Xerox Phaser 8500, Service Manual

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4-40 Phaser 8400/8500/8550/8560 Color Printer Service Manual
General Troubleshooting
This test does a chase using a special sheet of preprinted media and records
the y-axis following error.
This test modifies the Y-Axis servo loop so that it is unstable and oscillates.
The oscillation frequency is recorded while the drum is advanced for two
revolutions. Checks for correct belt tension and variations in tension during
operation.
Y-Axis Belt Slip
R# Definition
Typical
Value
(8400) Typical
Value (8500/
8550/8560)
Actions
0 Initial Peak Y-Axis
FE (mpts) 0 to 12000 1200 to 8000 Reports the amplitude of the
first Y-Axis following error
peak.
1 Max Following
Peak Y-Axis FE
(mpts) 0 to 11000 1100 to 7500 Reports the amplitude of the
maximum Y-Axis FE peak after
the first.
2 Average Y-Axis FE
(mpts) 0 to 4000 2200 to 3500 Reports the average of the Y-
Axis following error during the
roller down portion of the
transfix operation.
Y-Axis Belt Tension
R# Definition
Typical
Value
(8400) Typical
Value (8500/
8550/8560)
Actions
0 Min Resonant
Frequency (hz) 10 to 150 4.5 to 175 Reports the min resonant
frequency over the data set.
1 Max Resonant
Frequency (hz) 175 to
3000 -4400 to
10000 Reports the max resonant
frequency over the data set.
2 Min Resonant
Frequency Revs
(revs) Reports the number of full Y-
Axis revs required to locate the
min frequency configuration.
3 Min Resonant
Frequency Angle
(deg) -0.001 to -
0.2 -33 to -20 Reports the amount of
additional Y-Axis rotation
required to locate the min
frequency configuration.