Samsung Samsung UN55D6050TF-Power Supply Pulsing, I think.

[budm]

Re: Samsung Samsung UN55D6050TF-Power Supply Pulsing, I think.

BTW, if you check the BL-ON pin without having the board connected to the main board, is the Voltage on the BL-ON pin steady?
Also test this when the main board is not connected to the power supply board, keep black probe on the chassis, red probe on LED connector CNL802 pin 1 (VF+) which is the anode pin of the first LED string, then power up the board while watching the meter to see how high it jumps up to, it should be over 300VDC.

[Dannyx]

Re: Samsung Samsung UN55D6050TF-Power Supply Pulsing, I think.

btw, if you check the bl-on pin without having the board connected to the main board, is the voltage on the bl-on pin steady

+1

[MAVA]

Re: Samsung Samsung UN55D6050TF-Power Supply Pulsing, I think.

Danny,

All my measurements have been with everything connected...

Budm,

Here is my measurement today at 4PM Pacific Time of Pin 16 with everything connected together. Today pin 16 was 3.3v, yet last night was only 2.06v(on the same voltmeter).

To answer your fluctuation of pin 16(with everything connected together-Today):

Pin 16 reaches 3.3v for about five seconds then drops down to 0.213v for like three-seconds then to 0v for about 0v(long enough to see the 0v reading-few seconds), and then back to 3.3v.

The digital board disconnected:

Pin 16 is at 0.93v for like five seconds then to 1.4v for about two seconds then back to 0.93v

The LED Anode Pin1 with the other meter lead in a screw hole on the chassis. On immediate power plug in with the digital board disconnected. The DC voltage goes to 380vDC in a mater of few seconds. Then takes 10 to 15 seconds to stabilize to 402vDC

Martin

[budm]

Re: Samsung Samsung UN55D6050TF-Power Supply Pulsing, I think.

Danny,

All my measurements have been with everything connected...

Budm,

Here is my measurement today at 4PM Pacific Time of Pin 16 with everything connected together. Today pin 16 was 3.3v, yet last night was only 2.06v(on the same voltmeter).

To answer your fluctuation of pin 16(with everything connected together-Today):

Pin 16 reaches 3.3v for about five seconds then drops down to 0.213v for like three-seconds then to 0v for about 0v(long enough to see the 0v reading-few seconds), and then back to 3.3v.

The digital board disconnected:

Pin 16 is at 0.93v for like five seconds then to 1.4v for about two seconds then back to 0.93v

The LED Anode Pin1 with the other meter lead in a screw hole on the chassis. On immediate power plug in with the digital board disconnected. The DC voltage goes to 380vDC in a mater of few seconds. Then takes 10 to 15 seconds to stabilize to 402vDC

Martin

1) Pin 16 which is the PS-ON pin, so when you test the power supply board by itself, it varies from 0.93 ~ 1.4V, if that is the case then the B13V and B5V should also be going up and down too, is that what you are seeing? You reported steady B13V and B5V so that do not add up.
2) 402VDC on pin 1 of the LED connector means the LED power supply is not seeing the load, if look at the Voltage chart printed on the board, it shows 330V @280mA, right now it is not seeing the load (you have open circuit in the LED string/path some where) that is why the Voltage went up that high. But this is also not making sense because you indicated that PS-ON signal is fluctuating so that LED power supply should not be able to come on since it require the PFC Boosted Voltage to function, that PFC Boosted Voltage will only come on when PS-ON is present.
So there must be measurement errors some where.
3) Do you have LED tester to test the whole LED string?

[MAVA]

Re: Samsung Samsung UN55D6050TF-Power Supply Pulsing, I think.

1) I made those measurements with the digital board connected unless I stated disconnected from the digital board, and everything else connected too. I will measure the 13v and 5v with the digital board NOT connected.

2 & 3) I do have TV backlight LED tester, and I have the high voltage version not the original 250v version mine is puts out 360v. I just tested each strip from the connector, and they light up independently, and I can see it load and bright from the 1/2" peep-holes on the metal chassis to see the light. The connector was lock-in too on power supply.

[budm]

Re: Samsung Samsung UN55D6050TF-Power Supply Pulsing, I think.

1) I made those measurements with the digital board connected, and everything else connected too. I will measure the 13v and 5v with the digital board NOT connected.

2 & 3) I do have TV backlight LED tester, and I have the high voltage version not the original 250v version mine is puts out 360v. I just tested each strip from the connector, and they light up independently, and I can see it load and bright from the 1/2" peep-holes on the metal chassis to see the light. The connector was lock-in too on power supply.

But in your post #23:
"The digital board disconnected:
Pin 16 is at 0.93v for like five seconds then to 1.4v for about two seconds then back to 0.93v"
So I am confused as to what is real what is not real.

LED: You need to test it as the whole string, which mean you need to put the jumpers on the female connector so all the LED strips are all connected in series, that is how the male pins on the LED connector of the main board does, it puts all the LED string in series to from one large LED string. You can look at the bottom side of the board and see how each pin of the LED connector pins are tied together.
What does the LED Volt meter on the tester shows for each LED strings?

