HP 4200, 43 Service Manual bpl12626
6 Removing and replacing parts
Contents
Removal and replacement strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
Required tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
Before performing service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
After completing service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
Screws used in the printer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
Parts-removal tree. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
Printer input tray, and cabinet wheel locks . . . . . . . . . . . . . . . . . . . . 136
User-replaceable parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
Print cartridge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
Transfer roller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
Tray 1 pickup roller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
Tray 1 separation pad . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
Tray 2 feed rollers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
Covers, tray 1, and the rear output bin . . . . . . . . . . . . . . . . . . . . . . . . . . 143
Accessory covers and the tray 2 extension door. . . . . . . . . . . . . . . . 143
Formatter cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
Top cover. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
Right-side cover. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
Left-side cover. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
Tray 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
Rear output bin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
Control-panel display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
Control-panel overlay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
Control-panel assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
Internal components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
Firmware DIMM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
Formatter assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
Fuser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
Output delivery assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
Duplexing pendulum assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
Tray 2 media-size sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
Main cooling fan (left side). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
Cooling fan (right side; HP LaserJet 4300 series printer only) . . . . . 170
Laser/scanner assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
Print-cartridge motor (HP LaserJet 4300 series printer only) . . . . . . 175
Main motor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
Tray 2 lifter-drive assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
DC controller PCA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
Paper-pickup assembly, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183
Main drive assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
Power supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
Paper-feed belt assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
Q2431-90912 Chapter 6 Removing and replacing parts 131
Tray 1 paper-pickup assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
Paper feed assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
Registration assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
Transfer assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
500-sheet feeder assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
500-sheet feed rollers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
500-sheet feeder right-side cover . . . . . . . . . . . . . . . . . . . . . . . . 204
500-sheet feeder control PCA. . . . . . . . . . . . . . . . . . . . . . . . . . . 207
500-sheet feeder media-size sensor. . . . . . . . . . . . . . . . . . . . . . 208
500-sheet feeder lifter-drive assembly . . . . . . . . . . . . . . . . . . . . 209
500-sheet feeder paper-pickup drive assembly . . . . . . . . . . . . . 210
1,500-sheet feeder assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
1,500-sheet feeder feed rollers . . . . . . . . . . . . . . . . . . . . . . . . . . 214
1,500-sheet feeder separation roller . . . . . . . . . . . . . . . . . . . . . . 214
1,500-sheet feeder door . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
1,500-sheet feeder rear cover. . . . . . . . . . . . . . . . . . . . . . . . . . . 217
1,500-sheet feeder right-side cover. . . . . . . . . . . . . . . . . . . . . . . 218
1,500-sheet feeder control PCA . . . . . . . . . . . . . . . . . . . . . . . . . 220
1,500-sheet feeder media-size sensor . . . . . . . . . . . . . . . . . . . . 221
1,500-sheet feeder lifter-drive assembly . . . . . . . . . . . . . . . . . . . 222
1,500-sheet feeder paper-pickup drive assembly . . . . . . . . . . . . 225
132 Removing and replacing parts Q2431-90912
Removal and replacement strategy
This chapter describes how to remove, replace, and reassemble the major assemblies of the
printer. Replacement is generally the reverse of removal. To identify the left side and right side of
the printer, face tray 1 on the front of the unit.
WARNING! Unplug the power cord from the power outlet (at the wall receptacle) before attempting to service
the product. If you do not follow this warning, severe injury can result. Certain functional checks
during troubleshooting might require power to be supplied to the product. However, all power
should be turned off and the product should be unplugged when you remove any product
assemblies or components. Never operate or service the printer when the protective cover is
removed from the laser/scanner assembly. The reflected beams, although invisible, can damage
your eyes.
CAUTION The product contains components that are sensitive to electrostatic discharge (ESD). Always
perform service work at an ESD-protected workstation. If an ESD-protected workstation is not
available, discharge body static by grasping the printer chassis before touching an
ESD-sensitive component. Ground the printer chassis before servicing the product.
Required tools
● #2 Phillips screwdriver
● small flat-blade screwdriver
● needle-nose pliers
● ESD mat (if available; see the ESD caution above)
● penlight (optional)
● Tape (optional)
CAUTION A PoziDriv screwdriver will damage screw heads on the product. Use a #2 Phillips screwdriver.
