Philips 37PFL4606 No Power

[trunks81]

Hello

Iam new to this forum an got an question right away !

Ive got this powersupply and it is not powering on
The standby led on the chasis is on and when powering on it goes off and then 5 secs later its back.
Also the blue led on the back off the power supply goes on and then fades away.
Iam measuring on the + and - on the rectifier 313V ! on C907 iam getting the same 313V.
On CN903 iam getting +5V even when connecting S/B to +5V iam only getting +5V so no 12v/24V

What did i miss ?

[dick_barton]

Re: Philips 37PFL4606 No Power

Disconnect the mainboard from the power supply and connect a 1K resistor between 5V and S/B pin then check you have 12V and 24V supply.

[budm]

Re: Philips 37PFL4606 No Power

Can we see good clear pictures of what we are dealing with?

[trunks81]

Re: Philips 37PFL4606 No Power

Hello, i cant test at the moment because i dont have an 1k resistor.. its on the way
also i attached the photo's from the power supply i more pictures needed let me know

[trunks81]

Re: Philips 37PFL4606 No Power

Oke Finally got the resistor.. And connected S/B To 5V
And i dont see 12V or 24V iam getting 0V
Only got the 5V

[dick_barton]

Re: Philips 37PFL4606 No Power

The circuit diagram may be similar but it's not your power supply.
If you look at the labels alongside the pins on the underneath of the psu board ( CN903 ) then you can see that you have the wrong pins connected.
It should be Pin 11 or 12 (+5V) connected to pin 10 (S/B) using the 1K resistor

[trunks81]

Re: Philips 37PFL4606 No Power

Hello

This is on the power supply

[dick_barton]

Re: Philips 37PFL4606 No Power

OK it looks like one end of that connector is 14 pin and the other end where you have placed the resistor 13 pins which is what confused me.
With the mainboard still disconnect and the 1K resistor connected what is the DC voltage between the two legs of C907. The woltage will be around 330 - 385V dc so measure carefully

[petehall347]

Re: Philips 37PFL4606 No Power

might be wrong but it looks like to me that its been worked on before

[trunks81]

Re: Philips 37PFL4606 No Power

Hello

Between the legs of C907 iam getting 309VDC,

Edit is allready replaced D901,Q902 and R919 because board whas doing notting in the begining

[budm]

Re: Philips 37PFL4606 No Power

715G4546-P02-H20-003 power supply Schematic and PCB.
OP post #10 "Between the legs of C907 i am getting 309VDC"

1) Is your AC line Voltage 230VAC? If it is when the pull-up resistor is not in place the Voltage on the cap should be around 325VDC, and when PS-ON is present it should jump up to 395VDC.
2) You need to check the DCV on S/B pin right at the power supply connector to see what you get.
3) If the S/B pin does show more then 2VDC, the unpower the board and check the PFC Diode D901 in diode mode and resistance mode.
4) If number 3 checked OK then verify that IC902 VCC pin 8 to see if it has Voltage to run it, you must use the negative leg of the main filter cap C907 as the ground ref for the hot side of the circuit, be real careful you are working in the deadly side of the circuit.
5) I do not know why the schematic you post does not show the values or designators of the components.

[trunks81]

Re: Philips 37PFL4606 No Power

Measured S/B pin to ground and iam getting 0V
On IC902 pin 8 to ground of Filter cap C907 iam getting only 9.8V, when S/B is connected to 5V when not its 0.34V
D901 its 2.5kohm and reverse OL

[budm]

Re: Philips 37PFL4606 No Power

Measured S/B pin to ground and iam getting 0V
On IC902 pin 8 to ground of Filter cap C907 iam getting only 9.8V, when S/B is connected to 5V when not its 0.34V
D901 its 2.5kohm and reverse OL

You need to recheck how you have that /SB connected to 5V, it should not be 0V if it is connected correctly.

[trunks81]

Re: Philips 37PFL4606 No Power

Hello

Sorry did not connect S/B to 5V when measuring,
But when measuring S/B to GND now iam getting 4.98V

[dick_barton]

Re: Philips 37PFL4606 No Power

You say you are getting 9.8V on IC902 Pin 8 (VCC). This is too low to operate the IC which needs a minimum of 11.5V. Check the voltages on the three legs of Q907

[trunks81]

Re: Philips 37PFL4606 No Power

You say you are getting 9.8V on IC902 Pin 8 (VCC). This is too low to operate the IC which needs a minimum of 11.5V. Check the voltages on the three legs of Q907

Iam getting on all three legs 9.8V

[dick_barton]

Re: Philips 37PFL4606 No Power

This is with the mainboard disconnected from the power supply and the 1K resistor still in place?

[trunks81]

Re: Philips 37PFL4606 No Power

Hello

Mainboard is disconnected from power supply and 1k is stil in place

[dick_barton]

Re: Philips 37PFL4606 No Power

9.8V is too low to run IC902 which requires a minimum of 11.5V to operate according to its datasheet.

Can you receck the voltage at the junction of D915/C946 junction. Use the negative leg of C907 as ground.

[trunks81]

Re: Philips 37PFL4606 No Power

Hi am getting the next values..

On the + of D915 to ground of C907 = 322,4V
On the + of C946 to ground of C907 = 9.85V