C594 SUB-B ASSY BOARD - 2093628

2093628 – Sub-B board (C594 Sub-B Assy Board) – Epson Stylus Pro

The sub board (C594 Sub-B Assy Board, 2093628) is fitted to Epson printers. It ensures the electronic control of a machine sub-system and passes the signals to the main board.

In the Epson Stylus Pro 7400/7800/9400/9800 service manual, the "C594 SUB-B Board" is the "Relay Board 2" of the right ink compartment: connected to the main board by a 26-pin flat cable (Main CN21), it relays the right cartridge lever sensor, the four CSIC relays of the right cartridges, the maintenance tank, the two paper thickness sensors and the pump phase sensor.

Technical specifications

• OEM reference: 2093628
• Manufacturer: Epson
• Part type: Sub-B board (PCB)
• Manufacturer designation: "BOARD ASSY., SUB; B"; schematic name "C594 SUB-B Board" ("Relay Board 2" in the service manual)
• Connectors: CN1: 26-pin FFC flat cable to the main board (CN21); CN5: 2 pin ("I/C Lever Sensor R"); CN6, CN7, CN8, CN9: 7 pin (CSIC relays R1 to R4); CN10: 7 pin (maintenance tank); CN12: 3 pin ("P Thick1 Sensor"); CN13: 3 pin ("P Thick2 Sensor"); CN20: 3 pin ("Pump Phase Sensor")
• Location: Right side of the printer, behind the "R Side Cover Assy"; fixed by 4 M3×8 pan head screws
• Adjustment after replacement: Service manual, required adjustments table: "Colorimetric Calibration" (Color ID) after replacing a Relay Board
• Note: The service manual does not give the part code: the association 2093628 ↔ "C594 SUB-B" is that of the sheet name and of sellers. The manual covers the 7400/9400 and 7800/9800, noting connector differences between the two variants. The Stylus Pro 7500 and 9500 listed above belong to an earlier generation (non-C594 boards): no source cites them for 2093628, check before ordering.
• Shipping: Shipped ready to install

Compatibility & use

• Epson STYLUS PRO 74xx
• Epson STYLUS PRO 75xx
• Epson STYLUS PRO 78xx
• Epson STYLUS PRO 94xx
• Epson STYLUS PRO 95xx
• Epson STYLUS PRO 98xx
• The service manual gives two connector assignment tables (7400/9400 variant and 7800/9800 variant): rely on the markings silk-screened on the board before reconnecting.
• For error "00010020", the manufacturer specifies replacement in order: CSIC contact, cartridge, "Holder Assy IC" right/left, then Sub Board B/C, then the main board.

Function

• Relay from the right ink compartment to the main board (26-pin flat cable on Main CN21)
• Connects the right lever sensor, the 4 CSIC relays of cartridges R1 to R4, the maintenance tank, the paper thickness sensors "P Thick1"/"P Thick2" and the pump phase sensor
• Ensures the electronic control of a sub-system
• Passes the signals to the main board
• Acts as an interface between the firmware and the hardware

Signs of wear

• "SERVICE CALL 00010020" (CSIC reading/writing error): unable to read or write the cartridge chips — the only error in the manual explicitly citing replacement of the Sub Board B/C
• Depending on the sensors it relays, a failure can result in unrecognised right cartridges, an undetected right ink lever, an undetected maintenance tank or an inconsistent paper thickness reading (not documented as codes specific to this board)
• Sub-system not driven
• Electronic errors
• Loss of internal communication
• Erratic behaviour or machine stops

Replacing this part restores the machine to proper working order.

Related parts

• 2093630 — "BOARD ASSY., SUB; C" (C594 SUB-C, Relay Board 3, symmetrical board on the left side)
• 2093626 — "BOARD ASSY., SUB" (C594 SUB Board, Relay Board 1, on the carriage)
• Holder Assy IC Right — CSIC relays R1 to R4 of the right cartridges, connected on CN6 to CN9

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