Fanuc CNC Circuit Board 200 Watt Amplifier PCB A20B-2101-0020

A20B-2101-0050 | FANUC Beta-i SVM1-4i / SVM1-20i / SVM1-40i Servo Control PCB — FSSB / Dynamic Brake / A06B-6130 Series

Beta-i SVM1 — Single-Axis Economy Servo Drive

The FANUC Beta-i SVM1 series is a single-axis servo amplifier from FANUC's economy Beta-i drive line. Where the Alpha-i series SVM2 provides two servo axes in one module, the SVM1 dedicates one module to one axis — offering a simpler, more cost-effective solution for machines where single-axis drives are preferred or where individual axis replacement is more practical.

The SVM1 covers a range of output current ratings in the A06B-6130 product family:

The A20B-2101-0050 is the control PCB serving the first three variants — 4i, 20i, and 40i. The higher-current 80i uses the separate A20B-2101-0051 control PCB.

Key Specifications

A20B-2101-0050 vs A20B-2101-0051 — Control Board Selection

Both are Beta-i SVM1 control PCBs in the A20B-2101 series:

A20B-2101-0050: For SVM1-4i, SVM1-20i, SVM1-40i — current ratings up to 40A peak. The lower-current variants use power boards A20B-2101-0090 and A20B-2101-0091 with this control card.

A20B-2101-0051: For SVM1-80i and SVM1-40HVi — higher peak current and high-voltage (400–480V) variants requiring different current feedback scaling and gate drive configuration.

These two control boards are not interchangeable. Fitting A20B-2101-0051 in an SVM1-20i, or A20B-2101-0050 in an SVM1-80i, produces incorrect servo behaviour.

Application Scenarios

SVM1-40i control board fault: A Beta-i SVM1-40i servo amplifier (A06B-6130-H003) develops a servo alarm. The power board tests correctly. The A20B-2101-0050 control PCB is identified as the fault. Replacement restores servo axis function.

Multi-axis lathe servo repair: A CNC lathe uses three separate SVM1-20i drives — one per axis. One drive develops a persistent FSSB communication alarm. The A20B-2101-0050 control board on the affected drive is replaced.

FAQ

Q1: Does A20B-2101-0050 support HRV (High Response Vector) current control?

The Beta-i SVM1 series with A20B-2101-0050 supports standard HRV current control. The higher-performance HRV3 is available on the A20B-2101-0051 variant (for the SVM1-80i). For SVM1-4i, 20i, and 40i applications, the control loop bandwidth provided by A20B-2101-0050 is matched to the performance envelope of these smaller drives.

Q2: Can A20B-2101-0050 replace A20B-2101-0051 in an SVM1-80i?

No. The A20B-2101-0051 is specified for SVM1-80i — the higher-current variant requires different current feedback scaling and different gate drive interface to the larger IGBT devices. Fitting A20B-2101-0050 in an SVM1-80i will produce incorrect current regulation, likely resulting in servo alarms.

Q3: Does replacing A20B-2101-0050 require servo parameter re-entry?

No. Servo parameters (motor ID, encoder type, gains, current limits) are stored in the CNC's main parameter memory. Replacing A20B-2101-0050 does not affect stored parameters. After fitting the replacement board, the CNC re-establishes FSSB communication and applies the existing parameters to the new control PCB.

Q4: What is the power board paired with A20B-2101-0050 in each SVM1 variant?

• SVM1-4i (H001) and SVM1-20i (H002): power board A20B-2101-0091
• SVM1-40i (H003): power board A16B-3200-0512

Both the control board (A20B-2101-0050) and the power board must be intact for the drive to function. When a servo alarm traces to the drive's electronics, confirm whether the fault is in the control board or the power board before replacing only one.

Q5: Can SVM1 drives be paralleled for higher combined current?

No. FANUC SVM1 drives are designed as standalone single-axis amplifiers. Current cannot be shared between parallel SVM1 units on the same axis motor. For high-current axis requirements exceeding 40A peak (the limit of the A20B-2101-0050 range), the SVM1-80i (A20B-2101-0051) or the Alpha-i series modules are the appropriate solution.