samsung hp-t5054 no power

[jose6326]

so i did a search for my issues and nothing came up closely related to the issues i am having

only thing i read was faulty ic's on the upper buffer boards

i am having issues with the psu
i disconnected all of the cables going to the psu
i get nothing close to the voltage readings specified on the sticker for vs or va
all fuses checked good

i did a search for the board on ebay
and there are a few sellers selling repair kits that include 2 mosfets and 4 really small resistors you can barely see
on the sellers page it said these are a common component to fail
but of course i rather get my answers here

so i tested 4 mosfets but i dont know if they are shorted or not

here is are the readings on diode mode

mosfet #1
1-2 = ofl
2-3 = .503
1-3 = .007

mosfet #2
1-2 = ofl
2-3 = .504
1-3 = .007

Mosfet #3
1-2 = ofl
2-3 = .419
1-3 = .036

Mosfet #4
1-2 = ofl
2-3 = .415
1-3 = .036

[jose6326]

Re: samsung hp-t5054 no power

I will post pics of the other boards if needed

I dont think its needed now since I believe the problem is with the psu

If I am wrong let me know and I will post pictures


Thanks

[freakaftr8]

Re: samsung hp-t5054 no power

Tour mosfets don't sound shorted. What happens when only xmain is connected?

[tw2005]

Re: samsung hp-t5054 no power

From what you listed they are shorted. common issue with these is the solder fractures on the fets and I think that is when they blow, often the PSU just clicks on and off and they can blow. Other times depending on heat the TV can fire up and then randomly shutdown.

i've also got the same PSu , which I'm reluctant to fix because the ymain and buffer is also fried, a lot of work but you'll find transistors, maybe resistors but more importantly a bunch of smd diodes underside that will be shorted also need replacement.

this kit from shopjimmy is closer to the mark for what you'll need

http://www.shopjimmy.com/samsung-bn4...repair-kit.htm

[tw2005]

Re: samsung hp-t5054 no power

Tour mosfets don't sound shorted. What happens when only xmain is connected?

oh, I was thinking they were? what about the 0.037 and 0.007 readings on pins 1-3? Is that normal for these?

[freakaftr8]

Re: samsung hp-t5054 no power

Now that I thought about it Im not too sure about the readings between pins 1 and 3. Sounds fishy.

[tw2005]

Re: samsung hp-t5054 no power

Now that I thought about it Im not too sure about the readings between pins 1 and 3. Sounds fishy.

probably need to know in or out of cct?

[tw2005]

Re: samsung hp-t5054 no power

This is a parts list for a samsung 50" PSU I have which I believe is the same as yours, may be worth looking at these parts.

F802 T8AH, 250V
QS801,QS802 FQA18N50
DS801,802 kds184
.( RX867, RX869), (RX862 and RX878). 20ohm (2012)
RX863 and RX868 10kohm (2012)

DX803,DX804 KDS184
RX802, RX803, RX832, RX833 100 (2012)
QX801 and QX802 FQPF11N50

RX804 and RX805 10k ohm (2012)

[jose6326]

Re: samsung hp-t5054 no power

tour mosfets don't sound shorted. What happens when only xmain is connected?

i will reinstall the psu and connect the xmain to see what happens

do you expect anything to happen since the psu is not delivering the necessary voltages to the boards?

[jose6326]

Re: samsung hp-t5054 no power

probably need to know in or out of cct?

I will remove the fets and test out of circuit today

[jose6326]

Re: samsung hp-t5054 no power

From what you listed they are shorted. common issue with these is the solder fractures on the fets and I think that is when they blow, often the PSU just clicks on and off and they can blow. Other times depending on heat the TV can fire up and then randomly shutdown.

i've also got the same PSu , which I'm reluctant to fix because the ymain and buffer is also fried, a lot of work but you'll find transistors, maybe resistors but more importantly a bunch of smd diodes underside that will be shorted also need replacement.

this kit from shopjimmy is closer to the mark for what you'll need

http://www.shopjimmy.com/samsung-bn4...repair-kit.htm

they are out of stock on this repair kit at shopjimmy

how do I find out what each component is so I can try to locate them at digikey?

I shouldn't have an issue with the mosfets but the smd resistors and diodes I will have an issue finding

[tw2005]

Re: samsung hp-t5054 no power

they are out of stock on this repair kit at shopjimmy

how do I find out what each component is so I can try to locate them at digikey?

I shouldn't have an issue with the mosfets but the smd resistors and diodes I will have an issue finding

Ah, post #8

Is the board number the same as the file name. when using the schematic be mindful it covers 42 & 50" so the transistors are different but you have yours to go by.

[jose6326]

Re: samsung hp-t5054 no power

Ah, post #8

Is the board number the same as the file name. when using the schematic be mindful it covers 42 & 50" so the transistors are different but you have yours to go by.

yes the file name and board number is the same



thanks

[jose6326]

Re: samsung hp-t5054 no power

how do I find these parts on digikey?

[ricosavy]

Re: samsung hp-t5054 no power

You need to check your ymain the mosfets on these short out and will usually take out your upper buffer board.

[jose6326]

Re: samsung hp-t5054 no power

Ok I will check those as well

But I still need to find the parts for the psu

[tw2005]

Re: samsung hp-t5054 no power

Ok I will check those as well

But I still need to find the parts for the psu

kds184, use 1ss184

SIHG20N50C-E3-ND,

http://www.digikey.com.au/product-se...ords=FQPF11N50

or try ebay, utsource

[flocko]

Re: samsung hp-t5054 no power

Hi best to check power board with just the mains connected, on the white connector first test for 5v stby, if that is there put ps.on to ground the relay should come in,if it does check all small voltages, then connect the 5v stby to Vs on, this will bring Vs voltage up as well. when checking the four FETs do so with meter set at 200 ohms you will see 11 ohms between pin 1-3 , the rest should be open 1-2 and 2-3 hope this is of some help
Flocko

[jose6326]

Re: samsung hp-t5054 no power

hi best to check power board with just the mains connected, on the white connector first test for 5v stby, if that is there put ps.on to ground the relay should come in,if it does check all small voltages, then connect the 5v stby to vs on, this will bring vs voltage up as well. When checking the four fets do so with meter set at 200 ohms you will see 11 ohms between pin 1-3 , the rest should be open 1-2 and 2-3 hope this is of some help
flocko

i did check the white connectors with all main boards connected

i get nothing close to 5v
i think i need to replace the components on the psu then work my way to the ymain

but i want to order all of the parts i need so i am not making multiple orders and waiting for it to come in
and if i have parts the dont need replacing i dont mind having spare parts

[ricosavy]

Re: samsung hp-t5054 no power

the reading you are saying you have on those components are good they are not shorted the power supply is not working because it is not being turned on.I was helping a friend fix his tvs both same model hpt5054 both would not turn on the upper buffer board shorted out and took out the ymain and the logic board.I would check ymain first check the ones attached to these heat sinks also under number 1 heat sink the is a surface mount mosfet that shorts out part number is B20NK50Z.the two surface mount ones in the circle usually don't short out but i would check them.