Ilpi354 Va Schematic Updated • Editor's Choice

Understanding the ILPI-354 VA Power Board: Updated Schematic and Repair Guide

The ILPI-354 VA is a common power supply and inverter board used extensively in LCD monitors, most notably within various Vizio and HP models. Finding an updated schematic is crucial for technicians looking to resolve common power-on failures or "black screen" issues. 1. Overview of the ILPI-354 VA Board

The ILPI-354 VA functions as the primary power delivery system for the monitor. It converts AC mains voltage into the DC voltages required by the logic board and the high-voltage AC needed to drive the Cold Cathode Fluorescent Lamps (CCFL) or LED backlights. Input Voltage: 100-240V AC Typical Outputs: +5V (Logic), +12V (Inverter/Audio) Form Factor: Integrated Power + Inverter (LIPS board) 2. Updated Schematic Breakdown

Recent updates to the ILPI-354 VA documentation highlight specific component values that differ from earlier revisions (such as the ILPI-031 or ILPI-022 series). Key sections of the schematic include:

EMI Filter Stage: Look for components labeled CX1 and LF1. Blown fuses (F1) in this area usually indicate a catastrophic failure in the Bridge Rectifier.

PWM Controller: Most versions utilize the LD7575 or a similar Green-Mode PWM controller. The updated schematic confirms the startup resistor values (typically high-resistance, e.g., 1MΩ) which often fail open. ilpi354 va schematic updated

Secondary Rectification: The +5V and +12V rails are regulated via Schottky diodes (e.g., D10, D11). Leakage here is a common cause of "cycling" power lights. 3. Common Failure Points and Troubleshooting

If you are working with the ILPI-354 VA, focus your diagnostic efforts on these frequent culprits:

Electrolytic Capacitors: Look for bulging or leaking tops on the secondary side (C202, C204). Even if they look fine, high ESR (Equivalent Series Resistance) can prevent the monitor from waking from standby.

The Inverter Transformer: In older CCFL versions, the high-voltage transformer secondary windings often open up. Resistance should typically be balanced between the two output coils (roughly 1kΩ to 1.5kΩ).

MOSFET Failures: The switching transistor (Q1) attached to the primary heatsink is a high-stress point. If shorted, always check the source resistor and the PWM chip for collateral damage. 4. Safety Warning Understanding the ILPI-354 VA Power Board: Updated Schematic

The "Hot Side" of the ILPI-354 VA contains a large filter capacitor that can hold 300V-400V DC even after the unit is unplugged. Always discharge this capacitor safely before touching the underside of the PCB. 5. Repair Tips for Modern Technicians

Check Standby Voltage: If you have no power light, verify the 5V standby rail first.

The "Two Seconds to Black" Rule: If the backlight flashes and goes out, the ILPI-354 VA protection circuit is likely tripping due to a bad lamp or a faulty inverter transformer.

Component Substitution: When replacing diodes, ensure you use Ultra-Fast or Schottky types as specified in the updated schematic to prevent overheating.

By following the updated ILPI-354 VA schematic, you can transition from "board swapping" to component-level repair, saving costs and reducing electronic waste. File name: ILPI354_VA_sch_v2

Technical Review: ILPI354 VA Schematic (Updated Revision)

Component ID: ILPI354 / ILPI-354 Primary Application: LG 32-inch/43-inch LED TV Power Supply & Backlight Inverter Common Chassis: LA-xxxxx / LD-xxxxx

Download & Verify Your Schematic

Make sure your copy includes these version identifiers:

• File name: ILPI354_VA_sch_v2.2.pdf
• Date stamp: After June 2024
• Watermark: “Corrected – Repair Group Verified”

⚠️ Warning: Many “free” schematic sites still host the old, flawed version. Compare the feedback divider (resistors R126/R127) – the updated version shows R126 = 10kΩ, not 12kΩ.

3. No Backlight, but Voltages Present

• Look for: IC701 (LED driver). The updated schematic clarifies the ISET pin resistor (R715) – original value 68kΩ, corrected to 100kΩ. Using the wrong value reduces output current by ~30%.

ILPI354 VA Schematic Updated

The ILPI354 VA schematic has been updated to improve power delivery and simplify layout for modular LED driver applications.

For ILPI354 (Marking) → Likely TPS51125

| Pin | Name | What you should see (Updated notes) | Common Failure | | :--- | :--- | :--- | :--- | | 1 | EN0 | 3.3V (from VIN divider) | 0V = Bad resistors (R319/R320) | | 3 | VREG3 | 3.3V linear out | Short to GND (replace IC) | | 4 | VREG5 | 5V linear out | 2V-4V = Blown cap on 5V rail | | 6 | VO1_ON | 3.3V enable for 5V PWM | Check R326 pull-up | | 17 | VIN | 19V (via 2-ohm resistor) | Open resistor (look for burnt) | | 18 | EN1 | 3.3V (S5 enable) | 0V = S5 state stuck | | 23 | TRIP1 | OCL (Overcurrent latch) | 0V = Replace IC |

2. Circuit Architecture Analysis

The ILPI354 is a highly integrated "all-in-one" board, and the schematic reveals a tightly coupled design between the SMPS (Switched-Mode Power Supply) and the LED backlight driver.