What the A.410 alarm means

The main-circuit DC bus voltage dropped below the limit (about DC 170 V); the drive cannot hold the axes and shuts down the servo. This fault appears in a large share of our Yaskawa DX100 / DX200 / YRC1000 service tickets, and the first round of on-site checks usually finds the source.

Most common causes

  • Incoming AC voltage low or a momentary power dip
  • Blown fuse or open input wiring
  • Inrush-current limiting resistor open from frequent power cycling
  • Loose main-circuit terminals
  • Motor cable short dragging the bus down
Field note: Most of the time the problem is the first item on the list, so ruling it out saves you half the time.

Step-by-step field fix

  1. Measure the incoming AC voltage at the cabinet under load
  2. Check input fuses and phase condition
  3. Tighten all main-circuit terminals
  4. Reduce power ON/OFF cycling frequency (max 5 times/minute recommended)
  5. Inspect the motor power cable for shorts; replace the SERVOPACK only after supply is stable
Safety first: For YASKAWA a-410, this alarm family involves the DC bus, which sits at several hundred volts and stays charged for minutes after power-off - touching terminals is a shock hazard. On site you may not carry out the first step yourself: Measure the incoming AC voltage at the cabinet under load. Beyond that it is the DC bus and power stage work - leave it to a professional. On YASKAWA a-410: checking incoming voltage at the disconnect and looking at breakers and fuses is fine to do yourself; opening the cabinet to touch bus terminals or pulling power modules needs a qualified electrician.

How we diagnose drive alarms on site

YASKAWA a-410 belongs to the drive & power stage family. On YASKAWA a-410 the failing stage is Yaskawa Sigma-series servo drives (servo packs) assigned per axis in the cabinet on the DX100 / DX200 / YRC1000 / YRC1000micro - the fault sits on the energy chain: mains input, rectification, DC bus, braking resistor, inverter power devices and the drive board. We start reading YASKAWA a-410 at the pendant alarm list (A / E / 4xxx segments) together with the servo drive's digit display.

The chain involved in YASKAWA a-410 runs: three-phase mains -> rectifier -> DC bus (bus capacitors) -> brake chopper / braking resistor -> inverter (IGBT) -> motor.

When YASKAWA a-410 fires, the site usually reports Incoming AC voltage low or a momentary power dip first, but the real cause is often cooling: More than half of power-stage alarms are not a dead device but a device cooked by failed cooling. A stopped cabinet fan, a packed filter mat or a dusted air duct keeps IGBT junction temperature high: intermittent over-temperature first, hard fault days later. On these alarms we open the power module and look for cracked thermal paste and felted dust in the duct, then measure phase-to-phase output and insulation to frame. Swapping the module without cleaning the duct just buys the same failure again.

Field notes on this page cover YASKAWA a-410 (Undervoltage — Main Circuit DC Voltage Too Low); written by the Henghuan repair team, updated 2026-10-01.

Real Field Case

Machine: Yaskawa MH12 (DX200) (2016)

Symptom: A Yaskawa MH12 raised A.410 (main-circuit undervoltage).

What we did: We measured the three-phase input and found one phase low, traced the shop supply and wiring, and restored balanced supply.

Result: The alarm cleared once supply was restored and we advised adding voltage monitoring; about 2.5 hours.

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Related Drive & Power Stage alarms

A.100 — Overcurrent or Heat Sink Overheated (SERVOPACK) A.320 — Regenerative Overload A.400 — Overvoltage — Main Circuit DC Voltage Too High A.710 — Overload — High Load (Stall-level Torque) A.720 — Overload — Low Load (Continuous Over-torque) A.7A0 — Heat Sink Overheated (>100 degC)
Same family: this code belongs to the Drive & power stage alarms family - the page collects all Drive & power stage-family codes we have handled, with the common inspection order and spares.
Other brands: we also keep field-fix libraries for Universal Robots · Kawasaki · Staubli and more — see the complete alarm code hub.

Frequently asked questions

QWhat does the YASKAWA a-410 alarm mean?

The main-circuit DC bus voltage dropped below the limit (about DC 170 V); the drive cannot hold the axes and shuts down the servo. This fault appears in a large share of our Yaskawa DX100 / DX200 / YRC1000 service tickets, and the first round of on-site checks usually finds the source. YASKAWA a-410 sits in the drive & power stage family; on our work orders the highest-frequency trigger for this code is "Incoming AC voltage low or a momentary power dip".

QCan I clear a YASKAWA a-410 alarm myself?

Whether YASKAWA a-410 clears on its own depends on the outcome of "Measure the incoming AC voltage at the cabinet under load". Finish the flow with "Inspect the motor power cable for shorts; replace the SERVOPACK only after supply is stable" to confirm YASKAWA a-410 - do not skip it. If that step is clean, the second most frequent cause on YASKAWA a-410 is "Blown fuse or open input wiring". If YASKAWA a-410 returns after two clears, or the checks point at Incoming AC voltage low or a momentary power dip, stop the cell and call a professional robot repair engineer.

QFor drive/power alarms like YASKAWA a-410, what spares do you bring on site?

The commonest causes we see on YASKAWA a-410 are "Incoming AC voltage low or a momentary power dip, Blown fuse or open input wiring, Inrush-current limiting resistor open from frequent power cycling", so we stock the van against those. For YASKAWA a-410 specifically, we stock the van along the energy chain: braking resistors, bus capacitors, input fuses, drive-board supply parts and the common power modules for the brand. For YASKAWA a-410, drive alarms usually stop the whole line, so they sit at the front of our dispatch queue. Before we roll, tell us what YASKAWA a-410 shows on the pendant alarm list (A / E / 4xxx segments) together with the servo drive's digit display and what the machine was doing - phone or video triage is free.

This page on YASKAWA a-410 is based on the field experience of the Henghuan Robotics repair team. Alarm explanations are our own summary for troubleshooting reference and may differ across controller and software versions — if unsure, verify against Yaskawa documentation or reach out to us. Henghuan is an independent service provider with no affiliation or endorsement by Yaskawa.