The Vestel 17IPS72 is a widely used power supply and LED driver board found in various LED TVs (e.g., Philips, Hitachi, Bush). Repairing it involves understanding its core stages: the Power Factor Correction (PFC), the primary switching stage, and the secondary output rails. 1. Getting the Schematic
Before starting, download the specific revision for your board (e.g., R3 or R4), as component values can vary.
Elektrotanya (17IPS72R3): A reliable source for free service manual downloads.
Scribd (17IPS72-R4): Often has detailed PDFs of later revisions including component layouts. 2. Core Circuit Stages
PFC Controller (U1): Regulates input power to provide a steady +400V DC for downstream components. Common parts include the FAN7529 controller and high-side resonant MOSFETs.
Primary Switching: Driven by an oscillator that provides pulses to the gate of the main MOSFET. If this oscillator fails, the board will show "no signs of life".
Secondary Outputs: Supplies critical rails like +12V, +12V_STBY (standby), and higher voltages (e.g., +75V) for the LED backlights. 3. Common Faults & Troubleshooting
Vestel 17IPS72 is a commonly used switch-mode power supply (SMPS) found in various LED TV brands such as JVC, Hitachi, and Philips. Understanding its schematic work involves breaking down its primary stages, from mains input to output regulation. Core Circuit Sections
The 17IPS72 board operates on a flyback-based design with the following primary functional blocks: PFC (Power Factor Correction) Stage:
Many revisions (like the 17IPS72P) include a dedicated PFC controller chip and MOSFET. This section regulates input power to provide a stable rail for downstream components. Standby Power Supply: This "always-on" section typically uses an ICE3BR1765J PWM controller. It converts rectified mains (~325V DC) into a stable 17ips72 schematic work
rail. This rail powers the TV's mainboard microcontroller and IR receiver while in standby. Main Output Rails: When the mainboard sends a signal, the main supply activates secondary rails, usually High-current Schottky diodes
(like STPS20H100CFP) are used to rectify these voltages for the backlight and audio sections. Troubleshooting & Common Failure Points
If you are analyzing a faulty board, the schematic highlights several critical areas for measurement: No Standby Power (No LED): Check the primary bulk capacitor for ~320V DC. Inspect the small VCC electrolytic capacitor
(often C313 or C316) and the startup resistors in the standby PWM section.
Verify the secondary Schottky diode on the 5V rail; a shorted diode here is a frequent failure point. Voltage Pulsing/Unstable Output:
If voltages are pulsing (hunting), it often indicates a failure in the feedback loop or the oscillator driving the MOSFET not maintaining continuous oscillation. optocoupler feedback components. Reference Resources
For detailed pinouts and component values, you can find official schematic downloads on platforms such as: Elektrotanya
(Offers free PDF service manuals and schematics for various revisions). (Hosts diagrams for the PFC and LED driver variants).
Modern power supplies contain lethal high-voltage capacitors that can hold a charge even after the TV is unplugged. Always discharge these safely before testing. Repeater Builder® Are you currently repairing a specific fault The Vestel 17IPS72 is a widely used power
The Vestel 17IPS72 is a common power supply unit (PSU) and LED driver board found in numerous LED TV brands like JVC, Philips, and Bush . It is known for its relatively low build quality, often leading to solder joint fatigue and capacitor failure . Core Circuit Sections
The 17IPS72 schematic is generally divided into several key functional stages:
EMI Filter & Rectification: This initial stage receives AC mains power. It uses a bridge rectifier (often a D25XB80 or similar) and filtering capacitors (100nF, 275V) to convert AC to a raw DC voltage .
Power Factor Correction (PFC): Regulated by a PFC controller (like the FAN7529 in some revisions), this section uses a MOSFET and inductor to boost and stabilize the input voltage to approximately 400V DC for the main power conversion .
Standby & Main Power Conversion: This stage provides the standard working voltages. Common outputs include +12V and +5V Standby . A chopper control MOSFET (such as MMD70R600P) driven by an IC (like BM1Q1) handles the switching .
LED Driver Stage: This section boosts the voltage to the level required by the TV's LED backlight strips. Faults here often result in sound but no picture . Common Troubleshooting Points
If the board is "dead" (no standby lights), initial checks should focus on the primary side:
Fuse & Rectifier: Check the 3.15A fuse and the four rectifier diodes. Shorted diodes are a frequent cause of blown fuses .
Capacitor Wear: Look for bulged electrolytic capacitors, especially on the secondary output side. These boards are known for pushing capacitors near their rated voltage, leading to premature failure . Mastering the 17IPS72 Schematic Work: A Comprehensive Guide
Voltage Instability: If the standby light is flickering, it may indicate a failure in the oscillation circuit, where the PSU attempts to start but repeatedly cuts off .
Backlight Faults: If the TV has sound but no image, check for a shorted boost MOSFET or a failed LED controller IC in the driver section .
A legitimate PDF schematic for the NM-B191/17IPS72 contains between 45 and 60 pages of critical data:
Let’s run a real diagnostic using the schematic and boardview.
Step 0: Remove all peripherals, RAM, SSD. Connect DC supply at 19V/3A.
Step 1: Measure +PWR_SRC at the drain of the first isolation MOSFET (PQ102). Schematic Ref: Page 6, label "CHARGER INPUT."
Step 2: Measure +3VALW at C2302 (near the PCH). If 0V, go to Page 4 (Power tree). See +3VALW is made by PU201. Check Pin 7 (VIN) = 19V. Pin 6 (EN0) = 3.3V. If EN0 is missing, trace back to PWR_SRC_DIV through resistors PR213/PR214.
Step 3: Assuming 3.3V and 5V are present, press the power button. Does PWRBTN#_EC toggle? Probe pin 36 of the EC (IT8226VG). No toggle? Bad power button board (check connector JEC1 using boardview).
Step 4: If toggle is good, measure SUSP#. Probe Pin 99 of the EC. Should go from 0V to 3.3V. If it stays 0V, the EC is dead or its firmware is corrupt (requires reballing or replacement with pre-programmed EC).
Step 5: Next, check EC_RST# (EC Reset). Pin 102 of EC. Must be 3.3V constantly. If it pulses or is 0V, the +3VLP rail is unstable or the reset capacitor (C8802) is leaky.
Step 6: Finally, check PLT_RST# (Platform Reset) at PCH pin J12 (or the BIOS chip pin 6). This is the final master reset. 0V means the PCH never received all power-good signals. Use the schematic to trace back SYS_PWROK and PCH_PWROK.