Samsung UN48H6350AF Black Screen w/ sound

[thetonywarren]

Just got this TV, boards seem to power on, at least main board shows light on the optical audio output, the led on front of set is on and there is a blue led on the t-con board. Sound is there when I press the power button and make selections in menu, but nothing on screen, doesnt seem to have anything with flashlight test either.....Any help would be great. Thanks!

[budm]

Re: Samsung UN48H6350AF Black Screen w/ sound

No AC to TV then disconnect the cable between the power supply and the main board then apply AC to the TV, do the backlights to come on and stay on as long as the AC is present?
We also need to to get the Voltage readings (all boards connected) of all the pin of the power supply connector that goes to the main board, there are two rows of pins, the odd number pins are the exposed pins you can get to from the top side of the board, the even number pins you need to get to them via the wire entrance of the connector.
You MUST put down pin name and follow by the Voltage reading for each pin when Power switch is off and when power switch is activated.
Power supply/LED driver board is P/N BN44-00703A.

[Andrew F. Ali]

Re: Samsung UN48H6350AF Black Screen w/ sound

no ac to tv then disconnect the cable between the power supply and the main board then apply ac to the tv, do the backlights to come on and stay on as long as the ac is present?
We also need to to get the voltage readings (all boards connected) of all the pin of the power supply connector that goes to the main board, there are two rows of pins, the odd number pins are the exposed pins you can get to from the top side of the board, the even number pins you need to get to them via the wire entrance of the connector.
You must put down pin name and follow by the voltage reading for each pin when power switch is off and when power switch is activated.
Power supply/led driver board is p/n bn44-00703a.

+100

[thetonywarren]

Re: Samsung UN48H6350AF Black Screen w/ sound

No AC to TV then disconnect the cable between the power supply and the main board then apply AC to the TV, do the backlights to come on and stay on as long as the AC is present?
We also need to to get the Voltage readings (all boards connected) of all the pin of the power supply connector that goes to the main board, there are two rows of pins, the odd number pins are the exposed pins you can get to from the top side of the board, the even number pins you need to get to them via the wire entrance of the connector.
You MUST put down pin name and follow by the Voltage reading for each pin when Power switch is off and when power switch is activated.
Power supply/LED driver board is P/N BN44-00703A.

When main board disconnected, AC power applied, backlights work.

With all boards connected and TV powered both On and Off readings are the same as shown below.

Pin Readings (All VDC)
1: 12.83
3: 12.83
5: 12.83
7: 12.83
9: 0.01

2: 3.37
4: 0.09
6: 3.34
8: 0.01
10: 0.01

Thanks, I really appreciate your help!!

[budm]

Re: Samsung UN48H6350AF Black Screen w/ sound

So where are the pin names to go with each one of those readings?

[thetonywarren]

Re: Samsung UN48H6350AF Black Screen w/ sound

Ok, sorry, I thought the PIN numbers were the names. Are the actual "names" labeled on a table on the board itself?

Thanks!

[budm]

Re: Samsung UN48H6350AF Black Screen w/ sound

https://www.badcaps.net/forum/attach...5&d=1559357105
If you look at the pinout chart, you will see pin number and the name of the pin, just edit your post to add pin names.

[thetonywarren]

Re: Samsung UN48H6350AF Black Screen w/ sound

When main board disconnected, AC power applied, backlights work.

With all boards connected and TV powered both On and Off readings are the same as shown below.

Pin Readings (All VDC)
1: 12.83
3: 12.83
5: 12.83
7: 12.83
9: 0.01

2: 3.37
4: 0.09
6: 3.34
8: 0.01
10: 0.01

Thanks, I really appreciate your help!!

Pin Readings (All VDC)
1: A13V: 12.83
3: A13V: 12.83
5: A13V: 12.83
7: A13V: 12.83
9: GND: 0.01

2: OD/UD: 3.37
4: BLU ON/OFF: 0.09
6: PS ON/OFF: 3.34
8: GND: 0.01
10: GND: 0.01

[budm]

Re: Samsung UN48H6350AF Black Screen w/ sound

"4: BLU ON/OFF: 0.09" Main board is not sending the command signal to turn on the backlights circuit.

