AC PCB Diagnostics & Repair
Precision micro-electronics diagnosis for Inverter and Non-Inverter AC motherboards, IPM power modules, microcontroller error codes, and sensor bus communication faults.
100% adjusted into repair invoice if approved. Component repair starts at ₹1,200.
Common PCB Failure Symptoms We Diagnose
Modern Inverter ACs rely on high-frequency communication between the indoor evaporator unit and the outdoor condenser. Identifying these 5 symptom clusters isolates motherboard damage quickly.
Blinking Error Codes (E1, E6, F3, CH05)
Indicates a serial communication drop between the indoor display controller and the outdoor inverter PCB. Usually caused by optical-isolator breakdown or corrupted sensor bus data lines.
Outdoor Unit Dead / No Compressor Kick
Indoor AC blows lukewarm air while the outdoor fan or inverter compressor stays dead. Typically driven by blown IPM (Intelligent Power Module) bridge or shorted 450V electrolytic filter capacitors.
Unit Completely Dead / Zero Power LED
No beep, no LED display on power up. Often caused by voltage surges blowing the primary Metal Oxide Varistor (MOV), onboard ceramic fuse, or the primary Switched-Mode Power Supply (SMPS) switching IC.
Indoor Fan High-Speed Lock or Erratic
Blower fan runs permanently on 100% max speed without responding to remote, or stops after 3 minutes. Driven by damaged solid-state AC triac switch or hall-effect pulse feedback receiver failure.
Constant MCB / Inverter Fuse Tripping
Switching the AC on immediately causes the home miniature circuit breaker (MCB) or stabilizer to trip. Points to shorted bridge rectifiers, ruptured IGBT gate drives, or PFC inductor line short.
Not sure which error code applies?
Our mobile engineers carry digital diagnostic probes for Daikin, Voltas, LG, Mitsubishi, Hitachi, and Blue Star AC inverter lines.
Systematic 4-Stage Diagnostic & Bench Repair Workflow
We treat air conditioning motherboards like advanced aviation electronics. Every repair follows strict electrostatic discharge protocols and calibrated voltage rails verification.
On-Site Signal & Rail Tracing
In-situ Fluke multimeter probing of main DC voltage rails: 300V high-voltage bus, 15V gate driver, 5V microcontroller logic, and 3.3V temperature thermistor supply.
Lab-Grade Bench Micro-Soldering
Transfer to our static-safe lab bench. Hot air rework removal of charred SMD components, desoldering blown IPM or IGBT power arrays, and soldering genuine spec-matched ICs.
Simulated Load & Frequency Rig
The repaired circuit is mounted on our BLDC motor load simulator. Oscilloscope verification confirms stable PWM (Pulse-Width Modulation) waveform generation to compressor windings.
Conformal Seal & Re-installation
Application of aerospace-grade dielectric silicone lacquer protecting traces from humid monsoon corrosion and geckos. Doorstep re-assembly followed by continuous 30-min run load test.
Honest Repair vs. Replacement Benchmark
Most general technicians immediately demand ₹8,000 to ₹12,000 for an entire AC motherboard replacement because they lack micro-soldering capabilities. Uni Finish operates differently:
We desolder burnt individual diodes, bridge rectifiers, fan triacs, and IPM chips. Saves you up to 75% compared to OEM dealer replacements.
Authorized brand centers default to full board replacements without checking if a ₹40 varistor or ₹350 relay was the only blown element.
Uni Finish Lab Benchmark Record
Transparent PCB Pricing Matrix
No hidden service charges or mysterious add-ons. Clear component-level breakdown with our 100% inspection fee offset.
PCB Diagnostic Visit
Full doorstep Fluke probe analysis across indoor and outdoor units with error code decoding.
- check_circle Adjusted 100% into final bill
- check_circle Includes power & grounding test
- check_circle Firm quote before any rework
Minor Component Repair
Replacement of burnt passive or discrete parts that protect the core microcontroller.
- check_circle Power Relays & MOV Varistors
- check_circle Blown ceramic fuses & thermistors
- check_circle Electrolytic buffer capacitors
Major IPM / IGBT Rework
High-voltage inverter power module desoldering and micro-processor circuit level repair.
- check_circle Intelligent Power Module (IPM)
- check_circle IGBT high-speed power transistors
- check_circle Optocoupler communication arrays
Motherboard Replacement
Genuine factory board replacement when MCU silicon is permanently cooked or unrecoverable.
- check_circle 100% Genuine OEM factory board
- check_circle Zero retail markup on spare part
- check_circle Standard fitment & 30-min run test
Frequently Asked Questions
Clear, honest engineering answers to help you navigate AC motherboard repairs.
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AC Compressor Repair
Run capacitor replacement, terminal pin de-carbonization, hard-start kit installation, and internal thermal protector testing.
Quiet Airflow
AC Fan & Blower Repair
Eliminate vibration noises and rattles. Cross-flow blower wheel replacement, shaft bearing lubrication, and motor mount realignment.
Got an Unresponsive AC or Error Code Blinking?
Don't get misled into an expensive ₹10,000 motherboard replacement. Book certified micro-electronics engineers for precision doorstep diagnostics.