Sceptre X42BV-Full HD Power Supply

[jeffer76]

I am working on a Sceptre X42BV-FullHD that is not creating secondary voltages on the power supply.(FSP270-4M02 or 3BS0134112GP) I have ordered two power supplies from ebay and both are having the same problem. I am getting the 5v standby voltage and approx. 2 volts at p-on when the power button is pressed, but no 5v or 24v source.(24 measures .57)(12 volts not used)

I am testing this board in the tv with nothing connected to it, but the power cord. Jumpering 5v stby to p-on using resistor to supply around 3v to p-on line. Also tried using external dc supply for p-on. no secondary voltages.
I have two questions. First: Am I testing this board incorrectly? Second: I dont see a relay on this board, so are the 24v and 5v secondaries supposed to be on all the time?

[budm]

Re: Sceptre X42BV-Full HD Power Supply

12V/24V supply section is switched on when PS-ON is present, but for it to function it needs PFC Boosted Voltage (around 400VDC) to function, so when you apply Voltage to the PS-ON pin you need to find out if you do have about 400VDC between the two legs of the main filter first.

[jeffer76]

Re: Sceptre X42BV-Full HD Power Supply

I have 160 volts across the cap. even with p-on voltages applied.

[CapLeaker]

Re: Sceptre X42BV-Full HD Power Supply

Your PFC is not working. No boosted voltage, no 12/24V out the secondary's.

[jeffer76]

Re: Sceptre X42BV-Full HD Power Supply

Any recomendations on what to check next? I have three of these boards with the same problem.

[budm]

Re: Sceptre X42BV-Full HD Power Supply

Bottom left of the board. What is the P/N of that 8-PIN SMD IC5 and another 8-PIN IC (I cannot see the designator for this one) next to it?
https://www.badcaps.net/forum/attach...5&d=1472164214

[jeffer76]

Re: Sceptre X42BV-Full HD Power Supply

IC5 markings:4863G and G0609.

Update: Found C208 had low ESR 33mf 35v. I had replaced all secondary caps, but not the ones on the hot side. Replaced the three smaller caps and power supply is now creating the 5, 12, and 24 volt sources.

[budm]

Re: Sceptre X42BV-Full HD Power Supply

Thanks for the follow-up on the repair, those small caps in the primary are the filter caps for the DC power supply generated by AUX winding Pin 5 and pin 6 of the Standby power supply and rectified D204, that Voltage is used for keeping the STBY circuit running and pa it is also fed through the switched transistor to feed the VCC to run the PFC and the 12V/24V SMPS IC.

[bgsasha]

Re: Sceptre X42BV-Full HD Power Supply

Interested in this thread, as I have the same problem....

Which are the pins for PS on? Thank you in advance.

[budm]

Re: Sceptre X42BV-Full HD Power Supply

Interested in this thread, as I have the same problem....

Which are the pins for PS on? Thank you in advance.

Are we talking about the exact same board?
https://www.badcaps.net/forum/attach...6&d=1472164214
The pins for the connector are labeled.

[bgsasha]

Re: Sceptre X42BV-Full HD Power Supply

Are we talking about the exact same board?
https://www.badcaps.net/forum/attach...6&d=1472164214
The pins for the connector are labeled.

Yes, exact same board.

I am not understanding from the labeling which pins exactly should be shorted in order to turn the Power Supply on... Please excuse the novice question and thank you in advance!!

[budm]

Re: Sceptre X42BV-Full HD Power Supply

You will connect 470 ~1000 Ohms resistor between P-ON pin and the 5VSTBY pin to force on the power supply, but you MUST remove the cable between power supply and the main board FIRST.

[bgsasha]

Re: Sceptre X42BV-Full HD Power Supply

You will connect 470 ~1000 Ohms resistor between P-ON pin and the 5VSTBY pin to force on the power supply, but you MUST remove the cable between power supply and the main board FIRST.

Thank you again.

PS. Pins 1 and 7 of the leftmost connector, correct? Cables are removed just like in the photo, only 120v power to the power supply is connected.

[budm]

Re: Sceptre X42BV-Full HD Power Supply

Thank you again.

PS. Pins 1 and 7 of the leftmost connector, correct? Cables are removed just like in the photo, only 120v power to the power supply is connected.

Correct, I always use resistor in case you accidentally connect the wrong pins together.

[bgsasha]

Re: Sceptre X42BV-Full HD Power Supply

Correct, I always use resistor in case you accidentally connect the wrong pins together.

No +12 or 24 volts when pins are jumpered... This is a used replacement bought off of Ebay.

[budm]

Re: Sceptre X42BV-Full HD Power Supply

No +12 or 24 volts when pins are jumpered... This is a used replacement bought off of Ebay.

That means your replacement is bad.
So the Voltage between the two legs of the main filter cap in the hot side also shows around 160V DC?
Just to be sure you make connection using the resistor, what DC Voltage do you have on P-ON pin with ref. to GND, > 2V DC?

[bgsasha]

Re: Sceptre X42BV-Full HD Power Supply

So the Voltage between the two legs of the main filter cap in the hot side also shows around 160V DC?

Yes

Just to be sure you make connection using the resistor, what DC Voltage do you have on P-ON pin with ref. to GND, > 2V DC?

0V DC

[budm]

Re: Sceptre X42BV-Full HD Power Supply

Yes


0V DC

Well, that means you did not get connection on that 1K resistor between P-ON and the 5VSTBY.
0V = main power supply is OFF.
Can we see as how you connect the resistor?

[bgsasha]

Re: Sceptre X42BV-Full HD Power Supply

I was wrong--voltage of up to 2.7V DC on those pins. That voltage seems to fluctuate between below 2 volts and up to 2.7

[bgsasha]

Re: Sceptre X42BV-Full HD Power Supply

I replaced both the mainboard and the power supply, in order to get the TV to work.