Before performing service
● If possible, print a menu map and configuration page. See the “Menu map” on
page 240 and“Configuration page” on page 241.
● Remove all of the accessories and print media, the print cartridge, and tray 2 from
the product.
● Unplug the power cord from the power outlet at the wall receptacle.
● Place the product on an ESD mat, if one is available. If an ESD-protected
workstation is not available, discharge body static by grasping the printer chassis
before touching an ESD-sensitive component. Ground the printer chassis before
servicing the product
After completing service
● Reinstall the print cartridge (remove the print cartridge prior to transporting the
printer back to the customer).
● Reconnect all cables to the product.
● Replace all of the accessories and load the media.
● Print a configuration page and verify that the latest firmware is installed on the
printer. See “Downloading a remote firmware update” on page 63.
Q2431-90912 Chapter 6 Removing and replacing parts 133
Screws used in the printer
This table describes the screws used in the printer and provides guidelines to help determine
where each type of screw is used. The screws can vary in length depending on the thickness of
the material that is being fastened.
Always note where each type of screw is located and replace each one in its original location.
Hint When you are disassembling the product, place the screws into the chassis holes from which they
were removed. This prevents their loss, and ensures that the proper type and length of screw for
each location is used when the product is reassembled.
Table 36. Common fasteners used in this product
Drawing and description Purpose
This screw is used to f asten metal
to metal when good electrical
contact is needed. This screw
also provides high resistance to
loosening.
Phillips machine screw with captive star washer
This screw i s used to f asten sheet
metal or plastic to plastic frames
(the deep, coarsely spaced
threads provide an increased
holding capability while
Phillips screw with self-tapping threads
decreasing the possibility of
stripping the target hole).
Reinstal note: To install a self-tapping screw, first turn it counterclockwise to align it with the existing
thread pattern, and then carefully turn it clockwise to tighten it. You will feel resistance and hear the screw
click when it engages the existing threads in the hole. Do not overtighten the screw. If a self-tapping screwhole becomes stripped, repair the screw-hole or replace the affected assembly.
This screw i s used to f asten sheet
metal parts to the sheet metal
chassis. It spans large clearance
holes and distributes the load by
increasing the bearing surface.
Phillips washer-head machine screw with a broad, flat
washer attached to the screw head
Screw measurement guide
134 Removing and replacing parts Q2431-90912
Parts-removal tree
Use the following diagram to determine the order in which parts must be removed.
Print cartridge
Transfer roller
Control-panel overlay
Tray 1
Tray 2 feed rollers
Rear output bin
Formatter cover
Firmware DIMM
Formatter assembly (2 machine screws)
Accessory covers and the tray 2 extension door
Fuser
Tray 1 pickup roller
Tray 1 separation pad
Top cover
Note Some components in the parts-removal tree have a
Control-panel assembly
Right-side cov e r
superscript number listed next to the component name
(for example, “Right-side cover
1
”). The superscript
indicates that this component must be removed to gain
access to the transfer assembly and to the registration
roller assembly. Components with superscript letters are
removed in numerical order.
1
Components listed with superscripts
Left-side cover
7
Components listed with superscripts
Note: The formatter assembly and fuser are only listed once, but they must
be removed to gain access to some of the other components.
Tray 2 media-size sensor
Tray 2 lifter-drive assembly
Cooling fan (right side; HP LaserJet 4300 only)
Laser/scanner
Paper-pickup assembly
3
Print-cartridge motor (HP LaserJet 4300 only)
Main motor
DC controller assembly
5
Main drive assembly
1, 2, 5, 6
6
Registration-roller assembly
Output delivery assembly
8
Duplexing pendulum assembly
Main coolin g fan (left side)
Power supply
9
Paper-feed assembly
Tray 1 pickup assembly
1, 3, 4, 5, 6, 7, 8, 9, 10
10
Transfer assembly
2
4
Q2431-90912 Chapter 6 Removing and replacing parts 135
Printer input tray, and cabinet wheel locks
When the printer and input trays are placed on the cabinet stand, the printer and trays must be
locked together to prevent them from tipping over. This is not necessary (but it is recommended)
if the printer and trays are placed on a level work surface. When servicing the printer and
accessories, unlatch the locking mechanism and separate the printer and its accessory
components.
