Power stage rebuild
IGBT modules, gate drivers, and DC bus capacitors replaced on Fanuc alpha / beta, Mitsubishi MR-J, and Yaskawa Sigma amplifiers.
CNC Machine Servo Drive Repair
Independent third-party component-level repair of servo drives and amplifiers on CNC machining centers, lathes, grinders, and EDM equipment. Fanuc alpha and beta amplifiers, Siemens SINAMICS, Mitsubishi MR-J, Yaskawa Sigma drives.
Where These Drives Sit
Four CNC application contexts
Servo drives end up at the bench from a wide spread of CNC machine types. Below are the four common contexts.
01
Machining centers
Vertical and horizontal mills, 5-axis machining centers, and gantry mills. X / Y / Z and rotary-axis servo drives.
02
CNC lathes & turning
Two-axis turning centers, multi-spindle Swiss-type lathes, and live-tool lathes. Spindle and X / Z amplifier coverage.
03
Grinders
Surface grinders, cylindrical grinders, and centerless grinders with closed-loop position drives on slide and wheel-head axes.
04
EDM equipment
Sinker and wire EDM machines with axis servo drives running close-tolerance positioning duty.
What NC Servo Does
Component-level repair on CNC drives
Each unit is opened, inspected, and rebuilt at the component level. Failed parts come from inventory or off donor units. Bench verification before ship.
Control board work
Component-level board repair, firmware checks, and feedback-channel verification on encoder interfaces and serial loops.
Cooling & power supply
Cooling-fan replacement, power-supply rebuild, and thermal-path inspection on cabinet-mounted hardware.
Bench testing
Electronic test setup with dummy load and feedback emulation. Performance check before ship.
Donor parts service
19,000+ unit in-house pool. Aftermarket parts and donor units for legacy CNC amplifier hardware.
Repair scope
Hardware repair only. CNC parameters, ladder logic, and machine commissioning stay with the customer or integrator.
Brands
CNC drive brands serviced
Top brands seen on CNC servo drives. Click through for the dedicated brand page.
Common Faults
What usually shows up on CNC drives
CNC servo drives run continuous duty in shop-floor cabinets. Failures fall into four categories.
| Power stage | Failed IGBT modules, blown DC bus capacitors, and gate-driver damage. Often follows a power-event or cooling-fan failure on the cabinet. |
|---|---|
| Cooling & thermal | Cooling-fan failure, heatsink contamination, and thermal-stress damage on the power module after years of shop-air exposure. |
| Control electronics | Encoder-interface damage, communication-module failure, and capacitor aging on the control board. |
| Cabling and connectors | Damaged feedback cables, encoder connector wear, and contamination on encoder pins. |
Workflow
From part number to ship-back
Same four-step path through the shop whether the drive came off a Mazak machining center or a Fanuc-controlled grinder.
- 01
Get in touch
Call or email with the part number, machine context, and a photo of the nameplate if it helps.
- 02
Bench review
Tech inspects the drive, runs it on the test bench, and confirms what failed.
- 03
Cost & approval
We call back with the cost and a rough turnaround. Nothing is started without your sign-off.
- 04
Repair, test, ship
Failed components replaced from inventory or off donors, drive verified on the bench, and shipped back.
FAQ
Common questions about CNC drive repair
Application-specific questions. For brand-specific FAQs, see the dedicated brand page above.
What types of CNC servo drives do you repair?
Servo drives and amplifiers from Fanuc (alpha / beta series), Siemens (SINAMICS S120 and 611D), Mitsubishi (MR-J series), Yaskawa (Sigma series), Allen-Bradley (Kinetix and Ultra), Indramat (DDS, EcoDrive), Kollmorgen, and Baldor. Coverage spans machining centers, lathes, grinders, and EDM machines.
What machine builders come through the bench?
Drives come through from Mazak, Okuma, Mori Seiki / DMG Mori, Haas, Doosan, Kitamura, Makino, and other CNC OEMs.
Do you provide CNC parameter setup or ladder logic work?
No. Hardware repair only. CNC parameters, ladder logic, machine geometry, and commissioning stay with the customer or integrator. Parameters stored externally must be reloaded after hardware repair.
Can you repair legacy CNC drives no longer supported?
Yes. Discontinued Indramat DDS, older Allen-Bradley Ultra series, and legacy Yaskawa drives come through routinely. The 19,000+ unit donor pool covers a lot of out-of-support hardware.
Do you provide on-site service?
No. Bench repair is the standard service: ship the drive to Westland, MI for rebuild and testing.
How long does a repair usually take?
Lead time varies job to job, partly because parts are often pulled from donor boards. Give us a call with the part number and the situation.
What is the warranty?
One year on parts and workmanship for repairs and rebuilt units. Standard exclusions apply for power surges, contamination, improper installation, and out-of-spec operation.
More from NC Servo
Related repair coverage
Other industry pages and the brand pages most-tied to CNC machine drives.
Servo drive hub
Full directory of drive brands - Allen-Bradley, Siemens, Indramat, Yaskawa, Fanuc, and more.
Industrial robot
Servo drives on welding, material-handling, and assembly robots.
Packaging drive
Servo drives on packaging-line filling, labeling, and palletizing equipment.
Fanuc brand page
Fanuc alpha and beta servo amplifier coverage.
Siemens brand page
SINAMICS S120, 611D, and Siemens drive coverage.
Yaskawa brand page
Sigma series drives across CNC, packaging, and robotics.
What is a servo drive?
Plain-language explanation of servo drives: what is inside, common architectures, and what gets done at the bench.
Repair vs replace
When component-level repair makes sense versus buying new or rebuilt.
CNC machine down? Send a part number
Give us a call or send a part number with the machine context and the symptom. We'll check the donor pool, suggest a rebuilt match if we have one, and walk through repair or cross-brand options if we don't.