe/purge unit).
8.
Run the Purge Printhead Test from the Head Maintenance
test suite. When the solenoid valve is energized you should see the
vacuum gauge jump to the value 51 cm Hg (20 in. Hg, 9.8 psi) and
within 5.6 seconds bled off to 0. This allows you to check the action of
the vacuum as it is applied to the printhead; the cap/wipe/purge
assembly should be sharply sucked against the printhead faceplate. If
it is not, there may be an ink clog in the vacuum tube leading to the
cap/wipe/purge assembly or the cap/wipe/purge unit is not sealing
correctly to the printhead faceplate due to improper cap/wipe/purge
unit positioning or a bad gasket.
If the vacuum does not bleed off at all then the air valve is not opening properly
or the 7-mil orifice (a part of the valve solenoid) is blocked. If the printhead is hot,
such a condition can allow ink to be sucked into the vacuum system tubing. If the
vacuum bleeds off too quickly, then the cap/wipe/purge assembly is defective
or check for the cap/wipe/purge assembly is not sealing properly to the
faceplate. Check the cap/wipe/purge assembly is properly positioned by
performing the "Cap/wipe/purge assembly adjustments" on page 9-10 and the
"Printhead-to-drum spacing adjustment" on page 9-16.
Checks and Adjustments
Service Manual 9-25
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