Philips 42PFL3606H/58 Not powering on, no power indicator - PSU problem?

[dick_barton]

Re: Philips 42PFL3606H/58 Not powering on, no power indicator - PSU problem?

The voltage at the emitter should be around 12v to 15V. Trunks81 could give you the correct figure. So maybe something could be loading this supply.

Can you meaure the resistance of IC902 between VCC (pin 8) and ground (pin 6)

With Q907 lifted out of circuit what is the voltage across C946

[trunks81]

Re: Philips 42PFL3606H/58 Not powering on, no power indicator - PSU problem?

This my measurement from an other topic !
Also at one of my boards Q906 was defective

[R_J]

Re: Philips 42PFL3606H/58 Not powering on, no power indicator - PSU problem?

I would replace C946 for a start, it is likely bad even though the capacity is reading close

[DrOetker]

Re: Philips 42PFL3606H/58 Not powering on, no power indicator - PSU problem?

The voltage at the emitter should be around 12v to 15V. Trunks81 could give you the correct figure. So maybe something could be loading this supply.

Can you meaure the resistance of IC902 between VCC (pin 8) and ground (pin 6)


With Q907 lifted out of circuit what is the voltage across C946

Resistance between VCC (pin 8) and ground (pin 6) on IC902 is 233k ohms in both directions.

I also measured voltage across Q915 (part of the brown out circuit, equivalent to Q906 on trunks81's board) anq Q918 while the mainboard was plugged in.

Q915:
B = +6.12V
E = +5.84V
C = 0.00V

Q918:
B = 0.00V
E = 0.00V
C = +314V

That means that on my board the brown out circuit is active, is that correct?

I'm sorry, I don't get it, do I need to fully lift Q907 or just one pin of it? What will be easier, to do it using a heath gun or with soldering iron?

I would replace C946 for a start, it is likely bad even though the capacity is reading close

I will replace C946 tomorrow and post the results after.

[Davi.p]

Re: Philips 42PFL3606H/58 Not powering on, no power indicator - PSU problem?

change that ic801, it's obviously fault, but check q801 much probably is at.fault too.

[DrOetker]

Re: Philips 42PFL3606H/58 Not powering on, no power indicator - PSU problem?

Update: the TV is fixed!

I was able to purchase a known good used power supply for 37 Euros (43 USD) and now the TV works properly.

The faulty components on the original power supply were IC801 (UBA2071AT) and IC901 (NCP1271). I will try to obtain these two ICs and change them using soldering paste and heath gun. I'll report it once the original PSU is also fixed.

Thank you all for your help!

[dick_barton]

Re: Philips 42PFL3606H/58 Not powering on, no power indicator - PSU problem?

Thanks for the follow up.