Allen-Bradley PowerFlex 700 Repair
Flexa Systems provides component-level repair for Allen-Bradley PowerFlex 700 (20B-) AC drives with a 2-year warranty and free diagnostics. We restore discontinued drives to OEM specifications at a fraction of replacement cost, keeping your legacy automation running.
Allen-Bradley PowerFlex 700 — Overview
The Allen-Bradley PowerFlex 700 (catalog prefix 20B-) is a general-purpose AC drive introduced in the early 2000s and now discontinued. Covering 0.75–1500 HP across 200–600V three-phase applications, it remains one of the most widely deployed variable frequency drives in North American manufacturing. Common applications include conveyors, pumps, fans, mixers, and machine tools. The PowerFlex 700 offers Sensorless Vector Control (SVC), Flux Vector Control (FVC), and V/Hz control modes, with fieldbus connectivity via DPI, Modbus, DeviceNet, ControlNet, and EtherNet/IP adapters.
With new units no longer in production and used inventory scarce, component-level repair is the most cost-effective solution for maintaining these drives. Flexa Systems specializes in restoring PowerFlex 700 units to full operational status by replacing failed IGBTs, capacitors, gate drivers, control boards, and power supplies—extending service life by years while preserving your existing parameter configuration and system integration.
| Catalog Prefix | 20B- |
| Voltage Ratings | 200–240V, 380–480V, 500–600V AC (3-phase) |
| HP / kW Range | 0.75–1500 HP / 0.4–1100 kW |
| Output Frequency | 0–400 Hz |
| Control Modes | Sensorless Vector (SVC), Flux Vector (FVC), V/Hz |
| Communication | DPI, Modbus RTU, DeviceNet, ControlNet, EtherNet/IP (20-COMM-E) |
| Frame Sizes | Frames 0–10 |
| Protection Rating | IP20 / NEMA Type 1 standard |
Common PowerFlex 700 Failures We Repair
Every failure repaired at component level — root cause fixed, not just the fault code cleared.
IGBT / Power Module Failure
Shorted or open IGBTs in the inverter section trigger F12 (Hardware Overcurrent) or F70 (Power Unit) faults. Caused by prolonged overload, thermal cycling, or grid transients. We replace failed IGBT modules, test gate drivers, and verify all six output phases under load to ensure balanced operation.
DC Bus Capacitor Degradation
Electrolytic capacitors age over 10–15 years, losing capacitance and increasing ESR. Symptoms include F4 (Undervoltage), nuisance trips, and excessive ripple on the DC bus. We measure ESR and capacitance, replace out-of-spec banks, and reform new capacitors to rated voltage before reassembly.
Gate Driver Board Damage
Gate driver circuits fail due to IGBT short-circuit events, high dv/dt transients, or optocoupler degradation. Results in erratic switching, F12 faults, or inability to start. We replace damaged driver stages, verify isolation, and test gate signal timing with oscilloscope before power-on.
Control Board / CPU Faults
The 20-B2001 control board can suffer from failed EEPROM, corrupted firmware, or damaged I/O circuits. Common symptoms: F100 (Parameter Checksum), unresponsive keypad, or loss of communication. We reflow solder joints, replace memory ICs, reload firmware, and restore parameter backups when available.
Power Supply Module Failure
Internal 24V, 15V, and 5V rails power control logic and gate drivers. Failed MOSFETs, rectifiers, or regulators cause no-start conditions, blank displays, or intermittent faults. We replace discrete semiconductors, test output regulation under load, and verify ripple specs before returning the unit to service.
Fan and Thermal Management Issues
Failed cooling fans or clogged heatsinks lead to F7 (Motor Overload) or F70 (Power Unit) thermal shutdowns. While not always a board-level repair, we inspect thermal interfaces, replace failed fans, clean heatsinks, and verify thermistor calibration to prevent recurrence of temperature-related faults.
