Philips 27PS60S321 manual Repair Tips, Set is dead and makes hiccuping sound

Models: 27PS60S321

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Repair Tips

Below some failure symptoms are given, followedby a repair tip.

zSet is dead and makes hiccuping sound

"Main Power Supply" is available. Hiccupping stops when L5561is de-soldered, meaning that problem is in the "Main Power Supply"line. No output voltages at LOT, no horizontal deflection. Reason:line transistor 7460 is defective.

zSet is dead,and makes no sound

Check power supply IC 7520. Result: voltage at pins 1,3, 4, 5 and 6 are about 180 V and pin 8 is 0 V. The reason why thevoltage on these pins is so high is because the output driver (pin6) has an open load. That is why MOSFET 7521 is not able to switch.Reason: feedback resistor 3523 is defective. Caution : Be careful measuringthe gate of 7521; circuitry is very high ohmic and can easily bedamaged!

zSet is in hiccupmode and shuts down after 8 seconds Blinking LED (setis in SDAM mode) indicates error 5. As it is unlikely that P "POR"and "+8V protection" happen at the same time, measure the"+8V" supply. If this voltage is missing, check transistor7480.

zSet is in non-stophiccup mode

Set is in over-current mode; check the secondary sensing (optocoupler 7515) and the "Main Power Supply" voltage. Signal "Stdby_con"must be logic low under normal operation conditions and goes tohigh (3.3 V) under standby and fault conditions.

zSet turns on,but without picture and sound

The screen shows snow, but OSD and other menus are okay.Blinking LED procedure indicates error 11, so problem is expectedin the tuner (part reference number 1000). Check presence of supplyvoltages. "Vlotaux+5V" voltages at pin 5 and 7 are okay;"VT_supply" at pin 9 is missing. Conclusion: resistor 3460is defective.

zSet turns on,but with a half screen at the bottom. Sound is okay

Blinking LED (set is in SDAM mode) indicates error 3. Check"Vlotaux+11V" and "+50V". If they are okay, problemis expected in the vertical amplifier IC 7471. Use an oscilloscopeto measure the waveform on pin 17 of the UOC. Also measure the waveformat pin 1 of IC 7471. If the signal there is missing, a defectiveresistor R3244 caused the problem

7/8/2004

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Philips 27PS60S321 manual Repair Tips, Set is dead and makes hiccuping sound