Philips 32HFL4372D - 32 inch Philips LCD TV schematic – 715G3861 PSU

Used ICs: A6069H, FAN7529MX [SMPS] control, SPW20N60C3 [FET], SSC9512S-TL

The Q552.1E LA is a new chassis launched in Europe in 2010.  The whole range is covered by PNX8550x main IC so-called NXP TV550 platform.
The major deltas versus its predecessor Q543/Q548 are the DVBS, DLNA1.5+, Wireless Laptop Live (WLL-Dongle), Ethernet, and WiFi Ready (Net-TV) functionality.

Key components of this chassis are
* PNX85500 System-On-Chip (SOC) TV Processor
* TX31XX Hybrid Tuner (DVB-T/C, analogue)
* STV6110AT DVB-S Satellite Tuner
* SII9x87 HDMI Switch
* TPA312xD2PWP Class D Power Amplifier
* LAN8710 Dual Port Gigabit Ethernet media access controller.

Power Supply Unit

Before checking other parts first check whether fuse on the PSU is not broken. Always replace a defective fuse with one with the correct specifications! This part is available in the regular market.

The output voltages to the chassis are:
* +3V3-STANDBY (Stand-by mode only)
* +12V (on-mode)
* +Vsnd (+24V) (audio power) (on-mode)
* +24V (iBoard power) (on-mode)
* Output to the display; in case of
- IPB: High voltage to the LCD panel
- PSL and PSLS (LED-driver outputs)
- PSDL (high frequent) AC-current.

The diversity in power supply units is mainly determined by the diversity in screen sizes.

The on-board DC/DC converters deliver the following voltages (depending on set execution):

* +3V3-STANDBY, permanent voltage for the Stand-by controller, LED/IR receiver and controls; connector 1M95 pin 1

* +12V, input from the power supply for TV550 common (active mode); connector 1M95 pins 6, 7 and 8

* +24V, input from the power supply for DVB-S2 (in active mode); connector 1M09 pins 1 and 2

* +1V1, core voltage supply for PNX85500; has to be started up first and switched "off" last (diagram B03B)

* +1V2, supply voltage for analogue blocks inside PNX85500

* +1V8, supply voltage for DDR2 (diagram B03B)

* +2V5, supply voltage for analogue blocks inside PNX85500 (see diagram B03E)

* +3V3, general supply voltage (diagram B03E)

* +5V, supply voltage for USB and CAM (diagram B03E)

* +5V-TUN, supply voltage for tuner (diagram B03E)

* +V-LNB, input voltage for LNB supply IC (item no. 7T50)

* +5V-DVBS, input intermediate supply voltage for DVB-S2 (diagram B08A)

* +3V3-DVBS, clean voltage for silicon tuner and DVB-S2 channel decoder

* +2V5-DVBS, clean voltage for DVB-S2 channel decoder

* +1V-DVBS, core voltage for DVB-S2 channel decoder.

A +12 V under-voltage detector (see diagram) enables the 12V to 3.3V and 12V to 5V DC/DC converters via the ENABLE-3V3-5V line, and the 12V to 1.8V DC/DC converter via the ENABLE-1V8 line. DETECT2 is the signal going to the Stand-by microcontroller and ENABLE-3V3n is the signal coming from the Stand-by microcontroller.

SMPS schematic

PWB -  component and foil side

Click on the pictures to magnify