Samsung PN59D550 Led flashes and wont turn on!

[frappim]

Hello, my friend was throwing out their 3D Samsung plasma TV because it just stopped working one night.
So I thought I'd grab it and try and fix it. I was hoping it was just a bad cap, but they all look fine
So, I'm here now, asking for help from you experienced people.
I am in my second year at college taking an electrical program, so I know how to solder pretty good, and I understand electronics atleast a little bit
I also have access to a multimeter!

So, when I first plug the TV into the wall, you hear the relay click and you see static on the TV for about 1 second and then it turns off and the LED flashes 4 or 5 times.
When I open up the case, you can see on the back on one of the PCB's that there is a green LED that flashes. Don't know if it means anything. but it must!

If you need any more information or pictures please feel free to ask!

The board that the main power connects to looks a little burnt at the top. but all the solder connections look OK, is this a problem?

[ReeceyBurger123]

Re: Samsung PN59D550 Led flashes and wont turn on!

So does the Tv come on with the X and Y sustains disconnected ?

[frappim]

Re: Samsung PN59D550 Led flashes and wont turn on!

Would that be the ribbon cable at the top of the main power PCB? if you look at the second picture I uploaded, you can see a nice overview of how things are connected
I disconnected the top ribbon cable from the middle board and the same thing happens, which is nothing.
I don't know the name of the boards, so I'm just really guessing what they all are at this point!

[frappim]

Re: Samsung PN59D550 Led flashes and wont turn on!

Okay so I did a little more research. Unplugging the X board doesn't have an effect, but I cannot directly unplug the Y board because the X sustain is plugged though Y. Unplugging them both makes the TV do nothing. I'm thinking maybe it's a logic control board failure?
Any way I can test which board is the culprit?

[bman4]

Re: Samsung PN59D550 Led flashes and wont turn on!

first check power supply voltages while tv is off but plugged in.

is there stand by voltage 5.4v?

is there a ps on voltage 3.3v?

next check voltages while powering on the set.

dose the ps on voltage drop to 0 as you turn the tv on?

dose the vs on voltage rise as you turn the tv on to 3.3.

if the vs on voltage dose not rise as you turn the tv on suspect a defective logic board.

next check your high voltage vs and va points.

dose it intermittently show voltages that match your panel sticker while powering on,if yes your power supply is good.

dose your logic board led blink with a long 5 sec pause while illuminated?

if so something is wrong with your buffers ,y main or x main.

next step i recommend is testing your buffers.

if buffers test good next y main then x main.

[frappim]

Re: Samsung PN59D550 Led flashes and wont turn on!

So where would I test for these voltages? The only board I see with test points is the power board /: I don't see any place to test voltages on any of the other ones

[Alastair E]

Re: Samsung PN59D550 Led flashes and wont turn on!

So where would I test for these voltages? The only board I see with test points is the power board /: I don't see any place to test voltages on any of the other ones

Hmm--

Hava a guess where you test them then!

[frappim]

Re: Samsung PN59D550 Led flashes and wont turn on!

next check voltages while powering on the set.

dose the ps on voltage drop to 0 as you turn the tv on?

dose the vs on voltage rise as you turn the tv on to 3.3.

Well apart from not knowing where to actually put my multimeter to test each board, does it mean anything if I say that pushing the power button on the TV doesn't even turn it on? I can spam the power button and sometimes a few minutes later you hear it click on and off once. The only time I can really get it to turn on when I want is when I first plug it into the wall.
I'd just like to know where to test for all these voltages! ):

[bman4]

Re: Samsung PN59D550 Led flashes and wont turn on!

put your black probe on the chassis and look for those various labels on your power supply.

list the labels and voltages on here when your tv is plugged in and off.

next the voltages while you hear the chime as you turn on.

dose your logic board led blink with a long 5 sec pause while illuminated?

that led you seen blinking in side is the logic board.

if your led is blinking your tv has turned on.

might be a little slow but give it some time to chime.

you symptoms sounds like main or psu.

you will want to test after first plug in and power on and repeat if that's the only way to get tv to turn on.

