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FRU Disassembly/Assembly
This topic explains how to remove and replace many of the printer's Field Replaceable Units (FRUs). This topic covers procedures for FRUs that are difficult to remove or require special handling or precautions.

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1

The printer cabinet
Upper rear cover
1. Remove the four screws securing the upper rear cover in place.
Top cover Hinge frame Conical spring Hinge pin Door Retainer hooks Left side cover

Lower rear cover
Note Note that the lower rear cover clips underneath the printer frame. Lift the printer slightly to remove the lower rear cover in the next step.
Upper rear cover

1. Remove the four screws securing the lower rear cover in place. 2. Unlatch the temperature/humidity sensor assembly from the rear panel.

Top cover
1. Remove the upper rear cover first. 2. Remove the three screws securing the rear of the top cover in place. 3. The front of the top cover is held by metal tabs. Tilt the cover up from the rear, slide it back slightly and remove.
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Lower rear cover

Multi-purpose tray Left door 740-7-1

Figure 8

Removing cabinet covers

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2

Left door (for paper feeder access)
1. Open the left door. 2. Unhook the retaining strap from the door. 3. Unpin the door from the engine frame. Unpin the rear of the door first. Note the spring on the front hinge. The spring ends are different, so it must be oriented so that the wide end faces the front of the printer.

Left side cover
1. Lower the multi-purpose feeder tray. 2. Remove the upper rear cover and top cover. 3. Gently squeeze the plastic retaining hooks at each upper corner of the left side cover to unhook the cover from the printer frame. Tilt forward and remove the cover. 4. Multi-purpose feeder tray. Tilt the tray up slightly and squeeze the tray's retaining pins inward to free it from the print engine frame.

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3

Front door
1. Open the front door. 2. Remove the two screws securing each door hinge to the front door.
Toner level sensor board

Upper front cover
1. Remove the top cover. Remove the imaging unit. Cover the imaging unit to protect its photoconductive belt from light. 2. Remove the four screws securing the front covers. 3. Disconnect the front panel board's wiring harness and ground wire. 4. To separate the lower front cover from the upper front cover, remove the two screws securing them together.
Front door Upper front cover

Right side covers Rear Front

Bottom front cover (lift printer to remove)

Lower (lift printer to remove)
740-7-2

Figure 9

Removing cabinet covers

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Bottom front cover
Note The bottom front cover clips underneath the printer frame. Lift the printer slightly to remove the cover in the next step.

1. Open the front door. 2. Remove the three screws securing the bottom front cover in place. 3. Tilt the cover forward and remove it.

Toner level sensor board
1. Remove the top cover. Remove the imaging unit. photoconductive belt from light. Cover the imaging unit to protect its

2. Remove the three screws securing the toner level sensor board. 3. Disconnect the sensor board's wiring harness. Remove the sensor.

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5

Right side covers (front, rear and lower)
Remove the lower front cover and the front and rear right side covers before removing the right side lower cover. 1. Remove the paper tray.

Note

The lower side cover clips underneath the printer frame. Lift the printer slightly to remove the lower side cover in the next step.

2. Remove the two screws securing each of the front and rear right side covers in place. Remove the covers. 3. Remove the lower side cover.

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6

EMI shields
Use a magnetic screwdriver when removing the many screws securing EMI shields in place to avoid losing the screws in the printer. Note the placement of the shields and the routing of all cables prior to removing them. 1. Remove the upper rear cover and top cover as detailed in the earlier procedures "The printer cabinet" on page 2. 2. Remove the interconnect wiring shield by removing the six screws securing it in place. Lift and remove the shield. 3. Unplug the engine-to-image processor cable from the engine control board. 4. Remove the 13 screws securing the large EMI shield. Carefully tilt up the bottom of the shield and remove it. Ensure that no wiring harness hangs up on the shield. Reverse these steps to install the shields. Ensure that no cables are pinched by the shields as you install them.
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EMI shield

Interconnect wiring shield

740-7-3

Figure 10

Removing the EMI shields

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7

Paper feeder
Caution Do not tip the paper feeder or flip it over; waste toner will spill out.
5. Open the left side door to access the paper feeder. Slide it out. 6. With a screwdriver, back out the slide rail stop screws. There is one screw at the end of each slide rail.
Paper feeder Paper tray sensor board

7. Slide the paper feeder off the rails.

Paper tray sensor board
1. Remove the paper tray. 2. Remove the paper feeder as explained in the previous procedure. 3. Remove the two screws securing the sensor board and cover to the printer.
740-7-4

