LCD Philips 47PFL4606H/12 - power supply doesn't start, no voltages

[Folxs]

Hi, I have LCD TV Philips 47PFL4606H/12 - there are any voltages on power supply.
I chcecked fuse and it is OK, bridge rectifier (there are 330V DC), diodes, transistors and everything is ok - why PSU doesn't start at all? Maybe driver to produce voltages is bad? How to check that IC?

Whole system drives 0.8W from wall adapter


PSU board: 715G4546-P03-H20-003U

[attainteddragon]

Re: LCD Philips 47PFL4606H/12 - power supply doesn't start, no voltages

on cn 903 (14 pic connector that runs from the p/s to the main board), can you let us know what voltages you have on every pin in stby and when the power button is pressed.


eg
pin no. desc. stby v. on v.
1 ena 0.00 0.12
2 dim 0.00 0.34
3 12v 0.00 4.27
4 12v 0.00 4.27
5 gnd 0.00 0.00
etc, etc

[dick_barton]

Re: LCD Philips 47PFL4606H/12 - power supply doesn't start, no voltages

What are the voltages at the connector?

[Folxs]

Re: LCD Philips 47PFL4606H/12 - power supply doesn't start, no voltages

on cn 903 (14 pic connector that runs from the p/s to the main board), can you let us know what voltages you have on every pin in stby and when the power button is pressed.


eg
pin no. desc. stby v. on v.
1 ena 0.00 0.12
2 dim 0.00 0.34
3 12v 0.00 4.27
4 12v 0.00 4.27
5 gnd 0.00 0.00
etc, etc

On every pin are exactly 0.00V - so I think it isn't even in standby mode, also pressing button makes nothing change (there are touch panel, so I guess it isn't working at all because there aren't any voltage)

[dick_barton]

Re: LCD Philips 47PFL4606H/12 - power supply doesn't start, no voltages

Check the fuse and also what is the DC voltage across the two legs of the large capacitor.

[Folxs]

Re: LCD Philips 47PFL4606H/12 - power supply doesn't start, no voltages

Check the fuse and also what is the DC voltage across the two legs of the large capacitor.

Fuse OK, 330V on big filter capacitor

There are transformer (with sharpy I made where goes windings)
On primary there are 330V both sides of windings
On secondary on one side is " - " and nothing is going on.

This is connected to IC902 that is PFC controller FAN6961

[dick_barton]

Re: LCD Philips 47PFL4606H/12 - power supply doesn't start, no voltages

What voltage do you have on the FAN6961 between pin 8 and pin 6 when you switch on out of standby.

With the set off what is the resistance of R919 and what part numbers are the two mosfets.

What has happened to IC905 and what is the part number

[Folxs]

Re: LCD Philips 47PFL4606H/12 - power supply doesn't start, no voltages

What voltage do you have on the FAN6961 between pin 8 and pin 6 when you switch on out of standby.

With the set off what is the resistance of R919 and what part numbers are the two mosfets.

What has happened to IC905 and what is the part number

1.

when you switch on out of standby.

I can't - because standby need to have standby volatage to power standby mode

2.

What voltage do you have on the FAN6961 between pin 8 and pin 6

0.4V but in dead mode

3.

With the set off what is the resistance of R919

0.33 Ohm - measured 0.4 so it's fine (I have pretty crappy DMM)

4.

what part numbers are the two mosfets.

Left one is Diode D901 - STTH5L06FP (Turbo 2 ultrafast high voltage rectifier) (Datasheet: https://cdn.badcaps-static.com/pdfs/...6525d4fea4.pdf )
On the right we have TF10N60 ( 600V, 10A N-Channel MOSFET)
(Dataseet: )

5.

What has happened to IC905 and what is the part number

This is original looking chip. TOP264VG (Integrated Off-Line Switcher with EcoSmart™ Technology
for Highly Efficient Power Supplies)
(Dataseet: https://cdn.badcaps-static.com/pdfs/...d132290b22.pdf )

[dick_barton]

Re: LCD Philips 47PFL4606H/12 - power supply doesn't start, no voltages

I suspect the TOP264VG IC or circuitry around it is at fault because that supplies the +5V voltage. See page 54 of the attached manual

[budm]

Re: LCD Philips 47PFL4606H/12 - power supply doesn't start, no voltages

https://www.badcaps.net/forum/attach...0&d=1530882538
Try heating up or replace the two startup/running caps C943, 946 in the STBY power supply section. you should also check the Voltage right between the two legs of C943, 946 but you have to be really careful since they are in the hot deadly side of the circuit. You can test the power supply board by itself without having it connected to the other board, we just have to get the STBY power supply section working first.
Did you already check the rectifier diode on the heatsink to the right of the transformer T904 on the cold side of the STBY power supply?
BTW, did some one work on that power supply board before? It looks like there used to be heatsink on top of that IC905.