The cabinet stand includes lock for the wheels at its base. Make sure that the wheels are locked
when the printer is in place. The wheels should be unlocked only when the printer is being
relocated.
Figure 58. Location of printer, input trays, and cabinet wheel locks
136 Removing and replacing parts Q2431-90912
User-replaceable parts
Print cartridge
1. Open the control-panel door.
Figure 59. Print cartridge (1 of 2)
2. Firmly grasp the print cartridge and pull it up and out of the printer.
CAUTION Do not expose the print cartridge to bright light or direct sunlight for long periods of time. This can
damage the cartridge, which will result in print-quality defects. If the cartridge must be removed
from the printer for an extended amount of time, cover it and keep it out of bright light or direct
sunlight.
Figure 60. Print cartridge (2 of 2)
Q2431-90912 Chapter 6 Removing and replacing parts 137
Transfer roller
1. Open the control-panel door and tray 1.
CAUTION Do not touch the black rubber on the roller. Skin oils on the roller can cause print-quality problems.
The use of disposable gloves is recommended when you remove the transfer roller.
2. Use a flat-blade screwdriver to lift the left end of the metal shaft out of place near the blue
gear. Slide the transfer roller to the left to remove it.
Figure 61. Transfer roller
Reinstall note When you install the transfer roller, make sure that the black collar on the left side is oriented
correctly, with the open end face down (the solid end is face up).
138 Removing and replacing parts Q2431-90912
Tray 1 pickup ro ller
Note If the optional envelope feeder accessory is installed, press the release button that is on the left
side and remove it. Then proceed to step 2.
1. Remove the front accessory cover (callout 1).
11
Figure 62. Tray 1 pickup roller (1 of 2)
2. Release the pickup roller by sliding apart the latches that are located on each side at the top
of the roller. Lift the roller out of the opening.
222
Figure 63. Tray 1 pickup roller (2 of 2)
Reinstall note When you install the pickup roller, place the two pivot pins in the lower mounting slots (callout 2)
and rotate the roller into the printer until it snaps into place.
Q2431-90912 Chapter 6 Removing and replacing parts 139
Tray 1 separation pad
Note If the optional envelope feeder accessory is installed, press the release button that is on the left
side and remove it. Then proceed to step 2.
1. Remove the front accessory cover (not shown). See “Accessory covers and the tray 2
extension door” on page 143.
2. Insert the tip of a a small flat-blade screwdriver under the tray 1 separation pad.
3. Carefully twist the screwdriver to dislodge the separation pad. Remove the tray 1 separation
pad.
Figure 64. Tray 1 separation pad
140 Removing and replacing parts Q2431-90912
Tray 2 feed rollers
1. Remove tray 2 and place it on a level work surface. Locate and open the cover (arrow) that is
next to the roller in tray 2.
Figure 65. Tray 2 feed rollers (1 of 4)
2. Pinch the blue latch that is on the left side of the roller. Slide the roller off of the shaft
(arrows).
11
Figure 66. Tray 2 feed rollers (2 of 4)
CAUTION When you install the roller, make sure that it locks into place. Verify that the roller is correctly
oriented, and that the round, black spacer next to the roller is correctly positioned against the
locking pin on the shaft (callout 1).
Q2431-90912 Chapter 6 Removing and replacing parts 141
WARNING! Do not allow the front of the printer to extend beyond the edge of the work surface. The printer
can become unbalanced and fall, which can cause damage to the printer or personal injury to the
service technician.
3. Move the front of the printer to the edge of the work surface for better access to the feed
roller. To find the rollers, look up into the inside of the opening that was created when you
removed tray 2.
Figure 67. Tray 2 feed rollers (3 of 4)
4. Pinch the blue latch on the left side of the feed roller. Slide the roller off of the shaft. You
might need to rotate the roller in order to pinch the latch.
22
Figure 68. Tray 2 feed rollers (4 of 4)
5. Repeat the previous step for the remaining white pickup roller.
Reinstall note When you install a roller, make sure that it locks into place on the tabs that are on the drive gear
(callout 2).
