A20B-8100-0720 Fanuc PCB Board A20B81000720 A2OB-8IOO-O72O

FANUC A20B-8100-0720 Power Supply PCB

Overview

The A20B-8100-0720 is a power supply PCB in the A20B-8100 family. It is described as a power supply PCB module and also as a DC-DC converter used with FANUC i-series controls, including references to 16i-B, 18i-B, 21i-B, and 0i-B control environments.

One description also identifies it as a converter mounted onto the main board, which places it in the internal control power section rather than in the display, I/O, or servo amplifier sections.

This board plays a support role that is highly important inside the controller: it stabilizes or distributes internal power where the rest of the control hardware depends on it.

In practice, power boards are selected by exact board code and exact installed position because even a small mismatch can affect startup stability, board-to-board supply distribution, and long-term controller reliability.

Because it appears in both stock and refurbishment channels, the model is clearly a common service item for installed i-series systems that remain active in the field.

Technical Data

Applications

This board is suitable for installed FANUC i-series CNC controls where the original hardware already uses the A20B-8100-0720 power-board position.

It is especially relevant in controller repair, power-board replacement, and preventive maintenance where the machine remains sound overall but internal supply stability must be restored. It is also useful in exchange-based service support for older i-series controls that remain in operation.

Replacement Guidance

Before ordering, verify the board code directly on the installed hardware and confirm that the controller uses the same power supply / DC-DC converter arrangement. It is also worth checking the control family, because this model is tied to specific i-series platforms.

On internal power boards, exact installed-position matching matters more than visual similarity because the board serves the controller’s supply architecture rather than a simple peripheral function.

FAQ

Q1: What kind of board is A20B-8100-0720?
It is a power supply PCB and DC-DC converter board used inside FANUC i-series control hardware. Its role is tied to internal power handling and stable board-level supply distribution, not to display driving, network communication, or servo amplifier logic.

Q2: Why is the DC-DC converter description important?
Because that description defines the board by function. A DC-DC converter board supports the controller’s internal power architecture, so replacing it with the correct model helps preserve startup behavior, stable operation, and compatibility with the installed control platform.

Q3: Which controls is this board commonly associated with?
It is associated with 16i-B, 18i-B, 21i-B, and 0i-B control families. That gives it a clear installed-base role in FANUC i-series systems and makes it particularly relevant for long-term support of those controls.

Q4: Is this a main board?
No. It is a support board in the power section, not the system motherboard. The main board handles the broader control platform, while this board supports the internal supply side of that platform.

Q5: What should be checked before buying?
Check the installed board label, confirm the control family, and verify that the existing board really is A20B-8100-0720 in the power-supply / DC-DC converter position.

Since power boards can appear physically similar, verifying the actual board code on the machine is the safest way to avoid mismatch.