Allen-Bradley
Allen-Bradley PowerFlex VFD Repair (525 / 40 / 70 / 700 up to 25 HP) — Mail-In
Component-level repair for Allen-Bradley PowerFlex variable frequency drives up to 25 HP: 525, 523, 40, 4M, 70, and 700 series. IGBT modules and bus capacitors are the classic failures. Free evaluation, typical repairs $350–$900.
Coverage: PowerFlex 523 / 525 · PowerFlex 4 / 40 / 4M · PowerFlex 70 / 700 — up to 25 HP
✓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
- ✓F004 / F005 / F012 class faults (undervolt, overvolt, overcurrent)
- ✓Dead drive — no display
- ✓Trips breaker at power-up
- ✓Output phase loss / motor won't turn
- ✓Dead keypad or display
Honest limits
- ✕Drives over 25 HP (declined at launch — full load validation requires capacity we don't claim yet)
- ✕Motor-side faults (identified at evaluation)
What you get
- ▸Free evaluation and firm quote
- ▸IGBT module replacement with new components
- ▸DC bus capacitor replacement
- ▸Precharge, control board, and keypad repair
- ▸Powered functional test with motor load appropriate to frame size
- ▸24-month warranty
Common catalog numbers we see
Part-number pages for this service
How PowerFlex VFD 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.
Output power stage failure
- What you see
- Ground fault or overcurrent trips, or a drive that faults the moment it is started.
- Why it happens
- The output IGBT stage fails, most often because of a motor insulation failure or a damaged motor cable. Long motor leads and reflected-wave stress make this more likely on some installations than others.
- What we do
- The output stage is tested cold, failed devices replaced, gate drive verified, and the drive run and its output proven before return.
DC bus capacitor degradation
- What you see
- Bus or undervoltage faults, or trips during acceleration only.
- Why it happens
- Capacitance loss and rising ESR with age. Drives that have sat unpowered in stores are a special case, because the oxide layer degrades without applied voltage and the drive can fail on first energisation.
- What we do
- Bus capacitors are assessed and replaced, with storage history taken into account, and bus behaviour verified under load.
Pre-charge circuit failure
- What you see
- The drive trips immediately on power-up or reports undervoltage as soon as it is loaded.
- Why it happens
- The inrush limiting resistor and its bypass relay wear out. This looks like a serious bus or power fault and is usually a much smaller repair.
- What we do
- The pre-charge path is tested and repaired and correct power-up behaviour verified.
Cooling and overtemperature
- What you see
- Overtemperature faults, typically after the drive has been running in a warm panel.
- Why it happens
- Failed cooling fans and heatsinks packed with dust — extremely common and often the entire fault.
- What we do
- Cooling is restored and thermal performance verified under load. If cooling was the whole problem, the evaluation will say so.
What happens on the bench
The same sequence on every 5-stage repair, so nothing gets skipped because a fault looked obvious.
- 1
Discharge and inspection
The bus is discharged and verified at zero, then the drive is inspected for the physical evidence that dates a failure — vented capacitors, heat-darkened board, corrosion from a damp or chemically aggressive environment, and dust loading in the heatsink.
- 2
Power stage and rectifier test
The input rectifier and the output IGBT stage are tested cold for shorted or open devices. Ground-fault and overcurrent trips are traced to the specific failed device rather than treated as a single generic "output fault".
- 3
DC bus capacitor assessment
Bus capacitors are measured for capacitance and ESR. Drives that have sat unpowered in stores for years are a special case: the oxide layer in an electrolytic capacitor degrades without voltage, and a drive that has been on a shelf can fail immediately on first energisation.
- 4
Pre-charge and control power
The inrush limiting circuit and its bypass, plus the control-power supply, are checked. A drive that trips instantly on power-up or reports undervoltage under load frequently has a failed pre-charge resistor or bypass relay, which is a far smaller repair than the symptom suggests.
- 5
Repair, then run test
After board-level repair the drive is run and its output verified, with the thermal path cleaned and cooling restored, so it returns proven under power rather than merely powering up.
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.
- □Test the motor and motor cable first. An insulation fault downstream is the most common reason a drive fails again shortly after being replaced.
- □Write down the exact fault code and whether it trips on power-up, on start, during acceleration, or only under load once warm — each points somewhere different.
- □Check the heatsink and fan. Overtemperature faults on a dust-packed drive in a hot panel are often a cleaning job, not a repair job.
- □Confirm all three input phases are present and balanced. Input phase loss both causes drive faults and shortens bus capacitor life.
- □If the drive has been in storage for years, say so — it changes how we approach the capacitor bank.
Repair or replace?
Drives sit in the middle of the repair-versus-replace decision, and we will tell you when replacement is the better call. Repair wins decisively when the drive is obsolete, when it is one of many identical units you intend to keep as a maintainable fleet, or when a replacement means re-engineering mounting, wiring or parameters. A current-generation general-purpose drive in a small frame size can be cheap enough new that repair is not worth it — and if that is your situation, we would rather say so during the free evaluation than sell you a repair.
What to ship
- ▸The drive only — no cables
- ▸Fault code + HP/voltage + what tripped it
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
A new PowerFlex 525 is only a few hundred dollars more than a repair — why repair?
Sometimes replacement IS the right call, and we'll tell you when it is. Repair wins when lead time matters (drives can be weeks out), when your drive carries a configured parameter set your team doesn't want to rebuild, or on the larger frames where new pricing jumps into four figures.
Why only up to 25 HP?
Above ~25 HP, honestly validating a repair needs three-phase load-bank capacity. We publish the boundary instead of quietly under-testing big drives. As the lab's test capacity grows, the ceiling will move — check back or ask.
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