09/20078-6 Phaser 8860/8860MFP Service ManualSystem ElectronicsInitial IssueTheory of OperationSystem ElectronicsThe Phaser 8860MFP has two controller boards: the main board, contained in the ElectronicsModule, and the Exit Module Control Board. For both models, the main board controls allimage processing by way of an integrated daughter board. The main board also controls net-work functionality, PS and PCL interpretation, memory, job management, device managementinterfaces and a host of other services. The Exit Module Control Board, exclusive to the8860MFP, provides low level motor control for the Exit Module components. The 8860MFPalso contains a Scanner Power Supply located next to the Exit Module Control Board on theBackframe (see Figure 1). This supplies power to the Scanner, DADF, and the Exit Modulemotors.For more information, or block diagrams showing the interaction between the system electron-ics, see the Wiring section of the manual.NOTE: Although the Control Panel is part of the Scanner Assemby on the 886MFP, it receivespower from the Electronics Module power supply.Figure 1 Electronics LocationsExit Module Control BoardThe 8860MFP Exit Module Control Board controls motor and paper path functions for the8860MFP Exit Module. Once the print process is complete and the media is ready to exit theIOT, the primary controller relinquishes control to the Exit Module Control Board. The Exit Mod-ule Control Board is also the connection point for the Output Tray Full Sensor, Cover Interlock,Exit Module elevator carriage, and exit sensors and flags.Scanner Power SupplyThe 8860MFP Scanner Power Supply supplies power to the Scanner and Exit Module assem-blies using the following voltages:• +24 V to the Scanner• +24 V and +5 V to the Exit Module Control BoardThe Electronics Module enables or disables the Scanner Power Supply using the power supplyenable line for functions such as Intelligent Ready and standby functions. The Control Panelreceives power from the power supply contained in the Electronics Module.Electronics ModuleThe Electronics Module includes the main board, image processing board, power controlboard, and the power supply. The Electronics Module is replaced as one assembly and isunique for each model.The imaging process is a "three way" communication between the Electronics Module, Print-head, and Wave Amplifier. Imaging data is received from either the print or scan function and isprocessed through the imaging path portion of the main board. This data then is split into twopaths. One of these paths is through the power control board to the Wave Amplifier. This datacontrols the operation of the Wave Amplifier with regard to the drive algorithm to use for drivingthe jet stacks (discussed later in the Printhead section). The second path is through a ribboncable from the main board to the Printhead control board (located on the underside of the Print-head). These two signals are interpreted by the Printhead to produce the image on the drum.Electronics Module ComponentsMain Board The main board controls the operation of all the mechanical and electricalsystems in the IOT. Through the power control and I/O boards, signalsare passed to the different gear trains, heater controls, and drive motorsand signals are received from sensors for proper operation of the IOT.The main board provides support for Ethernet and USB 2.0 external I/Ointerfaces.Image ProcessorBoardThe image processor board provides the interface between the mainboard and the scanner. The image processor board includes a completecolor image path, taking raw 24-bit RGB scanner data and creating printready CMYK or B&W binary data, 8-bit RGB data, or 8-bit grayscale data.NVRAM NVRAM, located on the main board, stores Control Panel defaults, net-work settings, IOT calibration data, copy counts, usage profile data, andthe system serial number, which is also referred to as the engine trackingnumber (ETN). When the Electronics Module is replaced, transfer theNVRAM to the replacement Electronics Module.Memory Two PC3200 compatible DDR SDRAM memory connectors are availablesupporting a minimum of 256 MB and maximum of 1 GB.
