Re: Samsung UE40F6400AY relay sound and reboots continuosly
Yes with just the power supply on the bench the relay still clicking. As you told if i short PS_ON to ground the relay stops to click but as soon as release the short it start to click again.
I start to suppose that protection enable signal is my case but i see that is managed by QQ853 and so on... What approach can i apply to be more faster and to don't check component by component?
Do you have any suggestion on how i can check before the led driver IC's if i have a broken...
Luis8
Member
Last Activity: 01-31-2022, 11:12 AM
Joined: 10-09-2020
Location: World
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Re: Samsung UE40F6400AY relay sound and reboots continuosly
You are right, i am learning along the process
As you previously said QS861 is turned on and off by PCS802S photocoupler and this is managed by the high voltage section. Now i understand why you said me to replace CS804 earlier...
I tested the double diode DS811 and it is ok, i tested the zener ZDS802 too and it works fine.
On CS804 i have 22.8v when the PSU starts, when the relay is turned off it drops to 18-19v, i have the same voltage on the collector of QS801.
On emitter...Leave a comment:
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Re: Samsung UE40F6400AY relay sound and reboots continuosly
I am sorry i wasn't precise, i meant A5V voltage
I made other measurements today and i have stable voltage across DS858C and CS851 but i have 0 volts across CS854.
The only accused can be QS851, it doesn't have drain and source short-circuited and i am not sure on how to effectively test it with the multimeter but i think it is the culprit. Do you agree with me?
It never happened anymore that the PSU was able to start correctly but can a mosfet be affected by thermal malfunction?...Leave a comment:
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Re: Samsung UE40F6400AY relay sound and reboots continuosly
I corrected this statement with the following in a later post, unfortunately when i wrote that the PSU worked and made me to make fake assumptions.
In fact if you see the youtube video that i uploaded i have on the bench just the PSU and you will hear the relay turn on and off.
I measured the pins 3 and 4 of the relay:
- A5V signal drops when the relay turn on and off.
- RELAY_ON seems to be 5v
I saw QS861 that you are mentioning and it is...Leave a comment:
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Re: Samsung UE40F6400AY relay sound and reboots continuosly
I checked CS804 and CS806 with the ESR meter and they are ok but to be sure i tried to replace them. No luck unfortunately, i have the same behavior. Do you have any other suggestion?
If you can view my video: [url]https://youtu.be/-IDE-OUGtZA[/url] here just the PSU alone is connected to the power supply and i have the relay clicking issue anyway. If i try with the main board disconnected but backlight connected i have the LED that turn on and off following the supply voltage.
Sometimes...Last edited by Luis8; 02-24-2021, 02:31 PM.Leave a comment:
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Re: Samsung UE40F6400AY relay sound and reboots continuosly
Made it public, please check it.
I am not sure that the problem is the IC. But i have the relay clicking also with mainboard and led disconnected so i think that the problem is in the PSU.
Curious to know, how do you eliminated the signal of output protection? By destroying the track on the pcb?
I attached the schematic of the PSU.
Just checked the voltage on CS851 i have 5.3v and they are stable also when the relay clicks (measured with an analogic multimeter)....Leave a comment:
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Re: Samsung UE40F6400AY relay sound and reboots continuosly
Yes i checked the joints and re-do a lot of them to be sure.
I made some other measurement and testing and i was wrong, with the mainboard disconnected from the PSU the led lights are blinking because of the relay shutting of the power. When i am lucky and the TV starts correctly it seems that the backlight strips are all good.
Here i attached a picture of the front and back of the PSU, i recorded also a video to show the clicking issue:
[url]https://youtu.be/-IDE-OUGtZA[/url]...Leave a comment:
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Re: Samsung UE40F6400AY relay sound and reboots continuosly
I did it but no luck, it seems that most of the time that i am able to turn it on is when it is cold i don't know if it makes sense.
I would like to know the approach that you guys would use in this scenario where giving the power supply intermittent it's impossible to make any valuable measurement...
Anything else that i can try/check?Leave a comment:
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Re: Samsung UE40F6400AY relay sound and reboots continuosly
I already did that but no luck unfortunately... Can I make some measurement or photo to help the analysis? I don't have so much ideas on how to proceed further. Any help will be really appreciated
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Re: Samsung UE40F6400AY relay sound and reboots continuosly
Can you give more details on that please?
As I wrote if I have just the PSU alone connected the led back-light stays on but the PSU have the same behavior (relay clicking each 2 seconds and voltages drop down).
With this behavior I think that i should consider just the PSU... Can you suggest something to check?
Thank you so much!
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Samsung UE40F6400AY relay sound and reboots continuosly
Hi guys,
I friend of mine bring to me this TV because it started to reboot continuosly.
Sometime when the TV is really cold it startup correctly but when we shut it down and try to turn it on again it is stucked in bootloop.
When the TV fails to start i can hear the sound of a relay triggered in the PSU.
I tried to do some measurement and voltages are present in the connector to the mainboard but being the power supply intermittent i don't know if i can trust these measurement.
By the way if i disconnect the PSU from the mainboard the... -
Re: Samsung UE19ES4000wxzt turns off and turns on
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!
...
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Re: Samsung UE19ES4000wxzt turns off and turns on
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
...Leave a comment:
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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!
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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
Last edited by Luis8; 01-30-2021, 04:04 PM.Leave a comment:
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Samsung UE19ES4000wxzt turns off and turns on
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 [URL="https://www.badcaps.net/forum/showthread.php?t=61812"]this... -
Re: New Members - please post your introductions here
Hi all,
I am new here and i hope to learn a lot of new things from you and help if i can along the way.Leave a comment:
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