My post #2:
"No AC to TV then disconnect the cable between the power supply and the main board then apply AC to the TV, do the backlights to come on and stay on as long as the AC is present?" Did you do that test?

[nomoresonys]

Re: Samsung UN48H6350AF Black Screen w/ sound

"4: BLU ON/OFF: 0.09" Main board is not sending the command signal to turn on the backlights circuit.

My post #2:
"No AC to TV then disconnect the cable between the power supply and the main board then apply AC to the TV, do the backlights to come on and stay on as long as the AC is present?" Did you do that test?

Yes backlights on, confirmed in post #4.

[budm]

Re: Samsung UN48H6350AF Black Screen w/ sound

OK, I miss that, so main board troubleshooting next.

[nomoresonys]

Re: Samsung UN48H6350AF Black Screen w/ sound

Looks like they want about 100 dollars for the mainboard one there on ebay from shopjimmy, does have a make offer option: https://www.ebay.com/itm/Samsung-BN9...IAAOSwCA5cX79T

[thetonywarren]

Re: Samsung UN48H6350AF Black Screen w/ sound

Ok, so what can we do to troubleshoot the main board next......I'd rather try to troubleshoot repair main board first, before buying one......

[nomoresonys]

Re: Samsung UN48H6350AF Black Screen w/ sound

Could try reflowing the bga chip, trick is to heat it enough to melt the solder under the chip, overheating can kill it, usually the fix don't last too long but if it works after the reflow, you know what the problem is. Here's one example on an lg, there's probably plenty more that go into greater detail: https://www.youtube.com/watch?v=SfVnVl6Q0sk

[diif]

Re: Samsung UN48H6350AF Black Screen w/ sound

Ok, so what can we do to troubleshoot the main board next......I'd rather try to troubleshoot repair main board first, before buying one......

Here's the service manual, there are some voltages to check on the mainboard to start.

[thetonywarren]

Re: Samsung UN48H6350AF Black Screen w/ sound

Are you suggesting the pins on pages 5-7 and 5-8 of all the connections? are there specific areas of the board I should focus on and look for particular voltages? Any help is appreciated.

Thanks!

I'd rather try to troubleshoot it this way before trying to re-flow the BGA.....

[diif]

Re: Samsung UN48H6350AF Black Screen w/ sound

Are you suggesting the pins on pages 5-7 and 5-8 of all the connections? are there specific areas of the board I should focus on and look for particular voltages? Any help is appreciated.

Thanks!

I'd rather try to troubleshoot it this way before trying to re-flow the BGA.....

The voltages I was mentioning to check are on page 4-4 to 4-6.

[thetonywarren]

Re: Samsung UN48H6350AF Black Screen w/ sound

So I tried following those steps and testing/troubleshooting, but some of the steps did not make sense or I couldnt find the components that were referred to on some of the steps.....I did get some readings though....The first one looks suspect to me, but not sure what that eludes to.

L204: 1.55v
L201: 5.15v
IC202: 3.32v
L203: 3.37v
L306: 1.04v
L305: 1.16v
L2001: 5.04v

[boyebaran]

Re: Samsung UN48H6350AF Black Screen w/ sound

hi
you can try re flashing firmware.

[diif]

Re: Samsung UN48H6350AF Black Screen w/ sound

So I tried following those steps and testing/troubleshooting, but some of the steps did not make sense or I couldnt find the components that were referred to on some of the steps.....I did get some readings though....The first one looks suspect to me, but not sure what that eludes to.

L204: 1.55v
L201: 5.15v
IC202: 3.32v
L203: 3.37v
L306: 1.04v
L305: 1.16v
L2001: 5.04v

Yes, that does look suspect, it's where I would focus my attention. Can you take a photo of that area ?