Back-out stop screws

4. Disconnect the wiring harness leading to the paper tray sensor board.

Figure 11 Removing the paper feeder and the paper tray sensor board

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8

Multi-purpose tray pick roller
The multi-purpose pick roller should be replaced whenever the cork separator pad is replaced. The expected life of each is about 30k prints. 1. Turn off the printer. 2. Open the left side door to access the paper feeder. Slide out the paper feeder. 3. With a small, narrow, flat-blade screwdriver, carefully release the snap-fit cover over the multi-purpose tray pick roller. Small access holes allow you to access the five retaining latches. 4. Slide the right-end pick roller retainer on its shaft about 75 mm (3 in.) toward the front of the printer. You may need to use a small flat-blade screw driver to release the retainer's hook from the groove in the shaft it locks into.
Latch

Latch Pick roller cover Latch Multi-Purpose tray pick roller

Pick roller retainer Retainer groove
740-7-5

Figure 12 Removing the multi-purpose tray pick roller

5. Slide the pick roller 50 mm (2 in.) on its shaft toward the front of the printer. Lift up and remove the pick roller. 6. Reverse these steps to install the pick roller. Position it with its flat side facing down. You will need to push down the cork separator pad to slide the pick roller retainer back until it locks in place.
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9

Cork separator pad
The cork separator pad should be replaced whenever the multi-purpose pick roller is replaced; the life is about 30k prints. 1. Turn off the printer. 2. Open the left side door to access the paper feeder. Slide out the paper feeder. 3. Grasp the paper guide and push in and down to the bottom of its travel, then tilt it forward. 4. With a small, narrow, flat-blade screwdriver, reach behind the cork separator pad and free the two retaining hooks holding the separator pad in place. Note the spring is under tension. Remove the separator pad and spring. 5. Install a new cork separator pad. Reverse these steps to install the cork separator pad.
Retaining hooks Spring Cork separator pad Paper guide
740-7-6

Paper guide

Figure 13

Removing the cork separator pad

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10

Cartridge selector/eject unit (right door)
1. Remove the right-side covers as explained in the earlier topic, "Right side covers (front, rear and lower)" on page 6. 2. Disconnect the cartridge selector/eject unit's wiring harness. 3. Counting from the rear of the shaft, remove the third E-ring from the cartridge selector/eject unit's shaft. 4. Remove the E-ring and keyed bushings from each end of the cartridge selector/ eject unit's shaft. 5. Remove the E-ring second from the front of the cartridge selector/eject unit's shaft.
Remove E-ring Cartridge selector/ eject unit (right door) Remove E-ring and bushing E-ring Keyed bushing Frame Spring Keyed Washer Washer Disconnect wiring harness

Caution In the next step, do not bend the frame to give additional clearance, as a damaged frame is not replaceable.

Remove E-ring and bushing

Washer Keyed Washer Spring Frame Keyed bushing E-ring

740-7-7

Figure 14 eject unit

Removing the cartridge selector/

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6. Unlatch the cartridge selector/eject unit and lower it halfway down to relieve spring pressure to enable moving the cartridge selector/eject unit's shaft. Slide the shaft forward until it clears the frame. If necessary, tap the rear end of the shaft with a screwdriver handle (no metal) to move it forward. 7. Unhook the tension springs from the engine frame at each end of the shaft. Note how they fasten to the frame and the right door. 8. Beginning at the rear, remove the cartridge selector/eject unit.

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Laser scanner
1. Remove the top cover as explained in topic, "Top cover" on page 2. 2. Disconnect the four wiring harnesses connected to the laser scanner. 3. Remove the three screws securing the laser scanner in place. Lift and remove the laser scanner. 4. Remove the EMI shield as detailed in the earlier procedure, "EMI shields" on page 7. 5. Disconnect the laser scanner's wiring harness from connector CN4 of the engine control board.
Shield Laser motor driver board Disconnect wiring harnesses Separate these two wiring harnesses to minimize possible crosstalk Remove three screws Laser scanner

Note

Cover the laser window slot leading to the imaging unit to protect the photoconductive belt from room light.
740-7-8

Figure 15 Removing the laser scanner and driver board

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13

Power supply
1. Remove the upper and lower rear covers and EMI shield as explained in the earlier topic, "The printer cabinet" on page 2. 2. Disconnect the three wiring harnesses connected to the power supply. Note for reassembly how the upper wiring harness passes through the cable restrain on the power supply fan. 3. Disconnect the power supply's fan from CN30 of the engine control board. 4. Remove the three screws securing the power supply in place. Lift and remove the power supply. Reverse these steps to install the power supply. Be sure to attach the bottom of the power supply to the tab in the printer frame. Otherwise the cabinet covers will not correctly reassemble.
Disconnect wiring harnesses Power supply

