Philips 39pfl2608/f7 no power

[1beertap]

Hey Guys, this tv has no power. There is no light on the front indicating no 5v. I tested for P-ON+21V on power supply, there's only 11.63v and on the AMP+13V rail, there's only 6.40v. To me, it seems that this power supply is running at half the voltage. Any ideas?

[tvtimmy]

Re: Philips 39pfl2608/f7 no power

I'm not sure,but I think I read something about some of the diodes on the power supply. Unsolder and pull up a leg and test them all.

[CapLeaker]

Re: Philips 39pfl2608/f7 no power

check the DC voltage on the main filter capacitor. Be careful on the mains circuit!

[1beertap]

Re: Philips 39pfl2608/f7 no power

tvtimmy, all diodes were pulled and tested good except smds on backside.

Capleaker, the main caps read 164.3v across both.

Thanks for the replies.

[R_J]

Re: Philips 39pfl2608/f7 no power

Will this help,or do you already have it?

[budm]

Re: Philips 39pfl2608/f7 no power

Hey Guys, this tv has no power. There is no light on the front indicating no 5v. I tested for P-ON+21V on power supply, there's only 11.63v and on the AMP+13V rail, there's only 6.40v. To me, it seems that this power supply is running at half the voltage. Any ideas?

The PO+21V and the amp+13V are correct Voltage when this in standby mode.
As you can see, there is no standby power supply, the power supply is always running but not at full output Voltage until it gets the PS-ON from the main board.
Right now the power transformer driver circuit in the primary side is working so there is no need to probe anything in the primary side.

[budm]

Re: Philips 39pfl2608/f7 no power

BTW, there should be labels for the connector pins on the bottom side of the board.
There are jumpers with ALL_3.3V, that is your standby Voltage, you should have that Voltage.
There are more than one version of this model as you can see here:
http://www.shopjimmy.com/catalogsear...lips+39pfl2608
I cannot read the numbers as printed on the two white stickers on the power supply to match with pictures of the board as shown at SJ.
The blank PCB of your board is BA31T0F01 02 2.

[1beertap]

Re: Philips 39pfl2608/f7 no power

On pin 8 on main board side of connector CN3601, the ALL_3.3V reads 3.36v. I'm beginning to suspect it's a main board problem.

[budm]

Re: Philips 39pfl2608/f7 no power

What DCV do you have on jumpers:
P-ON-H2
PROTECT3
BL-SW

[1beertap]

Re: Philips 39pfl2608/f7 no power

budm,

I tested these with reference to a chassis ground screw.

P-ON-H2 = 0.0v
PROTECT3 = 0.0v
BL-SW = 0.0v

Thanks.

[budm]

Re: Philips 39pfl2608/f7 no power

budm,

I tested these with reference to a chassis ground screw.

P-ON-H2 = 0.0v
PROTECT3 = 0.0v
BL-SW = 0.0v

Thanks.

So the main board is not sending the command signals, if I remember correctly, if the error signal PROTECT3 (LED backlights error) is LOW then it will lock out the command signals. I need to find the thread on that.

[1beertap]

Re: Philips 39pfl2608/f7 no power

budm,

I believe you're right. Could I apply 3.3v to PROTECT3 to try to force the tv to come on?

[budm]

Re: Philips 39pfl2608/f7 no power

You need to cut the PROTECT3 jumper J258 (the one closest to the connector) that goes back to the connector, do not jump the Voltage to the PROTECTION3 or you will damage the LED driver ICs.

[1beertap]

Re: Philips 39pfl2608/f7 no power

I cut PROTECT3 jumper J258 and the tv did not come on. Also, on one side of the now cut J258 reads 2.4v and the previous test points read P-ON-H2 = 0.0v and BL-SW = 0.0v

[budm]

Re: Philips 39pfl2608/f7 no power

I cut PROTECT3 jumper J258 and the tv did not come on. Also, on one side of the now cut J258 reads 2.4v and the previous test points read P-ON-H2 = 0.0v and BL-SW = 0.0v

So now the main board is seeing the HIGH on the PROTECT3 line but still not sending out the command signals to turn on the power supply and the backlights circuit.
Do you know the history of this TV?

[budm]

Re: Philips 39pfl2608/f7 no power

OK, read pot 40 and on to see how we force on the power supply and the backlight circuits.
https://www.badcaps.net/forum/showth...ROTECT3&page=2

[1beertap]

Re: Philips 39pfl2608/f7 no power

If i have 3.3v for standby, would this still not make the standby led on the front of the TV come on?

[budm]

Re: Philips 39pfl2608/f7 no power

If i have 3.3v for standby, would this still not make the standby led on the front of the TV come on?

You may have more than one problem, that is why I suggested the force on of the power supply/LED driver board to see if they are OK since it can be verified easily, and If you have bad LEDs, that is a big job by itself, and if you also have a main board problem too then I am not sure how much time and money you will want to invest in this TV.

[1beertap]

Re: Philips 39pfl2608/f7 no power

budm,
I will use the post#40 of another thread you mentioned and report back my findings. Thanks for the help.

[1beertap]

Re: Philips 39pfl2608/f7 no power

budm,

The backlights are on a long as I have power plugged in. Using three 1k resistors jumped from 3.3v to BL_SW, BL_ADJ and P-ON-H2. The connector is unplugged from main board. Unlike the other member's thread, PROTECT3 does have 3.1v on it.

I see in the comments you say if the PROTECT 3 signal is OK, then we will need to look at PROTECT 1 signal. What voltage can I expect to see on it?