Fanuc PC Daughter Board, A20B-2900-0155 A20B29000155 A2OB-29OO-O155

A20B-2900-0155 | FANUC Series 16/18/21 9-Inch Monochrome CRT Control Module — Option 1A / Model B & C / Replaces A02B-0130-H040

9-Inch Monochrome CRT — A Foundational Display Technology

Before colour LCD flat panels became standard on CNC machine tools, the 9-inch monochrome CRT was the dominant CNC operator interface display for more than two decades. FANUC's Series 16, 18, and 21 CNC systems in the Model B and C generations used this display type as the standard operator interface.

The 9-inch CRT presents the operator with a text-based display: programme content, axis positions, tool offsets, parameter tables, and alarm messages — all rendered in green or amber phosphor characters on a dark background. The compact 9-inch screen size fits the standard operator panel dimensions of machines from this era.

The A20B-2900-0155 is the SMD module that drives this display — generating the deflection signals, video sync pulses, and character rendering output that the 9-inch CRT requires to produce a legible image.

Key Product Information

Model B and Model C Compatibility

The A20B-2900-0155 serves two hardware generations of the Series 16/18/21:

Model B: The second hardware generation of the Series 16/18 platform. Model B introduced updated main board architecture and expanded memory capacity while maintaining the same display interface as Model A.

Model C: The final generation of the Series 16/18 before the i-generation (16i/18i). Model C further refined the hardware. The OPT 1 board interface for the 9-inch CRT module remained consistent, allowing the A20B-2900-0155 to serve across both B and C generation hardware.

For the Series 21, the same display interface applies — the 9-inch monochrome CRT was used across the 16/18/21 family in these hardware generations.

Application Scenarios

CNC display failure on 16-B control: A FANUC Series 16-B CNC's 9-inch monochrome display goes blank. The CNC continues running normally — no axis or programme alarms — confirming the fault is in the display section. The A20B-2900-0155 module is identified as the failed component on the OPT 1 board. Replacement restores the operator display.

A02B-0130-H040 replacement: A Series 18-C CNC has an A02B-0130-H040 CRT board that begins showing display irregularities. Rather than seeking the increasingly scarce original board, the A20B-2900-0155 is fitted as the direct replacement. The display operates normally with no configuration changes required.

Series 21-C retrofit: A Series 21-C CNC undergoes a control unit service. The CRT control module is replaced proactively with the A20B-2900-0155 as part of a board refresh programme.

FAQ

Q1: What is the difference between the A20B-2900-0155 and the A20B-2902-0270 in the same CRT module family?

These two modules serve fundamentally different display configurations:

• A20B-2900-0155: 9-inch monochrome CRT, for Series 16/18/21 Model B/C — the simpler, earlier display
• A20B-2902-0270: 14-inch colour CRT, for Series 16/18 Model B — the larger, colour display option

They are not interchangeable. Selection depends on the physical monitor size and type installed on the machine.

Q2: Can the A20B-2900-0155 drive an LCD monitor as a direct replacement for the 9-inch CRT?

No. The A20B-2900-0155 generates signals compatible with CRT deflection and sync requirements — it does not output standard VGA or digital LCD signals. Replacing the CRT with an LCD requires either a CRT-to-LCD video converter or a complete display interface retrofit. The A20B-2900-0155 itself must be present and functional to drive a CRT monitor; it is not compatible with direct LCD connection.

Q3: What is "Option 1A" and how does it differ from "Option 1"?

"Option 1A" refers to the specific configuration of the Option 1 board that accepts the A20B-2900-0155 module. The "A" suffix distinguishes this from other Option 1 board variants that accept different display modules (such as Option 1B for colour displays or different-size modules). When ordering the A20B-2900-0155, confirm the CNC's Option 1 board variant matches the "1A" designation.

Q4: Does replacing A20B-2900-0155 require CNC parameter changes?

No. The CRT control module is a display hardware component and does not carry CNC parameters. After fitting the replacement A20B-2900-0155 on the OPT 1 board and powering the system, the display should restore normal operation immediately. If the display shows incorrect character sizing or sync issues, the CNC's display-related parameters (if any exist for the specific system configuration) should be verified, but parameter re-entry is not normally required for a like-for-like module replacement.

Q5: How does the A20B-2900-0155 compare in availability to the older A02B-0130-H040 it replaces?

The A20B-2900-0155 was designed specifically to extend the service life of systems that were previously limited to the A02B-0130-H040 board. As the A02B-0130-H040 has become increasingly difficult to source due to its age, the A20B-2900-0155 provides a current-production or widely-stocked alternative that serves the same function on the same hardware. Sourcing the A20B-2900-0155 is typically more straightforward than finding a reliable A02B-0130-H040.