Samsung 245bw No Power No LED

[selldoor]

Re: Samsung 245bw No Power No LED

Seems ok, good, can you connect all the boards up and plug in but do not press power.
On the top right of the power supply is a connector with 24v mentioned.
Set your meter on 200VDC and put the black probe on a ground screw and test each pin
on the connector with the red pin- Do not touch any heatsinks. record results
Pin Designation Actual
1 24v 24.2v
2 24v 24.2v
3 ? 1.79v and so on

Then press the power button and do it again. Only bother to record results if diffferent.

[Ober]

Re: Samsung 245bw No Power No LED

Again i have the question of, do i need the LCD itself plugged in too? that makes it really difficult to work on so just wasnt sure, sorry if it seems a stupid question cause you did say connect all boards but checkin reguardless... once both the top and sides to the screen itself are connected everything is kinda stuck together and small workin area...

[selldoor]

Re: Samsung 245bw No Power No LED

You do really because what happens is when the panel is not connected it registers as a fault and the protection circuits kick in and shut the power supply down, although for some tests we will ask you to unplug a board.

It also has the bonus of if it is just a cold joint causing the problem it may
just start to work out of the blue.
Some people have been able to work by stacking the boards and separating them with sheets of cardboard.

[Ober]

Re: Samsung 245bw No Power No LED

i had to take the other board inside the metal backing out to get it connected where i could even see the power board, but now i have the worry of not being sure if the screws are needed for ground? do i have to do something to fix that issue?

Also just realized your test includes the ground screw, how exactly are you doing this Through the metal backing?

[selldoor]

Re: Samsung 245bw No Power No LED

Try it without for now if the results are not as expected you can wire the gound screw holes on the boards together.

[Ober]

Re: Samsung 245bw No Power No LED

So i cant cause damage havin it plugged in without ground screws in? why do they bother with ground screws then? heh seems like im missing somethin here..

[Ober]

Re: Samsung 245bw No Power No LED

Are you talking about 24v pins from a ribbon cable going into power board from the board that connects to the LCD? (thats the only thing ive identified as 24v so far but after pluggin everythin in im havin trouble seeing it all)

[Ober]

Re: Samsung 245bw No Power No LED

Used LCD ground screw, hoping it would work...

Without power switch to on.. All of them showed 0.01 and 0.00 when not touching
Power switch on, they all showed 24.2

Also looked at the front LED just curious and no LED still, so no miracle luck :P

[selldoor]

Re: Samsung 245bw No Power No LED

All of them? you should be getting what the board description says.
I wish you would list the results of tests like I am asking you.

Now test the large connector on the opposite end of the board meter on 200vdc use probes as previous- can you spot a pin with pwr or on/off or pson.

Do it twice as before first power off then power on. Remember even when its off the big cap has 400v and heatsinks may still give a nasty jolt.

[Ober]

Re: Samsung 245bw No Power No LED

I apologize for my formatting, when i looked at this previously i missed part of it and saw 1 24v 24v and was just a lil confused what you meant by it, just realized that was the pin#/label/reading..
Pin Designation Actual
1 24v 24.2v
2 24v 24.2v
3 ? 1.79v and so on

Ill do the test again and test ALL of the pins.. i thought you just meant the 24v ones.. then im happy to have the next step already so i can continue after postin results of first test :P thx..

[Ober]

Re: Samsung 245bw No Power No LED

1 24v 24.2
2 ""
3 ""
4 ""
5 ""
6 Ground 0.0
7 ""
8 ""
9 ""
10 ""
11 SOS 0.0
12 BL 3.5
13 A_Dim 0.0
14 ST_Dim 0.0


Then i tried to test again, suddenly the monitor came on and the 11-14 tests all showed readings (door rang, turned it off before i got readings written down) and tried again and it didnt turn on... (by turn on i mean i saw the white backlights shine through from the LCD - not sure what it showed or anything cause its face down..

[Ober]

Re: Samsung 245bw No Power No LED

ive tried to replug it in and turn on a few times hoping for that miraculous fix where it turns on, but i hear the sound as if its turning on but nothing happening... similar to the first time i tested... still wondering why i randomly got a workin switch then cant reproduce heh... grrrr...

[selldoor]

Re: Samsung 245bw No Power No LED

Good - that is encouraging - could be a loose pin or joint or a cap that starts working better when it gets warm. I have a busy day tomorrow so early night. Do the rest of the test again and if it comes on try to record exactly what you were doing.

