CNC Power Supply Dead — Ship It to Us, Machine Back Online in Days
A faulty CNC power supply module puts the entire machine out of service. A replacement Fanuc PSM-11/15/26/45 costs €1,800–6,500 new from Fanuc. A Siemens SINUMERIK SLM (Smart Line Module) or SIM (Single Motor Module): €2,000–5,500. A Heidenhain UVR power supply: €1,200–3,200. Our component-level SMPS repair costs €320–980 and the machine is back in production in 2–4 working days.
Customers from Berlin, Hamburg, Stuttgart, Munich, Frankfurt, Vienna, Zurich, Prague, Brno, Bratislava, Warsaw, Lodz, Wroclaw, Milan, Turin, Bologna, Barcelona, Madrid, Amsterdam, Lyon, and Gothenburg ship us CNC power modules via DHL Express or UPS — the module arrives, we diagnose within 24h, repair within 48–96h, return same day as completion.
Fanuc PSM (Power Supply Module) Repair
The Fanuc PSM is the heart of Fanuc servo and spindle drive systems. When it fails, nothing moves. Common faults by model:
- PSM-11 / PSM-15 / PSM-26 / PSM-45 — Alarm AL-01 (Low voltage in DC link): Precharge relay failure (contact wear after 5–8 years), precharge resistor thermal failure, or input rectifier diode bridge partial failure (one diode high-resistance causing DC bus droop under load). We test each diode individually and replace only the failed elements.
- AL-09 (Discharge circuit disconnected): Discharge IGBT gate drive fault. The discharge circuit drains the DC bus on E-stop — when it fails, the drive trips on overvoltage during deceleration. Gate drive optocoupler replacement.
- AL-09 / regeneration fault: Active front-end IGBT failure in regenerative PSMs (A-type PSM). We source matching Infineon IGBT pairs and rebuild the regenerative bridge.
- Control power supply failure (5V, 15V, 24V rails): The auxiliary SMPS on the PSM control board fails — outputs collapse, PSM shows no LED activity. We replace the PWM controller IC (typically UC3842, UCC28600 or similar), optocoupler feedback chain, and output rectifier diodes.
- Communication fault with CNC (FSSB/HSSB link): Fiber-optic SFP transceiver degradation on the PSM control board causing CNC-to-amplifier communication loss. We replace the optical transceiver module.
Siemens SINUMERIK Power Module Repair (SLM, ALM, SIM, BLM)
- SLM (Smart Line Module) — F06000 (Internal IGBT fault): Active rectifier IGBT failure in the SLM causing DC bus undervoltage. The SLM uses a 6-pulse active front end — IGBT replacement requires matched gate drive timing and deadtime verification. Our repair includes full load testing on a motor simulator.
- SLM — F30001 (Overcurrent in active rectifier): Gate drive desaturation fault — individual IGBT gate drive optocoupler failure. We replace the HCPL-316J or CONCEPT 2SD315A drivers and retest.
- BLM (Basic Line Module) — DC bus capacitor failure: 100Hz audible ripple, F30005 (DC bus voltage ripple excessive); we replace all electrolytic capacitors in the DC bus bank (matched Nichicon or Nippon Chemi-Con HB series, 105°C rated).
- ALM (Active Line Module) — precharge relay failure: F30011 (precharge timeout); relay contact resistance increase causing incomplete DC bus charge. Relay replacement and contact resistance verification.
- Control power supply (X1 24V fault): Internal 24V SMPS failure on the module control board; PWM controller and output stage repair.
Heidenhain UVR Power Supply Repair
Heidenhain TNC 530, TNC 620, TNC 640, iTNC 530 machines use the UVR (Umrichter Versorgungseinheit — supply converter) module:
- UVR error "Mains undervoltage": Input filter capacitor failure reducing mains voltage seen by the rectifier; also triggered by failed inrush NTC limiter. We replace the NTC and input capacitors.
- UVR DC bus overvoltage on braking: Braking chopper IGBT failure — the module cannot dump regenerative energy from axes braking together. IGBT module replacement with load test.
- UVR "Drive system not ready": 24V auxiliary supply failure on the UVR control card; internal DC-DC converter IC failure causing DRIVE-READY signal to drop.
- UVR capacitor bank ESR increase: Machine shows reduced axis performance and occasional DC bus errors; we perform full ESR measurement and replace aged capacitor banks.
Mitsubishi MDS-B / MDS-C1 / MDS-EJ Power Module Repair
- Alarm 50 (Control power supply abnormal): Internal 5V/15V SMPS failure; PWM controller IC replacement and output stage repair.
- Alarm 01 (Overcurrent): IGBT output bridge failure; source of matched Mitsubishi CM-series IGBTs and full bridge rebuild.
- Alarm 52 (Communication error with CNC): SSCNET III optical transceiver degradation. We replace the optical TX/RX module and verify signal integrity.
- Alarm 10 (Power supply regeneration alarm): Regenerative IGBT or braking circuit failure in MDS-EJ spindle and servo power modules.
How to Ship, Pricing, and Warranty
Remove the PSM/SLM/UVR/MDS module from the cabinet, note all parameter settings (photograph the display if accessible), pack with 5cm foam in a double-wall carton, ship DHL Express or UPS to our facility. We confirm receipt same day, deliver a diagnostic report within 24h.
Fanuc PSM repair: €380–980. Siemens SLM/ALM IGBT repair: €480–1,100. BLM capacitor bank replacement: €220–480. Heidenhain UVR repair: €320–750. Mitsubishi MDS repair: €340–820. Return courier to Germany, Austria, Czech Republic, Slovakia, Poland: included. Return to Italy, Spain, France, Benelux: €35 supplement. Turnaround: 2–4 working days. 12-month warranty. No-fix no-fee.