740-7-9

Figure 16

Removing the power supply

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14

Printer rear assemblies
Note If you are removing the engine control board to access an assembly underneath, disconnect the board's wiring harnesses and remove the board and mounting bracket as an assembly.
Engine control board bracket Engine control board

Engine control board
1. Remove the upper rear cover as explained in the earlier procedure, "Upper rear cover" on page 2. Remove the EMI shields as detailed in the earlier procedure "EMI shields" on page 7. 2. Disconnect the 28 harnesses leading to the engine control board. 3. Remove the six screws securing the board in place. Remove the engine control board by pulling it straight out.
IC 4
740-7-11

Figure 17 board

Removing the engine control

4. To remove the engine control board bracket, remove the four screws securing the bracket in place. Note for reassembly the bracket's alignment pin in its upper-left corner.

Note

Swap NVRAM IC4. IC4 stores print engine parameters and all consumable life counts and the engine print count. Connector CN28, next to IC4 has no corresponding plug.

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15

Main motor
The main motor can be differentiated from the toner cartridge drive motor and the paper-feed motor by its lack of heat sinks. 1. Remove the upper and lower rear covers and the left side cover as explained in the earlier procedure, "The printer cabinet" on page 2. Remove the EMI shields as detailed in the earlier procedure "EMI shields" on page 7. 2. Remove the engine control board and bracket as explained in the previous procedure, "Engine control board" on page 15. 3. Disconnect the motor's wiring harness. 4. Remove the four screws holding the main motor in place. Remove the motor.
Main motor Cleaning board

Toner cartridge drive motor

Paper feed motor

Paper feed motor

Figure 18 Removing the main motor, paperfeed motor, toner cartridge drive motor and cleaning board

1. Remove the upper and lower rear covers and the left side cover as explained in the earlier procedure, "The printer cabinet" on page 2. Remove the EMI shields as detailed in the earlier procedure "EMI shields" on page 7. 2. Remove the engine control board and bracket as explained in the previous procedure, "Engine control board" on page 15.
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3. Remove the four screws holding the paper feed motor in place. Remove the motor.

Toner cartridge drive motor
1. Remove the upper and lower rear covers and the left side cover as explained in the earlier procedure, "The printer cabinet" on page 2. Remove the EMI shields as detailed in the earlier procedure "EMI shields" on page 7. 2. Remove the engine control board and bracket as explained in the previous procedure, "Engine control board" on page 15. 3. Remove the four screws holding the toner cartridge drive motor in place. Remove the motor.

Cleaning board
1. Remove the upper and lower rear covers, and the left side cover as explained in the earlier procedure, "The printer cabinet" on page 2. Remove the EMI shields as detailed in the earlier procedure "EMI shields" on page 7. 2. Remove the engine control board and bracket as explained in the previous procedure, "Engine control board" on page 15. 3. Disconnect the cleaning board's wiring harness. 4. Remove the two screws securing the cleaning board in place. Remove the cleaning board. 5. To remove the cleaning board bracket, remove the two screws securing the bracket in place. Note for reassembly the brackets alignment pins.

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17

Toner cartridge drive unit
1. Remove the upper and lower rear covers and the left side cover as explained in the earlier procedure, "The printer cabinet" on page 2. Remove the EMI shields as detailed in the earlier procedure "EMI shields" on page 7. 2. Remove the power supply as explained in the earlier topic, "Power supply" on page 14. 3. Remove the engine control board and bracket as explained in the previous procedure, "Engine control board" on page 15. 4. Remove the cleaning board and its cleaning board bracket as an assembly as explained in the previous procedure, "Cleaning board" on page 17. 5. Remove the 10 screws securing the toner cartridge drive unit to the printer. Remove the drive unit.
Toner cartridge drive unit

Home position sensor

Left door-opened interlock switch Interlock 740-7-13 switch cover

Figure 19 Removing the toner cartridge drive unit, home position sensor and the left door interlock switch

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18

Home position sensor assembly and left door opened switch
1. Remove the upper and lower rear covers and left side cover as explained in the earlier procedure, "The printer cabinet" on page 2. 2. Remove the engine control board and bracket as explained in the previous procedure, "Engine control board" on page 15. 3. Accumulator belt home-position sensor assembly. Remove the two screws securing the home-position sensor assembly in place. 4. Left door-opened switch. Open the left door. Squeeze the interlock switch's cover to release it. Move it out of the way. 5. Disconnect the wiring harness leading to the interlock switch. 6. Remove the two screws securing the interlock switch in place. Remove the switch.

