Allen-Bradley
Allen-Bradley Servo Drive Repair (Ultra 3000, Ultra 100/200, Kinetix evaluated) — Mail-In
Component-level repair for Allen-Bradley/Rockwell servo drives. Ultra 3000 (2098) and Ultra 100/200 are fully bench-testable and repair well. Kinetix 6000-class shared-bus modules are accepted for evaluation with honest limits disclosed up front.
Coverage: Ultra 3000 (2098-DSD) · Ultra 100 / 200 · Kinetix 300/350 · Kinetix 6000 (evaluation — see note)
✓Fixed — or it's free
Unrepairable units are refunded; evaluations cost $0
✓24-month warranty
Every repair covered, parts and labor
✓3–5 business days bench time
Rush (1–2 day) and emergency service available
✓Program preserved
Your application and settings stay in the unit
Symptoms this repair fixes
- ✓Drive faults: overcurrent, bus over/undervoltage
- ✓Dead drive — no display or link
- ✓Trips at enable
- ✓Feedback faults traced to the drive
Honest limits
- ✕Kinetix 6000 shared-DC-bus modules cannot be fully load-validated outside a multi-axis rack — we disclose exactly what our bench can and cannot prove before you approve anything
What you get
- ▸Free bench evaluation and firm quote
- ▸IGBT and power-stage replacement
- ▸Control supply, encoder, and SERCOS interface repair
- ▸Full recap as standard
- ▸24-month warranty
Common part numbers we see
Part-number pages for this service
How Allen-Bradley Servo Drive units actually fail
Most units we receive fail in one of a handful of well-understood ways. Here is what each fault looks like from the machine, what is happening electronically, and what we do about it at the bench.
Power stage failure
- What you see
- Overcurrent or ground faults, or a drive that trips as soon as it is enabled.
- Why it happens
- Output power device failure, typically caused by a shorted motor or a damaged motor cable rather than arising on its own.
- What we do
- The power stage is tested cold device by device and repaired, gate drive verified, and the drive proven under load.
Bus capacitor and pre-charge faults
- What you see
- Undervoltage alarms, or a drive that will not come up cleanly on power-on.
- Why it happens
- Aged bus capacitors, or a failed inrush limiting circuit that prevents the bus charging correctly. The second is much less serious than it appears.
- What we do
- The bus and pre-charge path are both assessed, the actual fault repaired, and correct power-up verified.
Feedback interface damage
- What you see
- Feedback alarms, position loss, or unstable axis behaviour.
- Why it happens
- Damage to feedback circuitry, frequently traced back to a cable fault at the machine.
- What we do
- Feedback circuitry is repaired and stable position control confirmed under load.
Cooling failure
- What you see
- Thermal alarms after sustained running.
- Why it happens
- Failed cooling fans or a heatsink obstructed by plant dust.
- What we do
- Cooling is restored and thermal behaviour verified while running under load.
What happens on the bench
The same sequence on every 6-stage repair, so nothing gets skipped because a fault looked obvious.
- 1
Safe intake and bus discharge
Drives arrive holding charge in the DC bus capacitors. The unit is discharged and verified at zero before anything is opened — this is a genuine hazard on any drive with a large capacitor bank, not a formality.
- 2
Power stage integrity check
The IGBT or power module is checked device by device for shorted and open junctions before power is ever applied. Energising a drive with a shorted power module simply destroys more of it, so this is done cold, first, every time.
- 3
DC bus and pre-charge inspection
Bus capacitors are assessed for capacitance loss and elevated ESR, and the soft-charge circuit — inrush resistor and its bypass relay or contactor — is checked. A drive that reports undervoltage or trips on power-up very often has a failed pre-charge path rather than a failed power stage.
- 4
Gate drive and feedback circuitry
Gate driver stages and their isolation are tested, because a partially degraded driver produces asymmetric switching that reads as an intermittent overcurrent fault under load and as a perfectly healthy drive at idle. Encoder and feedback interfaces are checked for the damage a shorted motor cable pushes back into the drive.
- 5
Thermal path and cooling
Fans, heatsink airflow and thermal interfaces are serviced. A large share of "failed" drives are thermal alarms caused by a seized fan or a heatsink packed with production dust.
- 6
Powered test under load
The repaired drive is brought up through a controlled power-on and run against a load so the power stage, current regulation and thermal behaviour are proven in operation — not merely confirmed to power up without alarming.
Check these before you ship
Some of these will tell you the unit is fine and the fault is elsewhere. We would rather you find that out now than pay to ship a good unit.
- □Megger the motor and its cable before condemning the drive. A shorted winding or a cable chafed against the machine frame will destroy a replacement drive exactly as fast as it destroyed the first one.
- □Record the alarm code and what the machine was doing when it tripped — during acceleration, at speed, on a hard stop, or only when warm. That distinction separates a power-stage fault from a thermal or feedback fault.
- □Check whether the cooling fan still spins freely and whether the heatsink is clogged. If the only fault is a thermal trip, cleaning and a fan may fix it on your bench.
- □Confirm incoming line voltage and phase balance. Repeated drive failures on one axis are often a supply or wiring problem the drive is simply reporting.
- □Note your parameter set if you have it recorded. Drive parameters normally live in the CNC or the drive's protected storage and our physical repairs do not touch them, but a record is worth having.
Repair or replace?
Servo and spindle drives are where repair economics are most favourable: the hardware is expensive, frequently obsolete, and often tied to a specific machine and parameter set. New replacements for older platforms are commonly quoted at multi-week lead times when they are available at all, and a like-for-like replacement still has to be parameterised and commissioned against the machine. Because a drive failure usually stops the machine outright, the number that matters is rarely the invoice — it is how many production days pass before the axis turns again.
What to ship
- ▸The drive module only
- ▸Fault code + system details
Full packing guidance: mail-in instructions.
Ship your unit to
USPS
Control Board Lab
PO Box 120241
Arlington, TX 76012
UPS / FedEx
Control Board Lab
1009 Oakwood Ln # 120241
Arlington, TX 76012
Write your RMA number on the outside of the box and include it on a note inside. Units over 50 lb (large VFDs, spindle drives, industrial PCs in enclosures) ship by freight — contact us before ordering and we will arrange dock-to-dock shipping.
Frequently asked questions
Why is Kinetix 6000 "evaluation-limited"?
Kinetix 6000 axis modules share a DC bus with the rack's power module — a full load validation requires a matching multi-axis rig. We repair the common failures and verify everything our bench can prove, and we tell you exactly where that boundary is before you approve a repair. If that isn't enough certainty for your application, we'll say so plainly rather than oversell the test.
Start with a free evaluation
Ship it in, get a firm quote, approve before any work — pay nothing if it can't be repaired.
The Fixed-or-Free Guarantee: if we can't repair it, you don't pay for the repair.
Call (817) 799-7332 · 📱 Text us a photo of your unit · Email repairs@controlboardlab.com