Okuma 1911-2861-0236049 Graphic Card Circuit Board for CNC Control Systems

The Okuma 1911-2861-0236049 is a graphic card module (circuit board) used in Okuma CNC machine control systems, particularly in the OSP (Okuma Sampling Path) series such as OSP-P200, OSP-P300, and older models. This board generates the video output for the operator’s CRT or LCD display, rendering toolpath graphics, machine status screens, and PLC ladder diagrams. It interfaces with the main CNC processor and the PLC (Programmable Logic Controller) section of the machine. This replacement part is critical for maintaining legacy Okuma machining centers, lathes, and grinders.

Technical Specifications

The board is a standard half-length ISA or PCI form factor (depending on the OSP generation). It features a graphics processor (likely an S3 or Chips & Technologies chip) with 2 MB of video RAM (expandable to 4 MB). Output resolution is typically 640 x 480 (VGA) or 800 x 600 (SVGA) at 60 Hz. The board provides a 15-pin D-sub VGA connector and may also include a separate output for the machine’s built-in CRT. It operates on +5 VDC and ±12 VDC from the backplane, consuming approximately 10 W. The board includes a BIOS ROM specific to Okuma.

Function in Okuma CNC Systems

In the Okuma OSP architecture, the graphic card is responsible for rendering all visual elements on the operator panel: the NC program display, tool path simulation, machine diagnostics, and PLC ladder monitoring. It works in conjunction with the main CPU board and the PLC I/O boards. The card receives drawing commands from the CNC software and outputs a video signal to the monitor. If the graphic card fails, the machine may still run (if the operator can operate blindly), but the display will be blank or garbled, making normal operation impossible.

Compatibility and Identification

The exact part number 1911-2861-0236049 is specific to a particular revision of the OSP control. It is often found in machines manufactured between 2005 and 2012. The board may also be labeled with Okuma’s internal code “1911-2861” and a suffix. Before ordering, verify the original board’s part number and the machine’s OSP version. Some cross-compatible part numbers include 1911-2861-0236050 (later revision) and 1911-2861-0236048 (earlier). The board may require a firmware update to work with newer OSP software.

Installation Notes

Replacement of the graphic card must be performed by qualified service personnel. Power down the CNC control cabinet and discharge static electricity. The board is inserted into an ISA/PCI slot on the main backplane. Ensure that any jumpers on the new board match the old board (especially for IRQ and memory address settings). After installation, the CNC may need to have its video driver re-initialized (via the OSP maintenance menu). In some cases, the CMOS settings on the main CPU board must be reconfigured to recognize the new card.

Failure Symptoms and Diagnostics

Common signs of a failing graphic card: no display (black screen) but machine boots, distorted or flickering screen, vertical lines, incorrect colors (if color display), or the monitor showing “no signal”. The machine may still respond to key presses if the operator knows the menu structure. To diagnose, try the board in a known-working slot or test the monitor with another source. Okuma’s diagnostic software (if available) can perform a video RAM test.

Environmental and Reliability

The board is designed for industrial environments with temperature range 0°C to 55°C and humidity 10% to 90% non-condensing. It uses solid-state capacitors for long life. The MTBF is estimated at 100,000 hours. However, due to age, electrolytic capacitors may degrade; re-capping is a possible repair. The board is not conformal coated; avoid exposure to dust and moisture.

Ordering and Availability

Okuma part number: 1911-2861-0236049. This board is considered an obsolete spare part; however, Okuma America Corporation may still have limited stock through their spare parts department. Alternatively, third-party repair services offer exchange or repair of these boards. When ordering, provide the machine serial number and OSP version. A functional test after replacement is mandatory. This board is not user-serviceable; any repair should be done by an electronics specialist.

Important Notes for Legacy Systems

As Okuma has moved to newer OSP controls (OSP-500, OSP-700, etc.), this graphic card is no longer in production. For long-term support, consider a CNC retrofit or a modern PC-based graphics emulator. However, for many shops, keeping the original board functional is the most economical path. This documentation is provided for reference only; always consult the Okuma maintenance manual for your specific machine model.