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19

Temperature/humidity sensor board
1. Remove the upper and lower rear covers and the left side cover as explained in the earlier procedure, "The printer cabinet" on page 2. 2. At the lower rear cover, slide out the white plastic housing containing the temperature/humidity sensor board. 3. Unclip the sensor board from its housing. Disconnect the sensor's wiring harness. Do not touch the surface of the humidity sensor. Reverse these step to install the temperature/humidity sensor board.

Housing

Lower rear cover

Temperature/humidity sensor board 740-7-14

Figure 20 Removing the temperature/ humidity sensor board

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20

Pre-exposure lamp
1. Turn off the printer. Remove the imaging unit. 2. Remove the screw securing the preexposure lamp in place. 3. Disconnect the pre-exposure lamp's wiring harness. Remove the lamp.

.

Pre-exposure lamp

Pre-transfer lamp
1. Turn off the printer. Remove the imaging unit. 2. Remove the E-ring securing the front end of the cleaning cam roller. Move the front end of the roller out of the way. 3. Remove the screw securing the pretransfer lamp in place. 4. Disconnect the pre-transfer lamp's wiring harness. Remove the lamp.
Pre-transfer lamp
740-7-15

Figure 21 Removing the pre-exposure lamp and pre-transfer lamp

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21

High-voltage board
1. Remove the upper rear cover and the left side cover as explained in the earlier topic, "The printer cabinet" on page 2. Remove the interconnect wiring shield as detailed in the earlier procedure "EMI shields" on page 7. 2. Remove the image processor board as explained in the later topic, "Image processor board" on page 28. 3. Remove the access plate on the left side of the card cage; it is held with three screws.
Card cage Be careful not to short harness here to nearby screw tip Wiring harnesses

Warning Be careful in the next two steps, the edges on the inside of the card cage are ragged and sharp and can cut you.
4. Remove the two screws securing the cable restraint of the front panel wiring harness. Note the orientation of the cable restraint for reassembly. 5. Carefully disconnect the wiring harness from its connector inside the card cage. Figure 22

Cut hazard here

High-voltage board
740-7-16

Removing the high-voltage board

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6. Remove the five screws securing the card cage in place. Two of the screws are reached through access holes in the card cage. 7. Slide out the card cage. Note for reassembly the large alignment pin behind the card cage. 8. Disconnect the wiring harness leading to the high-voltage board. Disconnect the highvoltage wires leading from the high-voltage board to the print engine assemblies. 9. Remove the four screws securing the high-voltage board to the printer. Remove the board.

Caution When installing the wiring harness retainer, be careful not to press the wiring harness against the tip of a nearby screw, which will short the harness. The bent edge of the restraint faces the front of the printer.
Reverse these steps to install the high-voltage board. Be sure to correctly place the card cage on its alignment pin.

Note

The colored orientation stripe of the front panel wiring harness must be oriented up to properly align with the connector inside the card cage.

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23

Tray guides
1. Turn off the printer. 2. Remove the imaging unit and the developer cartridges. Safely store the imaging unit. 3. Remove the lower front and rear printer covers, and the right, front, rear and lower covers.

Caution In the next step, take care not to damage the output tray full sensor flag.
4. Carefully tilt the printer onto its right side. 5. Remove the two screws securing each tray guide in place. Remove the guide. Reverse these steps to install the tray guides. Figure 23
Tray guides

740-7-17

Removing the tray guides

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24

Gear train
1. Turn off the printer. 2. Remove the imaging unit and the developer cartridges. Safely store the imaging unit. 3. Remove the lower front and rear printer covers, and the right front, rear and lower covers.

Note

In the next step, take care not to damage the output tray-full sensor flag.
Gear train Gear train retainer Frame cross member
740-7-18

4. Carefully tilt the printer onto its right side. 5. Remove the nine large-head screws securing the bottom pan in place. 6. Remove the frame cross member by removing the three screws securing it in place. 7. Remove the two screws securing the gear train restraint in place. 8. Remove the gears of the gear train. Reverse these steps to install the gear train.
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Figure 24

Removing the gear train

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25

Installing a network card
Note EtherTalk and LocalTalk protocols require you to attach the Ethernet cable to the printer with the printer powered off. After connection, turn on the printer. During the printer's boot-up process, the printer's network node address is resolved with the network.

