Samsung UE19ES4000wxzt turns off and turns on

[Luis8]

Hi, i am not an expert with electronics so please have patience.

I got this tv from my mother in lawm, it worked just fine until yesterday when suddenly it started to shut off and on continuosly.
I measured voltages on the primary and the secondary and they all seems ok. When the TV reboots the 5V going out from PSU to the maiboard drop until the reboot is completed.
Another things that i noticed is that when the TV reboots the processor on the mainboard is a little bit hot.

Being that i have the same PSU of this thread and similar defect i resoldered all the pins listed in that image but unfortunately it did't changed the behavior.


Sometimes the TV runs correctly and remain on and stable for hours. I was able to have it running for two hours straights with no faults, then i turned it off trough the remote control and leave it for 30 minutes... When turned on it started with the bootloop again.

At this point i can't understand if the fail is in the PSU or the mainboard.

Do you have any idea?

[nomoresonys]

Re: Samsung UE19ES4000wxzt turns off and turns on

Your answer may be there in his first post of the link you give, try the eeprom reset if you didn't already, see what happens.

[Luis8]

Re: Samsung UE19ES4000wxzt turns off and turns on

You are right, tomorrow i will try the eeprom reset and update the thread with results. Thanks for the moment

[Luis8]

Re: Samsung UE19ES4000wxzt turns off and turns on

I tried the eeprom reset both connecting GND+SDA and VCC+SDA but no luck.
I was also able (one time today once the TV it's been on) to enter factory menu and performed the factory reset but the fault remain.

Can someone suggest how to proceed or what's worth to check/try?

Thanks guys!

[nomoresonys]

Re: Samsung UE19ES4000wxzt turns off and turns on

Try unplug tv from power, unhook cable from powerboard to mainboard, leave unhooked, plug power cord back into powerboard, what is the result? does the backlight come on? recheck those voltages, is the standby voltage steady now? what voltage do you get on the rest of the pins?

[Diah]

Re: Samsung UE19ES4000wxzt turns off and turns on

Yours Mother in law love you so much.... do Resoldering all joints on power boards if it fix then good, if not take it back to in law and install it at her kitchen to keep the set always warm. :-)

[Luis8]

Re: Samsung UE19ES4000wxzt turns off and turns on

Try unplug tv from power, unhook cable from powerboard to mainboard, leave unhooked, plug power cord back into powerboard, what is the result? does the backlight come on? recheck those voltages, is the standby voltage steady now? what voltage do you get on the rest of the pins?

You are right, i forgot to mention that in the first post. Yes if i disconnect the mainboard from the PSU the backlight turn on without issues.
These are the voltages that i measured without the mainboard connected:

pin 1 B13v 12.79v
pin 2 EPWM 3.31v
pin 3 B13v 12.79v
pin 4 N.C. /
pin 5 Vamp 12.79v
pin 6 B_ON 4.66v
pin 7 Vamp 12.79v
pin 8 GND
pin 9 GND
pin 10 GND
pin 11 B5V 5.25v
pin 12 A5V 5.25v
pin 13 B5V 5.25v
pin 14 P_ON 3.10v

I was able to have it on after a while today (after a thousand of prays ) and i measured the voltages while the TV was on, they are the following:

pin 1 B13v 13.20v
pin 2 EPWM 0.63v
pin 3 B13v 13.20v
pin 4 N.C. /
pin 5 Vamp 13.20v
pin 6 B_ON 5.14v
pin 7 Vamp 13.20v
pin 8 GND
pin 9 GND
pin 10 GND
pin 11 B5V 5.21v
pin 12 A5V 5.24v
pin 13 B5V 5.21v
pin 14 P_ON 3.33v

I also desoldered two capacitors used to stabilize the 5V (10v 1000uF) and measured with an ESR meter:

1. 1 - Capacity: 1024 uF (ESR 0,19)
2. 2 - Capacity: 984 uF (ESR 0,23)

They seems OK to me.

What do you think about it? Any other idea?

Yours Mother in law love you so much.... do Resoldering all joints on power boards if it fix then good, if not take it back to in law and install it at her kitchen to keep the set always warm. :-)

LOL this was funny Sincerely i want to try my best to repair it.
I will check again the joints and perform a full resoldering if no other ideas come here

Thanks a lot for your help and time guys!

[nomoresonys]

Re: Samsung UE19ES4000wxzt turns off and turns on

Seems like the issue is with the mainboard, maybe one of the voltage regulators? Suppose it could be a bad solder as mentioned or maybe a weak capacitor.

[Luis8]

Re: Samsung UE19ES4000wxzt turns off and turns on

Seems like the issue is with the mainboard, maybe one of the voltage regulators? Suppose it could be a bad solder as mentioned or maybe a weak capacitor.

I will check capacitors and voltage regulators of the main. At this point i will also perform resoldering of all the joints in the power supply board.

Just to know, in case of a faulty voltage regulator it is possibile a behavior like that that sometimes works for hours? From what i know voltage regulator functions shouldn't be affected by temperature variation...

Thanks, i will try these paths and let you know!

[nomoresonys]

Re: Samsung UE19ES4000wxzt turns off and turns on

They can get faulty and be intermittent, easy enough to test for proper voltage tho.