SAMSUNG TFT LCD TV SMPS SCHEMATIC T32LIPS-VE - Troubleshooting

Samsung TFT LCD TV Power Supply Circuit Diagram T32LIPS-VE - (Liquid Crystal Display) Integrated Power Supply - Troubleshooting

Used ICs: SEM3040 – SD10N60-FET – FDD5N50U-FET - ICE2QR0665Z – PC802-Opto-coupler – KIA393F – BD9893F

Troubleshooting

The fuse FS801S blows up, as soon as the set is powered ON.

> Check the VX801S – INR14D751 (Metal Oxide Varistor) for short.

> Check the CY803S – 100pf 400v disc capacitor for short.

> Check the capacitor CX801S 0,47uF for short.

> Check both the capacitors CY802S & CY801S (220pF 400V) for short.

> Check the capacitor CX802S 0.47uF for short.

> Check AC mains bridge rectifier BD801S TS4B05G for any leakage.

> Check QP801S SD10N60 FET for short.

The fuse FM802S blows up when the set is switched ON.

In most cases, this could happen when ICUM801S ICE2qr0665Z have internal short circuit.  Check it by replacing it with same number IC.

Check the capacitor CM822 47pF 1KV for open.  If this capacitor have open circuit, it will cause the IC to blow up.  Evan though, it is a very small component, the function to it when the set switch ON is great.  Check its 2 solder terminals for any loose contact.  When replacing this IC, check the all the zener diodes connected to ground from pin1, 3 & 7 for short circuit.  It will be best to replace these zener diodes along with this IC.

The set do not switch ON.  It may switch ON after several attempts.

Check all the resistors RB831, RB832, RB833, RB834, RP831, RP832, RP833 & RP834.  If anyone among these transistors has open circuit, or has developed high resistance value, this type of fault can occur.  Replace all of these resistors at the same time.

If the SMPS switching IC SEM3040 do not get supply voltage at its pin-8, the power supply won’t start up.  If you have measured a shorted FET (SD10N60), surely the SMPS control IC SEM3040 too might have been damaged. If the FET has found defective (shorted); be sure that here is no loose solder terminals to both the connections of CP807 220pF 1Kv.  If suspected it to be faulty, replace it with a new one.  A damaged capacitor at this place might cause FET to blow up frequently.

CIRCUIT DIAGRAM - POWER & BACK-LIGHT INVERTER

This type SMPS board have been used with many Toshiba and Vestel LCD TV models too.  Check out the IC numbers used as reference.

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