Network card

1. Power down the printer. Do not unplug the printer; this preserves a ground path to dissipate static charges.

740-7-19

Figure 25 printer

Installing a network card in the

2. Remove the network card cover plate from the rear panel of the printer. 3. Slide the network card into the card slot and firmly push it in place. Secure it in place with two screws. Token Ring network card. Ensure that the transmission speed jumper on the printer's Token Ring network card is set for the speed of the Token Ring network. Not installed, sets the card for 16 Mbps (the most common configuration); installed, sets the card for 4 Mbps. 4. Connect the appropriate host interface cable to the network card. 5. Turn on the printer and print the Startup Page. It lists the installed memory and options.

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Note

Whenever you replace the network card, swap the NVRAM chip from the old board to the new board. It is the 8-pin, socketed IC. On the Ethernet PhaserShare Card, do not jumper SW1. Otherwise, the NVRAM contents will be cleared when the printer is powered-down.

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27

Image processor board
1. Power down the printer. Disconnect all host interface cables. 2. Remove the two screws securing the board's rear panel to the printer. 3. Grasp the rear panel by the knob and slide the board out of the printer card cage. Reverse these steps to reinstall the board.
NV RAM Boot ROM

Note

Swap components. If you are

replacing the image processor board, exchange the Boot ROM (PLCC), the Figure 26 Removing the image processor NVRAM chip (DIP) and the Real Time board Clock module. The components contains important customer-created parameters. The printer may not operate correctly without the components being swapped. Also, be sure to transfer the RAM DIMMs, PhaserShare card and SCSI card from the old board to the new board.
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Real Time clock

Image processor board

740-7-20

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28

SCSI riser board
1. Turn off the printer. Do not unplug the printer; this preserves a ground path to dissipate static charges. 2. Remove the image process board from the printer as explained in the earlier procedure "Image processor board" on page 28. 3. If the SCSI riser board is not already installed, a metal plate will hold its place on the rear panel. Remove the metal plate. Carefully install the SCSI riser board on its two rows of connectors and with its SCSI connector mounted through the cutout in the rear panel. Secure the SCSi connector with two screws. 4. Reinstall the image processor board. 5. Print a startup page to check its listing of the printer's SCSI capability. Figure 27
SCSI riser board

740-7-38

Installing a SCSI riser board

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29

Installing a Font DIMM
1. Turn off the printer. Do not unplug the printer; this preserves a ground path to dissipate static charges. 2. Remove the image process board from the printer as explained in the earlier procedure "Image processor board" on page 28. 3. Insert a Font DIMM in the Font DIMM connector labeled J540 and tilt the DIMM down until it locks in place. When properly inserted, a tab on each end of the connector slips into a hole on each end of the DIMM. Also, a pawl on each end of the connector latches around each end of the DIMM to lock it in place. 4. Reinstall the image processor board. 5. Print a startup page to check its listing of the printer's font capacity.
Image processor board PostScript ROM DIMM

Font DIMM

Font DIMM

a

b
740-7-2

Insert Font DIMM and close latch

Figure 28

Installing a Font DIMM

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30

Installing RAM DIMMs
1. Turn off the printer. Do not unplug the printer; this preserves a ground path to dissipate static charges. 2. Remove the image processor board from the printer as explained in the earlier procedure "Image processor board" on page 28.
RAM DIMMs

DIMM 1

Caution Do not install a RAM DIMM in the slot labeled FONT. Printer damage will result.
3. Insert a memory module in an empty connector labeled DIMM 1or DIMM 2 (or J780 or J781). When properly inserted, a tab on each end of the connector slips into a slot on each end of the RAM DIMM. 4. Reinstall the image processor board into the printer. 5. Print a startup page to check its listing of the printer's memory and options.

Image processor board

DIMM 2

a

b
740-7-22

Insert DIMM into connector

Figure 29

Installing RAM DIMMs

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31

Replacing the code ROM DIMM
1. Turn off the printer. Do not unplug the printer; this preserves a ground path to dissipate static charges. 2. Remove the PostScript ROM DIMM by spreading the pawls securing it in its connector. 3. Install the new PostScript code ROM DIMM. When properly inserted, a tab on each end of the connector slips into a slot on each end of the ROM DIMM. 4. Reinstall the image processor board. 5. Turn on the printer and print a startup page to check the printer's performance.
PostScript ROM DIMM Image processor board Font DIMM Latch DIMM connector

PostScript ROM DIMM

a

b

Insert DIMM and close latch

740-7-23

Figure 30

Installing the code ROM DIMM

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