Samsung UHD UN50JU6500

[lfhlaw]

Got this TV from a person. It does show some power with the LED lighting up and blinking LED indicator which continues.

There is no backlight when plugged in or attempted power on.
No image with flashlight.
Interestingly, the Main board optical port flashes, as well as the T-con(blu lights) syncing together i believe.
The Remote and power button on the TV seem to not really effect the Power, so I'm thinking the Main board.

Checking the power board pin voltages.
Pins To the main board.
Pins 3,5,7,9 all register about 13 v
Pins 2,4,6,8 register about 3 v
Pin 1,10,12,12 all show no voltage

Pins to LEDS
Pin 1 registers 100 v with the main board unplugged from power
Pin 1 registers 200 v with the main board plugged in.
All other pins show no power flowing through them.

So before I break down the TV to look at the LEDs. Was wondering if there was thoughts that maybe it was the Main board vs the Power supply.

or anything else that I should check.

[budm]

Re: Samsung UHD UN50JU6500

Since connectors on the power supply board label for each pin so how about putting down the pin name and follow by the Voltage of each pin.

[lfhlaw]

Re: Samsung UHD UN50JU6500

okay

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

[Diah]

Re: Samsung UHD UN50JU6500

you have 2 groups at BL, if you disconnected MB and turn on the set BL should be on. if they are not then take it apart to BL

[lfhlaw]

Re: Samsung UHD UN50JU6500

ok will have to do that first.

In the old LED TVs normally you'd get a dark image....with no backlights but sound. Did the 4k TVs change in the way they process logic with bad LEDs?

[lfhlaw]

Re: Samsung UHD UN50JU6500

Ok I did find a couple of bad LEDs and replaced All the Strips(From Shopjimmy). However, with the Main board unplugged, The LED lights are rhythmicly flashing although very dim.

If i plugged in Main board as well. Then I get a dim flash and then a brighter flash and then off again more rhythmic.

So Right now I'm thinking Power supply board is bad and either I can hunt for the bad component or just buy a new one.

[Diah]

Re: Samsung UHD UN50JU6500

Ok I did find a couple of bad LEDs and replaced All the Strips(From Shopjimmy). However, with the Main board unplugged, The LED lights are rhythmicly flashing although very dim.

If i plugged in Main board as well. Then I get a dim flash and then a brighter flash and then off again more rhythmic.

So Right now I'm thinking Power supply board is bad and either I can hunt for the bad component or just buy a new one.

disconnect the T-CON LVDS check urs BL

[Diah]

Re: Samsung UHD UN50JU6500

after you replaced the BL strips did you put back the panel in place then connected MB, or you was talking with out Panel ?

[lfhlaw]

Re: Samsung UHD UN50JU6500

after you replaced the BL strips did you put back the panel in place then connected MB, or you was talking with out Panel ?

No I did not install the panel back in yet.

[Diah]

Re: Samsung UHD UN50JU6500

No I did not install the panel back in yet.

this is fault when you connected MB ... put panel in place

[lfhlaw]

Re: Samsung UHD UN50JU6500

this is fault when you connected MB ... put panel in place

Is this different from the regular LED TVs? because normally in "plain" LEd Tvs without the panel, the LED strips will still light up without the Motherboard being attached or Panel.

Is it a new algorithm that 4k TVs do?

[Diah]

Re: Samsung UHD UN50JU6500

Is this different from the regular LED TVs? because normally in "plain" LEd Tvs without the panel, the LED strips will still light up without the Motherboard being attached or Panel.

Is it a new algorithm that 4k TVs do?

each brand name had different software system. also the protecting in software different too. yours now need to put back panel as its before.

[lfhlaw]

Re: Samsung UHD UN50JU6500

OK Replaced the panel and connected it up, but still no backlights on the panel showing up with or without the mother board connected.

[budm]

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#

[lfhlaw]

Re: Samsung UHD UN50JU6500

Unable to turn the TV off or on. But plugging in the Power into the AC cause the
Voltage from the C9701 and R3090 to cycle from 0 to 183 thereabouts.

I do get 3 v to the main board.
it appears the Power is cycling up and down.
The fuse on the T-con will show 3 v and then go to 0 then back up to 3 v.

[Diah]

Re: Samsung UHD UN50JU6500

Unable to turn the TV off or on. But plugging in the Power into the AC cause the
Voltage from the C9701 and R3090 to cycle from 0 to 183 thereabouts.

I do get 3 v to the main board.
it appears the Power is cycling up and down.
The fuse on the T-con will show 3 v and then go to 0 then back up to 3 v.

this statement will never happen unless you did some things wrongs with sockets. please upload photo on all boards together to see how they connected.. i guess there are wrong or missing cable.

[CapLeaker]

Re: Samsung UHD UN50JU6500

Unable to turn the TV off or on. But plugging in the Power into the AC cause the
Voltage from the C9701 and R3090 to cycle from 0 to 183 thereabouts.

I do get 3 v to the main board.
it appears the Power is cycling up and down.
The fuse on the T-con will show 3 v and then go to 0 then back up to 3 v.

listen to budm's post #14. First of all you have to fix the back light issue, before you frig around with the main board. The PSU has a pull up resistor (so it is forced on as soon as you plug it into mains circuit. Disconnect the main board. You can hook the main board back up AFTER you fixed the back light issue. Either you still have a bad led, bad connection or something. Measure the voltages on the LED strings with the leds, then again without the leds hooked up to the PSU.

[CapLeaker]

Re: Samsung UHD UN50JU6500

this is fault when you connected MB ... put panel in place

Whaat? Not on a Samsung with pull up resistor in the PSU. Would defeat it's purpose otherwise.

[Diah]

Re: Samsung UHD UN50JU6500

Whaat? Not on a Samsung with pull up resistor in the PSU. Would defeat it's purpose otherwise.

you are wrong. sorry....... Samsung UHD PSU and feeding T-CON and panel designed different from HD.

[budm]

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.