Samsung UHD UN50JU6500

[lfhlaw]

Re: Samsung UHD UN50JU6500

ok Diah wanted some additional pictures. Including complete set up.


as far as BudM's post...i might've tested incorrectly now that I saw the picture posted. As I Was testing it ...like my 2nd picture - only demonstration purpose there.

[nomoresonys]

Re: Samsung UHD UN50JU6500

Ok, those are some swell pictures, did you do the requested tests tho?

[lfhlaw]

Re: Samsung UHD UN50JU6500

OP: Did you test as suggested in my post #14?
Connector CNM803 pin 8 (PWR-ON/PS-ON) has pull-up resistor for self-test function. If the PS-ON is not present, the A13V will be about 8V, when the Main board board is disconnected (PS-ON pin on the main board side has open Collector circuit) from the Main board, the PS-ON will be pull up high which will cause the Voltage at A13V pins to go from 8V to 13V, at the same time the PFC boosted Voltage on the main cap will jump up from 160VDC to about 380 ~ 400VDC.
So What are the Voltages at the CNM803 when main board is NOT connected? The result will tell us which control pins have pull-up resistors or not.

I'm not an electrician, so much of this feels very technical to me so bear with me.

I attempted to test the A13v standby by flipping the PSU board over and unplugging the LED and Main board. However, When I tested the A13V, i didn't get any voltage there or at the PS-ON (where boxed on your pic) when it was plugged into the outlet.

The PS-ON Pull-up resistor showed no voltage either.

[budm]

Re: Samsung UHD UN50JU6500

What did you use for meter ground? If now you do not even have 8V standby Voltage then some thing must have got worst since you did have 13V when all the boards are connected, it is measurement error.
Meter is set correctly?

[lfhlaw]

Re: Samsung UHD UN50JU6500

This TV has all the LED strips connected in series to form 1 large LED string.
Connector CNL802 Pin 1 (2+) is the Anode pin for the #2 LED set, this pin is connected to the Boost converter circuit (puts out 277 or 337 VDC as printed on the board). Pin 4 (2-) which is the Cathode of #2 LED set and it is connected to pin 9 (1+) which is the Anode of the #1 LED set, then pin 12 (1-) is the Cathode of LED #1 set, this pin is returned to circuit ground via MOSFET Q9355 and the current sensing resistor R9381.
1) No main board connected to the power supply board.
2) Are you still getting the same Voltage on the power supply connector that goes to the main board as reported in post #3?
3) TV not plugged into the AC outlet, LED connector in place, SET dc meter to be able to read 400 VDC then put DC meter black lead on the negative leg of C9071, put red probe on the CH1 test point (the leg of the resistor R9030.
4) Keep an eye on the meter while plugging the TV into the AC outlet and see how high the Voltage jumps up to and wait 10 seconds to see how low it goes down to.
5) Report the result.
Power supply/LED driver board P/N BN44-00807A.
https://www.shopjimmy.com/samsung-bn...led-board.htm#

5) I got about 98 v high and 88 v low over the 10 seconds plus with the LEDs connected , but Main board not connected with the Lead on negative of C9071 and CH1 test point.

[lfhlaw]

Re: Samsung UHD UN50JU6500

What did you use for meter ground? If now you do not even have 8V standby Voltage then some thing must have got worst since you did have 13V when all the boards are connected, it is measurement error.
Meter is set correctly?

I had the Red lead on the A13V and the black lead on the TV metal chassis. Meter was set to 20V DC as was looking for low voltage of 8 and 13 v.

[budm]

Re: Samsung UHD UN50JU6500

Since the board is no longer mounted to the metal chassis you cannot use the chassis as the ground for the meter, you have to use the ground pin on the connector that goes to the main board instead.
You should also use bigger insulation sheet so you do not accidentally short out the live circuit to the chassis, I.E. the heatsinks. Also do not touch any thing in the hot deadly side of the circuit, you should at least plug the TV into the GFCI outlet.
BTW, you do have tools to do surface mounted component repair, correct?

[lfhlaw]

Re: Samsung UHD UN50JU6500

Since the board is no longer mounted to the metal chassis you cannot use the chassis as the ground for the meter, you have to use the ground pin on the connector that goes to the main board instead.
You should also use bigger insulation sheet so you do not accidentally short out the live circuit to the chassis, I.E. the heatsinks. Also do not touch any thing in the hot deadly side of the circuit, you should at least plug the TV into the GFCI outlet.
BTW, you do have tools to do surface mounted component repair, correct?

ok understood.

I Do not have tools to do surface mounted component repair. I was assuming we were testing to see if the board was bad or not. I can do simple repairs like capacitors, and maybe the resistors but smaller stuff or chips I cannot.