[Ober]

Re: Samsung 245bw No Power No LED

11 SOS 0.0
12 BL 3.5

I Had those reading backwords.... SOS was 3.5 and BL was 0.0 (when the backlights didnt come on)

[Ober]

Re: Samsung 245bw No Power No LED

Same reading over and over -- Cant get it to reproduce the backlights commin on either... tried several plug/unplug and switch on/off attempts..

1 24v 24.2
2 ""
3 ""
4 ""
5 ""
6 Ground 0.0
7 ""
8 ""
9 ""
10 ""
11 SOS 3.5
12 BL 0.0
13 A_Dim 0.0
14 ST_Dim 0.0

[Ober]

Re: Samsung 245bw No Power No LED

spotted PSON on board...
Doing tests on the opposite cable,

Tested with power off, got nothing, plugged in and got the miraculous backlight shine!

So i tested both sides while on...
First ribbon cable you asked about with power/backlights on...
1 24v 24.2
2 ""
3 ""
4 ""
5 ""
6 Ground 0.0
7 ""
8 ""
9 ""
10 ""
11 SOS 0.2
12 BL 4.7
13 A_Dim 5.1
14 ST_Dim 5.2

2nd Ribbon cable on other side of board with power off all were 0,
with power/backlight on these were the results..

1 PSON 1.8
2 SB 5
3 GND 0
4 GND 0
5 GND 0
6 NC 0
7 NC 0
8 NC 0
9 GND 0
10 GND 0
11 GND 0
12 5.2 5.2
13 5.2 5.2
14 5.2 5.2
15 NC 0
16 NC 0

then there was another small cable next to, wish i had tested it while i was on, roomate walked in and distracted so im back to not reproducing the backlights so until i get lucky again wont know about that cable, but you never asked about that cable either..

[selldoor]

Re: Samsung 245bw No Power No LED

then there was another small cable next to, wish i had tested it while i was on, roomate walked in and distracted so im back to not reproducing the backlights so until i get lucky again wont know about that cable, but you never asked about that cable either..

I am trying to keep it simple and I dont know what the small cable is
lead from power switch?
Anyway - Test it as the others.



Going back to the PSON pin (you might need a helper for this.) You have to do the test again but you need to have the meter on the pin and groundand observe the voltage (should be nil according to previous measurement) then you need to press the power button and report what the voltage does on the PSON pin. If you can firmly anchor the black probe and reach the button whilst touching the pin with the red probe you may be able to do it yourself.

The two caps you say are bulged are they in a group of 4 behind the
large and small connector and can you confirm the uf.and voltage.

[Ober]

Re: Samsung 245bw No Power No LED

yes, group of 4 capacitors, 2 are 10v 200uf the other 2 that had the slight bulge were 10v 1000uf

[Ober]

Re: Samsung 245bw No Power No LED

PSON goes from 0 quickly up to 2.6 then drops back down to 0 sometimes, other times it will go from 0 quickly up to 2.6ish and then raise slowly, i got to 3.0 - moved on to test other things and came back to it and it was up to 4.0 so it slowly gains and slower the higher... (the drop to 0 COULD be me not gettin a good reading, ive tried so many times and sometimes it doesnt reproduce the same results, several times in a row its either not worked atall or gone up to 2.6 and counting +0.1 from there.. really slowly once it reaches 4.0 not sure how far it would go cause i started to cramp up each time around 4.0 hehe


that extra smaller cable was the rest of the PSON line
No Power
BL 0
SOS 0
A_DIM 0
PS/T_DIM 0
DBT 0

With Power
i got 2 readings, one in the 2-3 range and one i think ~5.2 but when i went back to test again i havent gotten it to give readings, whatever is stoppin the LCD commin on is also stoppin the readings.. cause when it comes on i get almost everythign to read something
--Still tryin once in awhile hoping to get those reading again, will post when seen..

Power On
BL 0
SOS 3.5
A_DIM 0
PS/T_DIM 0
DBT 5.2

[selldoor]

Re: Samsung 245bw No Power No LED

yes, group of 4 capacitors, 2 are 10v 200uf the other 2 that had the slight bulge were 10v 1000uf

Yes I thought so - that is not what you said in post 6.


Are you sure they are 200uF no-one else seems to have those

Do you have a 1kohm resistor.

What 50v caps can you see in the primary (HOT) side of the power supply.
I mean what uF values are there.

I think someone asked you to make a list of all the caps on the board
did you do that?

How are your soldering skills.


Have you got a hair dryer