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Expert Services

Control Card & Drive Board Repair

Diagnostics and repair for CNC motherboards, drive control cards, and gate drivers.

Service Overview

Control cards process feedback signals and coordinate the actions of power electronics. A fault in a drive's gate driver board can cause the output IGBTs to blow, while a CNC motherboard failure shuts down the operator station. Usha Engineering Services provides component-level repair for drive control cards, gate driver boards, and CNC motherboards. We test logic gates, microcontrollers, and communication ICs to ensure correct signal timing.

Supported Hardware Series & Models:

Fanuc CNC Main Cards

Siemens Sinumerik Boards

ABB Drive Control Cards (SDCS-CON)

Yaskawa Gate Driver Boards

Heidenhain Position Cards

Okuma Control Cards

Common Failure Modes & Diagnostic Codes

Technical Reference Sheet for Engineers

Code / Symptom	Probable Cause	Engineering Remedy
Gate Output Signal Distortion	Degraded charge pump capacitors, failed gate drive optocouplers, or weak isolation transformers	Check gate signal waveforms with high-bandwidth oscilloscope. Replace optocouplers and refresh local SMD capacitors.
CPU Communication Timeout	Failed bus transceivers, damaged Ethernet PHY chips, or corrupted logic gate arrays	Test local oscillator crystals, check voltage rails, replace communication buffer transceivers, and reflow logic chips.
Analogue Input Signal Drift	Burnt input voltage dividing resistors, or drifting operational amplifier reference circuits	Replace high-precision metal film resistors and swap drifting op-amps with matched ultra-low drift replacements.
RAM / Flash Write Failures	Write-cycle wear on local static RAM chips or EEPROMs from frequent configuration adjustments	Desolder damaged memory IC, read old data using flash programmer, write to a new memory chip, and resolder.

Our Premium 6-Step Component-Level Repair Process

How we restore electronic components to manufacturer specifications

Incoming Visual & Thermal Inspection

Every unit is registered and subjected to high-definition visual inspection and thermal scanning. We identify blown trace lines, scorched resistors, swollen capacitors, and signs of liquid ingress before applying any power.

In-Circuit Analog Signature Analysis

Using advanced Tracker/Signature Analyzers (such as Huntron Trackers), we test passive components (resistors, diodes, capacitors, inductors) and active ICs while in-circuit. This safe, power-off testing compares component electrical signatures against known-good standards.

Semiconductor Power-Stage Diagnostics

For VFDs and servo drives, we test the high-power rectifier and IGBT inverter stages. We check the gate-drive circuit paths, desaturation protections, and replace gate optocouplers to prevent catastrophic future failures.

Microscopic Solder & SMT Reflow

Using ISO-certified temperature-controlled desoldering stations, our IPC-trained technicians replace damaged components. We execute precision micro-soldering under stereo-zoom microscopes for multi-layer PCBs.

Controlled Bench & Load testing

After repair, units are powered on via variable-voltage current-limiting power supplies. We run full closed-loop tests under real load conditions—testing communication links, analog/digital feedback loops, and thermal efficiency.

Final QC Certification & Protective Coating

The repaired PCB is cleaned in an ultrasonic chemical bath to remove flux residues. We apply a high-grade conformal coating to protect against moisture, dust, and corrosive industrial oils before releasing the unit with our warranty.

ISO 9001:2015 Certified

Why Choose Usha Engineering?

26+ Years of B2B Expertise

Established in 2000, we possess over a quarter-century of hands-on industrial electronic repair experience. We are an ISO 9001:2015 Quality Management System certified company.

Up to 70% Cost Savings

Repairing high-end industrial controllers and drives with Usha Engineering is significantly more cost-effective than purchasing expensive new OEM replacement units, which also require configuration.

Advanced Component-Level Lab

Our Panchkula HQ facility features state-of-the-art diagnostic equipment including logical analyzers, digital oscilloscopes, curve tracers, thermal imagers, and dedicated load test benches.

Pan-India Logistics & Quick Turnaround

We accept units shipped via secure courier from anywhere in India, offering express 48-hour turnarounds for critical breakdowns to minimize factory downtime.

Industries We Serve

Steel & Metallurgy

VFDs and PLCs controlling blast furnace loaders, rolling mills, heavy crane lifts, and cooling fans.

Textile & Spinning Mills

High-speed servo drives, HMI panels, and control cards on spinning frames, carding machines, and weaving looms.

Paper & Packaging

Multi-drive tension control systems, synchronous motors, and PLC controllers on web presses and slitting lines.

Pharmaceutical & Chemical

HMIs, PCBs, and control modules in pill press machines, packaging lanes, centrifuge drives, and mixing vessels.

CNC & Automotive Machining

Precision spindle drives, servo controllers, and logic units in 3-axis and 5-axis CNC machining centers.

Warranty Protection

3-Month Service Warranty

We stand behind our work. All board-level repairs performed by Usha Engineering Services are covered by a comprehensive 6-month warranty on replaced components and workmanship. We use only original, high-grade semiconductor parts sourced from certified global distributors.

Need Help Immediately?

Submit a diagnostics ticket or speak directly with an engineer to get a free estimate and arrange unit pickup.

Frequently Asked Questions

Clear answers regarding repair procedures, pricing, and warranties

What is a gate driver board?

It is the intermediate card that receives low-voltage logic commands from the main control card and amplifies them into high-current signals to open and close power transistors (IGBTs) safely.

Can you repair custom firmware on control cards?

Yes, if the physical flash chip is readable. We back up the firmware, verify its integrity, flash it onto a new chip, and replace the old hardware.

How do you verify gate signal timing?

We run the card on a specialized test bench and use multi-channel oscilloscopes to confirm that the switching signals for the high-side and low-side IGBTs do not overlap.

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