[Diah]

Re: Samsung UHD UN50JU6500

ok Diah wanted some additional pictures. Including complete set up.

from yours first POST you have all voltage correct A13 13V. ps on ok. only you have LED indicator blinking as there fault at LED BL and you found 5 bad LED.

my question to you.. you replaced whole strips or just only one which had the 5 bad LED. could you show me the strips you changed the label of it and the OLD Original one..?

thought the problem you have now just happened direct after replacing LED.. need to go back to this point to check this replacement. to avoid more damage

[lfhlaw]

Re: Samsung UHD UN50JU6500

from yours first POST you have all voltage correct A13 13V. ps on ok. only you have LED indicator blinking as there fault at LED BL and you found 5 bad LED.

my question to you.. you replaced whole strips or just only one which had the 5 bad LED. could you show me the strips you changed the label of it and the OLD Original one..?

thought the problem you have now just happened direct after replacing LED.. need to go back to this point to check this replacement. to avoid more damage

No the originally what I did was replace just the bad one FIRST and noticed the very dim blinking lights. Then I proceeded to replace them all to see if it made a difference.

I replaced all the LED strips..not the individual LEDs. I got the strips from ShopJimmy. I tested them with the LED tester and they all work.

Unless it is a bad batch of LEDs strips from Shopjimmy.

[budm]

Re: Samsung UHD UN50JU6500

5) I got about 98 v high and 88 v low over the 10 seconds plus with the LEDs connected , but Main board not connected with the Lead on negative of C9071 and CH1 test point.

But where are the results for #2 when #1 is performed? #2 is important data.

[lfhlaw]

Re: Samsung UHD UN50JU6500

But where are the results for #2 when #1 is performed? #2 is important data.

Just Checking before I test again so i understand. You want me to re-check the Pin 8 - power on voltage correct to the main board with LED plugged in and AC power.

or something different?

[budm]

Re: Samsung UHD UN50JU6500

Just Checking before I test again so i understand. You want me to re-check the Pin 8 - power on voltage correct to the main board with LED plugged in and AC power.

or something different?

Nope.
"2) Are you still getting the same Voltage on the power supply connector that goes to the main board as reported in post #3?"
See the Voltages you reported in your post #3, so without the cable between main board and the power supply board connected, what Voltages are you getting on all those pins of the power supply connector?

[lfhlaw]

Re: Samsung UHD UN50JU6500

Nope.
"2) Are you still getting the same Voltage on the power supply connector that goes to the main board as reported in post #3?"
See the Voltages you reported in your post #3, so without the cable between main board and the power supply board connected, what Voltages are you getting on all those pins of the power supply connector?

Yes I'm still getting the same voltages as post#3.

[lfhlaw]

Re: Samsung UHD UN50JU6500

OP: Did you test as suggested in my post #14?
Connector CNM803 pin 8 (PWR-ON/PS-ON) has pull-up resistor for self-test function. If the PS-ON is not present, the A13V will be about 8V, when the Main board board is disconnected (PS-ON pin on the main board side has open Collector circuit) from the Main board, the PS-ON will be pull up high which will cause the Voltage at A13V pins to go from 8V to 13V, at the same time the PFC boosted Voltage on the main cap will jump up from 160VDC to about 380 ~ 400VDC.
So What are the Voltages at the CNM803 when main board is NOT connected? The result will tell us which control pins have pull-up resistors or not.

Ok I did the A13V which fluctuated from 4v to 8V. the 8V standby side had 0 Volts.

The Power-on with ground read little either 0.7 or 0 Volts.

[budm]

Re: Samsung UHD UN50JU6500

1) Your post #34 (Yes I'm still getting the same voltages as post#3.) you indicated that you get the same reading as in post #3 without having the main board connected as instructed in my step #1 (Disconnect power supply board from main board), step #2 take the reading of all the pin of the power supply connector that goes to the main board.
Your Post #3 readings:
Pin Label Voltage
pin 1 Fail Count 0 V
pin 2 ANA Dim 3 V
pin 3 A13v 13 V
pin 4 OD On/OFF 3 V
Pin 5 A13v 13 V
pin 6 PWN Blu 3 V
pin 7 A13v 13 V
pin 8 Power On 3 V
pin 9 A13 v 13V
Pin 10 Ground
pin 11 Ground
pin 12 Ground


2) Now your post #35 now you indicated:
"Ok I did the A13V which fluctuated from 4v to 8V. the 8V standby side had 0 Volts.
The Power-on with ground read little either 0.7 or 0 Volts."
Your data does not make any sense to me. Post #34 you get steady Voltages, now post #35 you do not. Hard to help with bad data. The thread is now at #36.
May be it is time to buy LED tester and the working power supply board to try.