[frappim]

Re: Samsung PN59D550 Led flashes and wont turn on!

list the labels and voltages on here when your tv is plugged in and off.

next the voltages while you hear the chime as you turn on.

dose your logic board led blink with a long 5 sec pause while illuminated?

if your led is blinking your tv has turned on.

might be a little slow but give it some time to chime.

okay so green LED on the logic board flashes 5 seconds on, 2-ish seconds off.
Upon initial plug-in of the TV,

There is no chime when turning on the TV. It can be on for 30 minutes and it won't chime.

VS goes to around 218 volts then drops down and stops at 10V.
VA goes to around 55 volts then drops down and stops at 0V.

by the main board, are you taking about the logic board or the board with all the input connections on it?

[bman4]

Re: Samsung PN59D550 Led flashes and wont turn on!

okay so green LED on the logic board flashes 5 seconds on, 2-ish seconds off.
Upon initial plug-in of the TV,

There is no chime when turning on the TV. It can be on for 30 minutes and it won't chime.

VS goes to around 218 volts then drops down and stops at 10V.
VA goes to around 55 volts then drops down and stops at 0V.

by the main board, are you taking about the logic board or the board with all the input connections on it?

okay your power supply voltages are good for the vs &va


what about vson,pson standby?

it just a more serious fault so it shuts down before it can chime.

im guessing everything is working because you logic boar led is on and your vs and va voltage is intermittent.

your led indicates that there is something wrong with you panel drivers or buffer's ,y&x main.

next would be to check the buffers.

then if your buffer are good replace x&y main

[frappim]

Re: Samsung PN59D550 Led flashes and wont turn on!

okay your power supply voltages are good for the vs &va

what about vson,pson standby?

next would be to check the buffers.

then if your buffer are good replace x&y main

where do I find the vson and pson, which board?
and are there test points on x&y buffer and main boards? how do I go about testing those?
I'll look for vson and pson, and if I find them I will report them!
Thanks for helping!

[sordids999]

Re: Samsung PN59D550 Led flashes and wont turn on!

Does the panel glow when the tv turns on ?

[frappim]

Re: Samsung PN59D550 Led flashes and wont turn on!

Does the panel glow when the tv turns on ?

Nope. it turns on for about 100 ms then turns off.
I do see fuzzy static in the small amount of time it's on though.
if you read my previous posts, what would you think it might be? I'm no plasmaTV expert, so I have no idea what it could be :/

[sordids999]

Re: Samsung PN59D550 Led flashes and wont turn on!

ok have u tested the buffer boards like this ?

https://www.youtube.com/watch?v=51SZsfH60EY

Vsc reading will be on the Ysus board
Ve reading will be on the Xsus board

[frappim]

Re: Samsung PN59D550 Led flashes and wont turn on!

Does this TV (PN59D550) have a protective glass, pr protective anything infront of the plasma screen?

[frappim]

Re: Samsung PN59D550 Led flashes and wont turn on!

ok have u tested the buffer boards like this ?

https://www.youtube.com/watch?v=51SZsfH60EY

Vsc reading will be on the Ysus board
Ve reading will be on the Xsus board

on standby the X-sus board here are the reading from the test points I see:
SVC_XOUT = 9.1V
VB = 5.6V
SVC_VS = 10V

On the Y-sus board on standby:
SVC_YOUT = 0V
Vsch = 0.1V
SVC_VS = 10V
Vscan = 0v

Everything has some sort of voltage when I can get it to power on for the couple of seconds, but it doesnt stay on long enough for me to get an accurate reading.
If you really need the numbers I can plug and unplug like 10 times for every test point to get a reading!
are these normal values for standby?

[frappim]

Re: Samsung PN59D550 Led flashes and wont turn on!

Could this possibly be a reason it doesn't work? just noticed it today!
Is there a possibility that it just cracked on the surface and the display still works fine?
Because the TV stopped working while my friend was watching it, it had nothing to do with this crack! this must of happened after. :/

[frappim]

Re: Samsung PN59D550 Led flashes and wont turn on!

Oops I double posted and I cant find the delete button

[Alastair E]

Re: Samsung PN59D550 Led flashes and wont turn on!

OOops--Thats the end of it!