A20B-8101-0191 Fanuc PCB Board A20B81010191 A2OB-8IOI-OI9I

FANUC A20B-8101-0191 Power Supply PCB

Overview

The A20B-8101-0191 is a power supply PCB in the A20B-8101 family. Parts and service listings describe it as a power supply unit and also as a DC-DC converter for compatible 16i, 18i, and 21i control systems.

One service listing identifies it more specifically as a model B bolt-on DC-DC converter attaching to the main board, which places it clearly in the control power section rather than in the display, I/O, or servo-amplifier categories.

This board is important because it supports the internal power-conversion structure of the control.

In practical maintenance work, a board in this position is matched by exact installed role, since the internal power architecture of the controller depends on the original converter and power-board layout. 

Keeping the same model helps preserve that original hardware arrangement.

Technical Data

Applications

This board is suitable for installed FANUC control systems where the original hardware already uses the A20B-8101-0191 power-board position, especially in 16i, 18i, and 21i environments.

It is particularly relevant in control repair, board replacement, and exchange-based spare support where the original internal power structure must remain unchanged.

Replacement Guidance

Before ordering, confirm the installed board code, verify that the machine uses the same power supply / DC-DC converter position, and check that the control family matches the 16i / 18i / 21i application context.

On internal power boards, exact model continuity is one of the most important replacement checks because the board is tied directly to the controller’s internal power structure.

FAQ

Q1: What kind of board is A20B-8101-0191?
It is a power supply PCB and DC-DC converter board used in FANUC control hardware. Listings identify it as both a power supply unit and a converter module, which places it in the internal power-conversion section rather than in the display, memory, or I/O side of the controller.

Q2: Why is the DC-DC converter description important?
Because that description identifies the board by function, not just by part number. A board described as a DC-DC converter is part of the control’s internal power-conditioning path, so it should be replaced with the same functionally matched model to maintain the original power structure of the system.

Q3: Which controls is this board commonly associated with?
Service listings connect it with 16i, 18i, and 21i control systems, and one listing describes it as a model B bolt-on DC-DC converter attached to the main board in those control families. That gives it a clear installed-base context for repair and replacement work.

Q4: Is this a main board or a support board?
It is a support board in the power section, not the system main board. Its job is tied to internal power supply and conversion for the control system, which is why it must be matched by exact installed function rather than by appearance alone.

Q5: What should be checked before buying?
Check the installed board code, confirm the control family is 16i, 18i, or 21i, and verify that the original board is A20B-8101-0191 in the power-supply / DC-DC converter position.

Those are the main compatibility points for correct replacement.