[lfhlaw]

Re: Samsung UHD UN50JU6500

1) Your post #34 (Yes I'm still getting the same voltages as post#3.) you indicated that you get the same reading as in post #3 without having the main board connected as instructed in my step #1 (Disconnect power supply board from main board), step #2 take the reading of all the pin of the power supply connector that goes to the main board.
Your Post #3 readings:
Pin Label Voltage
pin 1 Fail Count 0 V
pin 2 ANA Dim 3 V
pin 3 A13v 13 V
pin 4 OD On/OFF 3 V
Pin 5 A13v 13 V
pin 6 PWN Blu 3 V
pin 7 A13v 13 V
pin 8 Power On 3 V
pin 9 A13 v 13V
Pin 10 Ground
pin 11 Ground
pin 12 Ground

The PSU Board was attached to TV in post#3 and the voltages were with the main board not connected to the PSU but LEDs Connected. I was testing the pins on the PSU(3rd Pic). The Voltages in Post 3 did fluctuate for the A13V but I assumed that was normal. The PS-ON did a little bit but stayed mostly at 3-4 V.


2) Now your post #35 now you indicated:
"Ok I did the A13V which fluctuated from 4v to 8V. the 8V standby side had 0 Volts.
The Power-on with ground read little either 0.7 or 0 Volts."
Your data does not make any sense to me. Post #34 you get steady Voltages, now post #35 you do not. Hard to help with bad data. The thread is now at #36.
May be it is time to buy LED tester and the working power supply board to try.

This was with the PSU Separated from the LED and Main and just plugged into AC and PSU Flipped over. I was testing based on your picture you posted and that's what I got.

so the one pic. Was ground to A13V which was fluctuating form 4-8 Volts.
The 2nd pic was ground to the PS-ON which was reading pretty much 0 V. Maybe bad placement or not grounded correctly there.

I've included a couple of youtube videos of the fluctuation at the T-con fuse(I know I know) disconnected, but it's what I've saying about the power fluctuating.

T-con blue light blinking and fuse power fluctuating.
https://youtu.be/G2VdnkdMrPA

Main board blinking red at optical port and Blue lights at T-con. (synced together)
https://youtu.be/v9Fdz4_-RI4

[budm]

Re: Samsung UHD UN50JU6500

Your Post #3 readings:
Pin Label Voltage
pin 1 Fail Count 0 V
pin 2 ANA Dim 3 V
pin 3 A13v 13 V
pin 4 OD On/OFF 3 V
Pin 5 A13v 13 V
pin 6 PWN Blu 3 V
pin 7 A13v 13 V
pin 8 Power On 3 V
pin 9 A13 v 13V
Pin 10 Ground
pin 11 Ground
pin 12 Ground
So you are getting all the above Voltages when the main board and the main board not connected, correct? What did you use for Ground, PIN 2 like you show in your last two pictures?
Based on your last two pictures (https://www.badcaps.net/forum/attach...5&d=1554867815, https://www.badcaps.net/forum/attach...4&d=1554867815) I have no idea why you have Black probe of the meter on pin 2 which ANA-DIM, it is not Ground pin.
I think you should start it over since you are using pin 2 for the ground point for your meter based on your pictures.
Pictures provided by shopjimmy.

[Diah]

Re: Samsung UHD UN50JU6500

ok. now i understand what are you talking on. also after you replace the BL strips,MB unplugged BL LEDs Flashing dim as you have now at T-CON or Optical indicator on MB..

1- check if yours replacement Strips had same LEDs amount in Total as yours Old one. and test them again as you wrote before they some how flashed once bright.

2- replace your PSU, you have surface mounted component Open / Fault. not easy to you handle them.

3- keep in mind if MB unplugged you should have bright stable LED BL

[lfhlaw]

Re: Samsung UHD UN50JU6500

Your Post #3 readings:
Pin Label Voltage
pin 1 Fail Count 0 V
pin 2 ANA Dim 3 V
pin 3 A13v 13 V
pin 4 OD On/OFF 3 V
Pin 5 A13v 13 V
pin 6 PWN Blu 3 V
pin 7 A13v 13 V
pin 8 Power On 3 V
pin 9 A13 v 13V
Pin 10 Ground
pin 11 Ground
pin 12 Ground
So you are getting all the above Voltages when the main board and the main board not connected, correct? What did you use for Ground, PIN 2 like you show in your last two pictures?
Based on your last two pictures (https://www.badcaps.net/forum/attach...5&d=1554867815, https://www.badcaps.net/forum/attach...4&d=1554867815) I have no idea why you have Black probe of the meter on pin 2 which ANA-DIM, it is not Ground pin.
I think you should start it over since you are using pin 2 for the ground point for your meter based on your pictures.
Pictures provided by shopjimmy.

Ok I didn't realize I had the black lead on pin 2 (which I thought was pin 1). I tested it briefly this morning and got much better numbers similar to post#3. I will post the voltages and variance when I get back from work and if not too tired lol.