[Folxs]

Re: LCD Philips 47PFL4606H/12 - power supply doesn't start, no voltages

I suspect the TOP264VG IC or circuitry around it is at fault because that supplies the +5V voltage. See page 54 of the attached manual

Can I test this IC somehow? Or just replace with new one?

Try heating up or replace the two startup/running caps C943, 946

Didn't helped - I measured them and both have good capacity and ESR

check the Voltage right between the two legs of C943, 946

C943 0.00V
C946 - when I plug TV to wall there are 2.38V and slowly dropping to 0.00V (like a capacitor discharge)

Did you already check the rectifier diode on the heatsink to the right of the transformer T904 on the cold side of the STBY power supply?

Yes, it is double diode D917 - both diodes are good

BTW, did some one work on that power supply board before? It looks like there used to be heatsink on top of that IC905.

I don't know, but i don't think so - there were no signs of even opening TV before me

[dick_barton]

Re: LCD Philips 47PFL4606H/12 - power supply doesn't start, no voltages

I don't know, but i don't think so - there were no signs of even opening TV before me

This is an open top IC connected to the internal mosfet source connection.

[Folxs]

Re: LCD Philips 47PFL4606H/12 - power supply doesn't start, no voltages

This is an open top IC connected to the internal mosfet source connection.

I know that this is open top IC - but I don't understand second half of Your post (sorry about my english)

[Folxs]

Re: LCD Philips 47PFL4606H/12 - power supply doesn't start, no voltages

One more question - what is IC801 (UBA2071AT) on the bottom of PSU, this is for backlight?

And question about IC905 - it would start by itself, of something have to power that chip on first?

[dick_barton]

Re: LCD Philips 47PFL4606H/12 - power supply doesn't start, no voltages

It looks like it's a PWM to provide the 12V & 24V supplies. I believe it gets its voltage from T904 through R959, D916 & Q907 (which is switched on via the standby voltage).

[Folxs]

Re: LCD Philips 47PFL4606H/12 - power supply doesn't start, no voltages

Ok, so first chip to create anything is IC905? TOP264

[Frankcal]

Re: LCD Philips 47PFL4606H/12 - power supply doesn't start, no voltages

It looks like it's a PWM to provide the 12V & 24V supplies. I believe it gets its voltage from T904 through R959, D916 & Q907 (which is switched on via the standby voltage).

Hi,
Just signed up to day, have being following this line as I have exactly the same issue, same power board, only live voltage is 330v. No 5v or 12 or 24 v. Did you find the problem on yours, it may help me also?

Frank

[Folxs]

Re: LCD Philips 47PFL4606H/12 - power supply doesn't start, no voltages

Did you find the problem on yours, it may help me also?

Frank

No I didn't - can't help You, sorry

[R_J]

Re: LCD Philips 47PFL4606H/12 - power supply doesn't start, no voltages

The first section to get working is the standby, You need +5VSB, Using [-] of C907 for ground (HOT GROUND) Check the voltage on pin 6 of ic905 (use anode of D915), then check the voltage on pin 1 (anode of ZD908) and pin #3 (zd907 cathode)
Also check the voltage across ZD909, If it is 0 volts, check if the zener is shorted

It is very likely that IC905 is defective if you don't have standby voltage

[Frankcal]

Re: LCD Philips 47PFL4606H/12 - power supply doesn't start, no voltages

Hello, My name is Frank living in Galway Ireland.
I have carried out the following checks on the powerboard removed from the tv & powered up on the bench. The hot side has 313v. But no 24, 12 or 5v on the low side.
Using - on c7 as ground, i have measured the following on ic 105, p6 = 313v, p1= 1.6v, p3 = 2.7v. I note the scheematic shows 395v on the hot side, however I only get 313v ??
I have already replaced ic 905. V across zd909 is 2.75v

Your help is much appreciated
Thanks
Frank