[MAVA]

Re: Samsung Samsung UN55D6050TF-Power Supply Pulsing, I think.

I originally I had asked for a way to place in order the Mylars, but I did not get a reply, but did mention the screen started to spark after I assembled and plugged everything up, so I put the TV aside, but the set worked well while it was sparking. I let it run for 1minute, but the next day it would not turn. I left the TV set alone, and here we are now.

https://www.badcaps.net/forum/showthread.php?t=75972

[MAVA]

Re: Samsung Samsung UN55D6050TF-Power Supply Pulsing, I think.

But in your post #24:
"The digital board disconnected:
Pin 16 is at 0.93v for like five seconds then to 1.4v for about two seconds then back to 0.93v"
So I am confused as to what is real what is not real.

This is TRUE. The Digital Board was disconnected !!

LED: You need to test it as the whole string, which mean you need to put the jumpers on the female connector so all the LED strips are all connected in series, that is how the male pins on the LED connector of the main board does, it puts all the LED string in series to from one large LED string. You can look at the bottom side of the board and see how each pin of the LED connector pins are tied together.
What does the LED Volt meter on the tester shows for each LED strings?

Individually they light up fine, but in series I get nothing I can see, nor will the back light register anything on the tester. Yet the TV set worked with these LED strips.

I have not done any board work the power supply board, but maybe the 100 individual LED's have a higher bias voltage than the other strip. Well I guess it does. The right strip I get 142vDC. The left strip I get 294vDC...

Can I just forget about the LED strips and hang resisters to simulate the load, so the power supply is balanced, and it see's a load as the digital board pulses?

[budm]

Re: Samsung Samsung UN55D6050TF-Power Supply Pulsing, I think.

"The right strip I get 142vDC. The left strip I get 294vDC." Did you use 6V LEDs instead of 3V LED's or you got wrong strip on the one that shows 294V?
The LED strips are connected in series so 142V + 294V = 436V @30mA so no way the LED driver will light that whole string up.

[MAVA]

Re: Samsung Samsung UN55D6050TF-Power Supply Pulsing, I think.

Budm,

By result it sure is it, but their is 100 LED's per side, and I hand soldered all 100 LED's with a heat gun and paste flux

I had found a link for a pair of new LED strips for this TV for $50 or so. I need to find that link as the fleabayers want too much for just one stip. Have any links on cheap LED Strips??

Martin

[budm]

Re: Samsung Samsung UN55D6050TF-Power Supply Pulsing, I think.

https://www.shopjimmy.com/catalogsea...sung+UN55D6050
You need to get the correct strip to match the LCD panel model number.
BTW, each strip of LED has 100 LEDS, they are divided into two sub strips with 50 LEDs each and then they connect the two sub strips in parallel to form 1 LED strips. so the one that shows 294V you probAbly put in 6V LED's instead of 3V, they can easily be verified with LED tester.
BTW, did you inspect the wires from the LED connector of the power supply all the way to the LED strips to make sure none of them were nicked and exposed the wire conductor that may have shorted to the chassis since you indicated in post #1 that you heard the popping sound.

[MAVA]

Re: Samsung Samsung UN55D6050TF-Power Supply Pulsing, I think.

Thank you for the help, but it may be a few weeks before I get to it, and I will continue to post.

Thank you,

Martin

[budm]

Re: Samsung Samsung UN55D6050TF-Power Supply Pulsing, I think.

Should not be hard to test the LEDs that you use for the repair, I am sure you would have some left over that can be tested with the LED tester to find out what the Vf is.

[MAVA]

Re: Samsung Samsung UN55D6050TF-Power Supply Pulsing, I think.

Finally fixed the TV, and it was the light strip. I bought some Chinese replacements light strips. I got them in three-weeks from Aliexpress. Paid like $23 out the door for the pair, and replaced both of them.

https://www.aliexpress.com/item/4000...76f84c4dJ6Y267

I noticed the replacements had a thin layer of double-sticky tape, so they isolate them thermally from the main aluminum chassis(Bad Bad Bad Move... So they burn-out faster). I removed the double-sticky tape. Cleaned the aluminum LED strip back surface with Acetone. I even applied a layer of a very transparent layer of American Made Thermal Grease Compound. Applied a transparent layer to the chassis too, so the heat can conduct...

TV is working great...

Ohh measured/tested the replacements with Strip-LED-Tester, and on each replacement I got 144v, and all 100 LEDs lit up well..

Thank you everyone for your help..

Martin

[budm]

Re: Samsung Samsung UN55D6050TF-Power Supply Pulsing, I think.

Make sure to turn down the backlights on all input mode as low as possible to extend the life of the LED's.

[MAVA]

Re: Samsung Samsung UN55D6050TF-Power Supply Pulsing, I think.

Oh yea, did that right away too...

Thank you Budm...