: Check the PFC MOSFET and controller if the main filter capacitor is not reaching approximately 400V DC.

The PWM controller IC cracks or shorts out due to voltage spikes. Secondary Rectification and Filtering

⚠️ Many "free" schematic sites bundle .exe downloaders or password-protected RAR files. Always scan with VirusTotal before opening.

[AC Mains Input] ---> [Input Fuse / Bridge] ---> [PFC Stage (~400V)] ---> [SMPS Transformers] ---> [+12V / +24V Output Rails] | v [LED Driver Circuit] No Power / Dead TV (Blown Fuse)

Troubleshooting tips (concise, for electronics-literate users):

Converts alternating current (AC) mains voltage to a stable high-voltage direct current (DC) bus, typically around 400V DC if Power Factor Correction (PFC) is present.

: Optocouplers (e.g., PC817 or similar) providing feedback isolation between the hot (primary) and cold (secondary) sides of the board.

Suppresses high-frequency electrical noise from entering or exiting the mains supply.

Steps up the voltage to drive the LED strips inside the panel, regulating the current to ensure consistent screen brightness without burning out the LEDs. Core Circuit Blocks & Key Components

Acquiring the correct schematic is a non-negotiable first step for any successful repair. Here's where to find them.

*"I know you haven't logged in for a while, but I am standing in front of a dead 17ips72. I don't need the whole book. I just need the pinout for the secondary rectifier and the gate

When the TV turns on with a functional standby light and standard audio, but the screen remains entirely black, focus on the backlight system. Measure the voltage output on the terminal at socket CN5 during initial power-on. If the voltage spikes briefly above 75V and then drops down toward the base secondary rail level, the OB3363 IC is entering over-voltage protection. This behavior typically points to an open circuit within the display panel's physical LED backlight strips rather than a fault on the 17IPS72 circuit board itself.

If the schematic does not immediately reveal the fault, the online repair community is very active for Vestel boards.

The is the motherboard model number for the Lenovo Legion Y720-17IKB gaming laptop. This board is based on the Intel Kaby Lake (7th Gen) platform, paired with NVIDIA Pascal-series graphics (typically GTX 1060 or 1050 Ti).

The Vestel 17IPS72 is a combination board integrating both the and the LED backlight driver onto a single printed circuit board (PCB). It is designed to work with mainboards like the Vestel 17MB120 or 17MB140.

– A smaller archive that has schematics such as Hitachi_55HB6T72U_55289DLB_17MB110‑R2_17IPS72.pdf .

Most variants (such as 17IPS72P) include a PFC controller and MOSFET to boost the input to roughly 400V DC once the TV is fully powered on.