142 Removing and replacing parts Q2431-90912
Covers, tray 1, and the rear output bin
Accessory covers and the tra y 2 extension door
Note Accessory covers will not be in place if any installed accessories (for example, the optional
stapler/stacker) have been removed to service the printer.
1. Grasp the top accessory cover (the mounting position for the optional stapler/stacker or
stacker). Rotate the cover toward the front of the printer to release it, and then lift it up to
remove it.
Figure 69. Accessory covers (1 of 4)
2. Open tray 1. Grasp the front accessory cover (the mounting position for the optional
envelope feeder) and pull it straight out of the printer.
Figure 70. Accessory covers (2 of 4)
Q2431-90912 Chapter 6 Removing and replacing parts 143
3. Grasp the rear accessory cover (the mounting position for the optional duplexer) and pull it
straight out of the printer.
Figure 71. Accessory covers (3 of 4)
4. Rotate the tray 2 extension door to the horizontal position. Lift up on the right side of the door
to unlock its pivot bar. Slide the left-side pivot pin out of its retainer and remove the door.
Figure 72. Accessory covers (4 of 4)
144 Removing and replacing parts Q2431-90912
Formatter cover
1. Grasp the formatter cover.
2. Pull the cover straight back and away from the printer.
Figure 73. Formatter cover
Q2431-90912 Chapter 6 Removing and replacing parts 145
Top cover
Note If the optional stapler/stacker or stacker accessory is installed, lift it straight up and off of the printer
to remove it. Then proceed to step 2.
1. Remove the top accessory cover. See “Accessory covers and the tray 2 extension door” on
page 143.
2. Remove the two rear mounting screws (callout 1).
21
Figure 74. Top cover (1 of 5)
3. Open the print-cartridge door. Remove the front two mounting screws (callout 2).
22
Figure 75. Top cover (2 of 5)
146 Removing and replacing parts Q2431-90912
4. Use needle-nose pliers to release the print-cartridge drive-arm (callout 3).
Hint Push the drive-arm back into the printer to avoid damaging it when you remove the top cover.
33
Figure 76. Top cover (3 of 5)
5. Open tray 1 and the rear door. Grasp the top cover and carefully rotate the left edge up and
away from the printer. Do not apply stress to the control-panel wire-harness (callout 4) when
rotating the top cover away from the printer.
44
Figure 77. Top cover (4 of 5)
Q2431-90912 Chapter 6 Removing and replacing parts 147
6. Disconnect the control-panel wire-harness (callout 5) from the DC controller PCA. Remove
the top cover.
Figure 78. Top cover (5 of 5)
35
CAUTION When the top cover is re-installed, make sure that the wire-harnesses are properly routed through
the cable guides. If the wire-harnesses are not properly routed, they can be damaged when the
top cover is installed.
Hint The control-panel wire-harness connector can easily be disconnected when you install the top
cover . If the control panel does not work after the top cover is installed, verify that the wire-harness
connector is fully seated into its DC controller PCA connector.
148 Removing and replacing parts Q2431-90912
Right-side cover
1. Remove the following assemblies:
● Formatter cover. See “Formatter cover” on page 145.
● Top cover. See “Top cover” on page 146.
2. Release the upper right-side cover-locking tab near the formatter (callout 1).
11
Figure 79. Right-side cover (1 of 4)
3. Locate the arrow that is embossed on the tray-number indicator. Use a small flat-blade
screwdriver to push in on the lower cover-locking tab to release it.
Figure 80. Right-side cover (2 of 4)
Q2431-90912 Chapter 6 Removing and replacing parts 149
4. Locate the arrow (callout 2) that is embossed on the pickup gear cover near the optional
envelope feeder power connector (not shown; open tray 1 to locate this arrow). Use a small
flat-blade screwdriver to push in on the locking tab to release it
22
Figure 81. Right-side cover (3 of 4)
5. Open the formatter door and rotate the right-side cover away from the printer and lift it up to
remove it.
23
Figure 82. Right-side cover (4 of 4)
Reinstall note When you install the right-side cover, verify that the power-switch arm locks onto the switch
connecting rod (callout 3).
