PLC Controllers — The Heart of Every Production Line
A PLC failure stops the entire production line, press, CNC lathe, welding robot, or packaging system. We service PLC controllers from all major manufacturers for industrial plants across London, Birmingham, Manchester, Leeds, Glasgow, Frankfurt, Berlin, Hamburg, Munich, Stuttgart, Düsseldorf, Vienna, Graz, Zurich, Basel, Amsterdam, Rotterdam, Antwerp, Brussels, Paris, Lyon, Milan, Turin, Bologna, Rome, Prague, Brno, Bratislava, Warsaw, Poznan, Wroclaw, Katowice, Gliwice, and Gdansk.
A new Siemens S7-400 CPU module costs €3,000–12,000 with lead times of 6–14 weeks. Component-level repair restores full function in 3–7 working days for €280–1,400.
PLC Manufacturers and Supported Models
Siemens (Germany) — SIMATIC
The most commonly repaired PLC in Europe. We cover the full portfolio:
- S7-300: CPU 312–319, SM/FM/CP modules, PROFIBUS connectors. Widespread in food, chemical, and automotive industries since 1994.
- S7-400: CPU 412–417, 412H/414H (redundant). Buffer batteries and filter capacitors are particularly vulnerable after 15+ years.
- S7-1200: CPU 1211C–1217C. Most common failure: burned transistor output circuit after a voltage surge.
- S7-1500: CPU 1511–1518, ET 200SP/MP modules. Modern PROFINET IRT platform. BGA repair of ARM processors and Xilinx FPGAs.
- WinAC / IPC: SIMATIC IPC427, IPC477, IPC677 — industrial PCs with Windows Embedded.
Allen-Bradley / Rockwell Automation (USA)
- SLC 500: CPU 5/01–5/05. Classic 1990s PLC. Power supply and CPU EEPROM most commonly fail.
- MicroLogix: 1000, 1100, 1200, 1400, 1500. Most common failure: relay output module, built-in power supply.
- ControlLogix: CPU 1756-L55 to L85. Most common failure: SHARC DSP or BGA FPGA damaged by ControlBus surge.
- CompactLogix: CPU 1769-L23 to L45. Popular in small and medium installations.
- PLC-5: Legacy platform CPU 5/10–5/80. End-of-life — repair is the only option.
Mitsubishi Electric (Japan) — MELSEC
- FX3: FX3U, FX3UC, FX3GA, FX3GE, FX3S. Most common failure: RS-232/RS-422 comms, extension modules, 5V PSU.
- Q-series: Q00–Q25UDEH. BGA processor failure after power surge.
- iQ-R: R04–R120. BGA and Altera FPGA repair.
- iQ-F (FX5): FX5U, FX5UC, FX5UJ. Built-in Ethernet. PHY chip failure after ESD surge.
Fanuc (Japan) — PMC/CNC
- Series 0i: 0i-MD/TD/MF/TF. Main board CPU BGA, axis card, I/O module.
- Series 30i / 31i / 32i / 35i: FPGA Xilinx Spartan repair on the axis board.
- Robot R-30iA / R-30iB / R-30iB Plus: CPU board, safety board, servo modules.
Beckhoff (Germany) — TwinCAT
- CX1000–CX2040: Embedded PCs with TwinCAT. Power supply, DDR RAM, eMMC/SSD, EtherCAT I/O.
- C6015–C6030: Industrial PCs. PSU capacitors, Intel CPU after surge.
Schneider Electric — Modicon
- M340: CPU BMX P34 series. PSU PCB repair (capacitors, MOSFETs).
- M580: CPU BME P58 series. PowerPC BGA repair.
- Premium / Quantum: Legacy platforms. Wide install base in France, Belgium, Spain.
Also Supported: ABB AC500, Omron CP1H/CJ2M/NJ/NX, B&R X20/X90, Keyence KV-8000, Panasonic FP7.
