OKI (emolevy) ML3390/91 USB => 4190

When a dot matrix printer in a busy logistics office starts producing garbled output or stops responding over USB, the culprit is often the main logic board. This genuine OKI main PCB for the ML3390 and ML3391 printers restores full control of print operations, data processing, and communication. It is the exact replacement part for OKI part number 4190, ensuring a precise fit and reliable performance.

Key specifications

• Product type: Main logic board / control board
• Compatibility: OKI ML3390, OKI ML3391 dot matrix printers
• Interface: USB (Type-B)
• Function: Controls printer operations, data processing, and communication
• Part category: Printer spare part / replacement board
• Connectivity: Internal connectors for print head, motors, control panel, and power
• Processor: Integrated microcontroller
• Memory: Integrated flash memory for firmware
• Power input: Printer dependent (internal)
• Mounting type: Screw-in
• Material: FR-4 printed circuit board
• Condition: New
• Application: Dot matrix printer maintenance & repair
• Original part number: 4190
• ESD protection: Yes
• RoHS compliance: Yes

Why choose it

This board is built to the exact specifications of the original OKI component, so you avoid the risks of generic replacements. It supports the USB interface for modern connectivity and includes integrated flash memory for firmware, ensuring your printer operates with the latest features. The FR-4 material and ESD protection enhance durability in demanding environments.

Ideal use cases

• Repairing an OKI ML3390 or ML3391 that fails to power on or communicate via USB
• Replacing a damaged main board due to electrical surge or physical impact
• Restoring a printer used for continuous multi-part forms in accounting, logistics, or manufacturing
• Maintaining a fleet of dot matrix printers where uptime is critical

Good to know

Installation requires opening the printer and disconnecting internal cables. It is recommended to be performed by a qualified technician. The board is new and RoHS compliant, meeting current environmental standards. Always power off and unplug the printer before installation.