150 Removing and replacing parts Q2431-90912
Left-side cover
1. Remove the top cover. See “Top cover” on page 146.
2. Release the upper (callout 1) and front left-side cover-locking tabs.
11
Figure 83. Left-side cover (1 of 2)
3. Rotate the top of the cover away from the printer and lift the cover up to remove it.
Figure 84. Left-side cover (2 of 2)
Q2431-90912 Chapter 6 Removing and replacing parts 151
Tray 1
1. Open tray 1. Use your fingers to gently pry the paper-guide slide-pin hinges out of the hinge
slots on the tray 1 door to release the pins.
Figure 85. Tray 1 (1 of 6)
2. Slide the tray 1 door to the right and remove it.
111
2
Figure 86. Tray 1 (2 of 6)
Reinstall note When you install the tray 1 door, the door-stop pin (callout 1) must be installed in the stop
receptacle on the door (callout 2) so that the door will open and close properly.
152 Removing and replacing parts Q2431-90912
3. Firmly pull both sides of the tray 1 sensor arm cover down to release it from the shaft.
Figure 87. Tray 1 (3 of 6)
Reinstall note When the tray 1 sensor cover is installed, verify that the sensor arms move freely.
Note Be sure to look at how the spring (callout 3) is positioned before removing it.
4. Rotate tray 1 upward and release the return spring (callout 3) from the bottom of tray 1.
33
Figure 88. Tray 1 (4 of 6)
Q2431-90912 Chapter 6 Removing and replacing parts 153
5. Rotate the paper guide down and away from the printer to release the left paper-guide hinge.
Figure 89. Tray 1 (5 of 6)
6. Slide the paper guide to the left to remove it.
Figure 90. Tray 1 (6 of 6)
Hint Tape the return spring in place on tray 1 so that you will not lose it.
Reinstall note When installing the tray 1 paper guide, hook the short end of the return spring in the small notch
located below the right-side hinge-pin receptacle.
154 Removing and replacing parts Q2431-90912
Rear output bin
Note If the optional duplexer accessory is installed, lift it up slightly and pull it away from the printer to
remove it.
1. Open the rear output bin. Use your finger to squeeze the hinge pin (formatter side) out of its
mounting hole.
Figure 91. Rear output bin (1 of 2)
2. Rotate the output bin away from the printer until the right hinge pin is released, and then
remove the output bin.
Figure 92. Rear output bin (2 of 2)
Q2431-90912 Chapter 6 Removing and replacing parts 155
Control-panel display
Control-panel overlay
1. Use a small flat-blade screwdriver to carefully pry the top of the control-panel overlay
(circled; callout 1) away from the printer.
2. Remove the overlay.
11
Figure 93. Control-panel overlay
156 Removing and replacing parts Q2431-90912
Control-panel assembly
CAUTION Always remove the top cover before attempting to remove the control panel. If you drop any of
the control-panel mounting screws into the printer when you remove the control panel, they might
be difficult to recover. Severe damage to the printer can result if the power is turned on when
loose screws are inside the unit.
1. Remove the top cover. See “Top cover” on page 146.
2. Place the top cover upside-down on a padded work surface.
3. Remove six screws (callout 1).
11
Figure 94. Control-panel assembly (1 of 4)
Q2431-90912 Chapter 6 Removing and replacing parts 157
4. Raise the top cover so that the print cartridge door begins to open. This allows the door-open
flag (callout 2) on the print cartridge door to clear the opening (callout 3) in the top cover.
Remove the control panel PCA cover.
3
232
Figure 95. Control-panel assembly (2 of 4)
5. Remove the grounding-strip screw and clip (callout 4).
Reinstall note When you install the grounding strip (callout 5), do not forget to replace the protective clip. If the
grounding strip is installed without the clip, tightening the screw will damage the grounding strip.
5445
Figure 96. Control-panel assembly (3 of 4)
158 Removing and replacing parts Q2431-90912
CAUTION The product contains components that are sensitive to electrostatic discharge (ESD). Always
perform service work at an ESD-protected workstation.
6. Use your fingers to gently pry the front of the print-cartridge door away from the controlpanel display to release the retainer clip (callout 6). Unplug the control-panel wire-harness
(callout 7). Remove the control panel.
7
566
Figure 97. Control-panel assembly (4 of 4)
Reinstall note When the control-panel display is installed, verify that the wire-harness is placed in the cable
guide under the grounding strip.
Q2431-90912 Chapter 6 Removing and replacing parts 159
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