PowerFlex 700 Fault Codes Reference
Common fault codes seen on the 20B- series — what they mean and when to call for repair.
| Code | Name | Cause & Fix |
| F4 | Undervoltage | DC bus voltage below threshold; caused by weak AC supply, failed rectifier, or degraded bus capacitors—repaired by replacing rectifier diodes and capacitor banks. |
| F5 | Overvoltage | DC bus exceeds safe limit during deceleration or supply transient; fixed by repairing dynamic brake chopper, replacing brake resistor, or correcting regen configuration. |
| F7 | Motor Overload | Thermal model indicates motor overheating; verify current balance, check for mechanical binding, and confirm cooling fan operation and heatsink cleanliness. |
| F12 | Hardware Overcurrent | Instantaneous current fault detected by hardware comparator; typically indicates shorted IGBT, failed gate driver, or output ground fault—requires IGBT module and driver board repair. |
| F33 | Auto Restart Tries Exceeded | Drive attempted maximum auto-restart cycles after repeated faults; indicates underlying persistent fault (often F4, F12, or F70) requiring component-level diagnosis and repair. |
| F70 | Power Unit Fault | Internal power section fault detected—covers IGBT desaturation, gate supply loss, or thermal shutdown—repaired by replacing power modules, gate drivers, or thermal sensors. |
| F100 | Parameter Checksum Error | EEPROM or nonvolatile memory corruption detected at power-up; repaired by reflashing firmware, replacing memory IC, or restoring parameter backup if available. |
| F71 | Ground Fault | Drive detects current leakage to ground on motor cable or within power section; requires insulation testing, IGBT module inspection, and output stage repair to resolve. |
How PowerFlex 700 Repair Works
4-step process — ship us the drive, get it back repaired with a 2-year warranty
Free Diagnostic
Ship your drive. Component-level diagnostic within 24–48hrs. No charge, no obligation.
Written Quote
Detailed repair quote: what failed, what we replace, exact cost. Approve before any work.
Component Repair
Service engineers perform circuit board and component-level repair. Root cause fixed.
Load Test & Ship
Full load test under operating conditions. Ships back with 2-year warranty.
PowerFlex 700 Drives In Stock
Tested, refurbished PowerFlex 700 units available for immediate purchase or exchange. All units carry our 2-year warranty.
No PowerFlex 700 units currently in stock
We frequently add refurbished units. Contact us to check availability or request a specific catalog number.
PowerFlex 700 Repair — FAQ
Answers to the most common questions about our Allen-Bradley PowerFlex 700 (20B- series) repair service
How much does PowerFlex 700 repair cost?
PowerFlex 700 repair at Flexa Systems typically ranges from $700 to $2,200 depending on frame size and failure mode. We offer free diagnostics, no-fix no-charge guarantee, and a 2-year warranty on all repairs—saving 60–80% compared to replacement cost. Request a quote at /pages/get-quote to receive a firm price within 24 hours of evaluation.
What is the most common PowerFlex 700 failure?
IGBT and power module failures are the most common, often triggered by years of thermal cycling, grid transients, or motor ground faults. These present as F12 (Hardware Overcurrent) or F70 (Power Unit) faults. We replace failed IGBT modules, verify gate driver integrity, and test all output phases under load to ensure long-term reliability.
How long does PowerFlex 700 repair take?
Standard turnaround is 5–10 business days after receiving your unit. Rush service is available for critical applications, with 48–72 hour turnaround for an additional fee. Learn more about expedited options at /pages/rush-service.
Do you repair discontinued PowerFlex 700 drives?
Yes. The PowerFlex 700 was discontinued years ago, making component-level repair the most practical solution. We maintain an inventory of replacement IGBTs, capacitors, control boards, and power supplies specifically for legacy 20B- drives. Our repairs restore full functionality and come with a 2-year warranty, extending service life well beyond what used or refurbished units offer.
Will my PowerFlex 700 parameter settings be preserved?
Yes. Component-level repair replaces only the failed hardware—your parameter configuration, motor tuning, and communication settings remain intact in nonvolatile memory. In cases where the control board EEPROM is damaged, we can restore parameters from your backup file or help you reconfigure from documentation.
What is your warranty on PowerFlex 700 repairs?
All PowerFlex 700 repairs include a 2-year parts and labor warranty covering the repaired components. If your drive fails due to our repair within 24 months, we will re-repair or replace it at no charge. We also offer a no-fix no-charge guarantee—if we cannot restore your drive to working condition, you pay nothing. Full warranty details are available at /pages/warranty.
Ready to Get Your PowerFlex 700 Repaired?
Free diagnostic evaluation, no obligation. Most repairs returned in 5–10 business days. Rush service available in 48–72 hours for critical equipment.