Includes standard protection components like a fuse, thermistors for surge protection, and a bridge rectifier to convert AC to raw DC. PWM Control:
: Updates to the schematic often focus on the LED driver circuits (e.g., TPS61199 ) if the monitor uses an LED rather than CCFL backlight . Troubleshooting Guide
Based on the specific designation (commonly associated with LG Display panels) and the context of an "updated schematic," this review analyzes the technical service documents used for repairing specific LG LED/LCD backlit televisions.
Features a bridge rectifier and a large filter capacitor. This section converts AC mains to high-voltage DC.
When replacing diodes, ensure you use Ultra-Fast or Schottky types as specified in the updated schematic to prevent overheating.
| Ref Des | Function | Value | Notes | |---------|----------|-------|-------| | F101 | Primary fuse | 3.15A / 250V | Slow-blow | | IC901 | PWM controller | LD7535 (or compatible) | Pin 5 now correct | | QB801 | Backlight boost MOSFET | 60V / 3A | AO4404A | | R321, R322 | LED current sense | 2.2Ω, 1% (each) | Parallel | | R715 | ISET for LED driver | 100kΩ | Critical for brightness |
[ AC Input: 100-240V ] ──> [ EMI Filter & Bridge ] ──> [ Primary SMPS (PWM/MOSFET) ] │ ┌────────────┴────────────┐ ▼ ▼ [ Secondary DC Rectifier ] [ LED Backlight Driver ] │ │ ▼ ▼ [ 5V Output to Scaler ] [ High-Voltage LED+ Rail ] 1. AC Input & Hot-Side EMI Filtering
Always double-check that your replacement PCB features the branding stamped directly on the silk-screen layer to prevent mounting layout errors or voltage connector mismatches.
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.
Make sure your copy includes these version identifiers:
Would you like help interpreting what the software claims to measure, or finding scientific critiques of this technology instead?