![background image](http://html.mh-extra.com/html/tektronix/phaser-840/phaser-840_service-manual_1078591189.webp)
178
Phaser 840 and 850 Color Printers
2: Weak/missing jet
.
This print shows which jets are not
outputting enough, if any, ink compared to
its neighboring jets. Note that the yellow
jets’ bands have a small amount of cyan
ink added to them, which tints them green,
to make them more visible.
Look for:
No interlacing is used in this
print; expect light/dark variation between
jets. Look for
much
lighter colored vertical
bands in the horizontal bars. Weak jets in
the yellow band are distinguished by a
cyan tint.
Causes
: A jet may be partially clogged;
perform printhead clean/purge cycles on
the printhead to remove contaminants
from the poor-performing jet. Test the
vacuum system of the cap/wipe/purge
system. Turn the printer off for 4 to 6
hours (or overnight, if practical). Then
perform a clean/purge cycle again. As a
last resort, replace the printhead.
3: Color Bands, RGBK Dither
.
The large, secondary colored areas in this
print reveal banding and weak jets.
Look for:
Vertical “bars” or bands of
much
lighter color or a different hue
running in-line in one or more of the solid
fills.
Causes:
Banding is caused by
color-to-color misregistration. Ensure the
printhead-to-drum spacing is correct.
Then use the PC diagnostics to ensure
that the printhead and drum thermals are
correct. A weak jet can also cause
banding; refer to the
Weak/missing Jets
test print. Make sure that the drum
temperature sensor is correctly mounted
and in proper, even contact with the drum.
If necessary, remove the sensor and
check it for an accumulation of debris at its
contact point. As a last resort, replace the
printhead.
1 2 3 4
6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88
5
1 2 3 4
6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88
5
1 2 3 4
6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88
5
74 75 76 77 78 79 80
Weak jet
9923-114
1 2 3 4
6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88
5
9923-115
Banding
Summary of Contents for Phaser 840
Page 11: ...xii Phaser 840 and 850 Color Printers ...
Page 65: ...54 Phaser 840 and 850 Color Printers ...
Page 101: ...90 Phaser 840 and 850 Color Printers ...
Page 125: ...114 Phaser 840 and 850 Color Printers ...
Page 134: ...Service Guide 123 Clearing PostScript NVRAM menu item ...
Page 135: ...124 Phaser 840 and 850 Color Printers ...
Page 166: ...Service Guide 155 Figure 1 Cabinet FRUs 7 5 6 8 1 2 4 0388 21 3 9 9 ...
Page 170: ...Service Guide 159 Figure 3 Paper path FRUs 0388 80 2 1 5 11 10 9 12 6 4 3 7 13 8 11a 11b ...
Page 172: ...Service Guide 161 Figure 4 Motor and fan FRUs 0388 14 7 4 3 5 6 2 1 ...
Page 174: ...Service Guide 163 Figure 5 Circuit board FRUs 4 3 5 2 1 9 7 6 8 10 11 13 0388 81 12 7a ...
Page 176: ...Service Guide 165 Figure 6 Solenoid and clutch FRUs 4 5 3 2 1 0388 23 ...
Page 182: ...Service Guide 171 Figure 9 High capacity PaperTray 0388 65a 1 2 ...