Repair Techniques — BGA, SMD, FPGA, Memory
BGA (Ball Grid Array) Repair
Processors, FPGAs (Xilinx, Altera), DSPs (TI SHARC), and communication ASICs in industrial PLCs are all BGA-mounted. Common BGA failure modes:
- Solder joint fatigue cracks from thermal cycling (8–15 years in installations with temperature swings)
- Galvanic corrosion of solder balls in humid environments
- Mechanical damage from vibration (pressing machines, vibrating conveyors)
- ESD damage during unauthorised servicing
Our BGA repair process: visual and X-ray inspection → thermal extraction (profiled hot-air station) → pad cleaning → BGA reballing with SAC305 or Sn63Pb37 balls via BGA stencil → reflow with J-STD-020 profile → functional test on dedicated rack.
SMD Component Repair
Most commonly failed SMD components on PLC boards: electrolytic/MLCC capacitors (ESR increase), output MOSFETs (inductive surge damage), LDO/DC-DC regulators, TVS diodes and varistors (lightning strikes), communication transceivers (RS-485, PROFIBUS SPC3/VPC3+, Ethernet PHY RTL8211/KSZ8081).
FPGA Recovery
Xilinx Spartan-3/6/7, Artix-7, Kintex-7 and Altera Cyclone II/III/IV/V FPGAs are used in modern PLCs for I/O processing, communication acceleration, and co-processing. We repair: FPGA replacement after ESD damage, SPI configuration memory (W25Q64, M25P64, S25FL128) recovery and reprogramming.
Memory Recovery (Flash, SRAM, FRAM)
- Flash NOR: PLC program stored in Intel 28F, Spansion S29GL, Micron MT28. Replacement and reprogramming with professional programmers (Xeltek, Hi-Lo Systems) even without a backup copy.
- Battery-backed SRAM: S7-300/400, SLC 500, PLC-5 — CR2032/CR2450/LS14500 battery replacement + data retention verification.
- FRAM: Mitsubishi iQ-R, Omron NJ/NX. Data error repair.
Most Common PLC Failures
- 24V DC surge: Destroys input optocouplers, output MOSFETs, internal regulators, comms transceivers.
- Internal PSU failure: After 10–20 years electrolytic bulk capacitors (1000–4700µF) lose capacitance — internal voltages become unstable, CPU hangs or does not start.
- ESD damage to CPU: 1,000–15,000V ESD from unprotected service work destroys MOS gate structures in CMOS processors and FPGAs.
- Connector corrosion: In humid or chemical environments (food, galvanic, chemical plants) — backplane, expansion card, and power connectors corrode.
- Loss of user program: Flat backup battery + failed Flash = lost program. We recover programs from NOR Flash in-circuit and off-circuit in most cases.
Our Equipment
- JBC HDE-9 BGA/SMD rework station (±2°C thermal profile control)
- Leica S9i stereo microscope (7.5–120× magnification)
- X-Ray fluoroscope for non-destructive BGA joint inspection
- Xeltek SuperPro 6100N and Hi-Lo ALL-100 programmers (150,000+ device support)
- Protocol analysers: PROFIBUS, PROFINET, EtherNet/IP, EtherCAT, CANopen, DeviceNet
- Functional test racks: S7-300/400/1200/1500, ControlLogix, Modicon M340/M580
- SMD 0201 rework under microscope, SAC305 LF and Sn63Pb37 solder
Pricing
- PLC power supply repair (capacitors, MOSFETs, TVS diodes): €180–480
- BGA processor / FPGA repair: €380–920
- Digital output module repair: €160–420
- Communication interface repair (PROFIBUS, PROFINET, EtherNet/IP): €180–380
- Flash/SRAM memory recovery + battery replacement: €80–280
- Digital input repair (optocouplers): €120–320
- Built-in HMI / display repair: €120–340
- Full CPU repair (PSU + BGA + memory): €520–1,400
- Diagnostic without repair: €80 (deducted from repair cost)
- Express 48h service: +€120
Return courier to Germany, UK, France, Poland, Czech Republic, Slovakia, Netherlands, Belgium, Austria: included. Italy, Spain, Scandinavia: €35–55 supplement. 12-month warranty. No-fix no-fee.
Service accepts shipments and performs diagnostics Monday to Friday, 08:00–16:00.