Samsung EU40F6400 power cycling

[Moreno83]

Re: Samsung EU40F6400 power cycling

You could also put all original parts ( capacitors ) back into the board and heat it up. See if you get the same results.

Reconnect all cables in the tv and turn it on. It will cycle with the red led. Heat up the powersupply and i think that eventually the tv will turn on and will stay on. Will take about 1 or 2 minutes with a hairdryer.

I had the same with a 6100 serie.

[pvl87]

Re: Samsung EU40F6400 power cycling

i ordered some new capacitors as i could not get that faulty one back to 80VDC, for strange reasons. it got stuck at about 160VDC. i don't want to destroy anything else on the board, so i'll wait for the parts to come in and get soldering again!

[pvl87]

Re: Samsung EU40F6400 power cycling

No luck with the new caps unfortunatly. I also know where the 160vdc comes from... Those readings came up when i did not have any load on the board. On load it's back to 40 and 80 vdc. So i'm back to square one i'm afraid...

I'm running out of ideas now i guess. Should i focus on the 4 triac, transistor things that are on the same heatsink?

[pvl87]

Re: Samsung EU40F6400 power cycling

You could also put all original parts ( capacitors ) back into the board and heat it up. See if you get the same results.

Reconnect all cables in the tv and turn it on. It will cycle with the red led. Heat up the powersupply and i think that eventually the tv will turn on and will stay on. Will take about 1 or 2 minutes with a hairdryer.

I had the same with a 6100 serie.

tried that but voltages are not getting up unfortunatly. (with or without load)
it is at the point where it does stay on, but eventually voltages drops under about 40VDC and then the power cycling begins.
some sort of fail safe i guess.

i'm wondering what makes that 80VDC to the capacitors under load so i can do some measurements maybe. it should be do-able because (correct me if i'm wrong) i believe there is 2 'channels' of some sort that should do the same voltages.

i'll keep doing measurements, but i'm kind of flying blind, because i lack the skills to automatically check some key components that 'make' that 80VDC somehow.
if someone can push me in the right direction, it's much appreciated!

[thoma]

Re: Samsung EU40F6400 power cycling

Hallo guys!
Write me a private message with your e-mail Adress
and I post you the correct schematic BN44-00622B if you want!

it is available here http://televid-sib.ru/index.php?topic=27588.0

[pvl87]

Re: Samsung EU40F6400 power cycling

Thanks, i will!

[pvl87]

Re: Samsung EU40F6400 power cycling

Hallo guys!
Write me a private message with your e-mail Adress
and I post you the correct schematic BN44-00622B if you want!

it is available here http://televid-sib.ru/index.php?topic=27588.0

thanks for the scematics Thoma!

here they are:

[pvl87]

Re: Samsung EU40F6400 power cycling

looking at the scematics that 42 VDC over C9154 could be correct.
the other 3 'channels' (meanin C9252, C9354 and C9254) are all 80VDC but that is the way it's meant to be if my interpretation of the scematic is correct.

(see attached image)


could someone explain why that could be?

and if there is anything else i can check out for finding the bad component?

thanks for all the help so far anyway, i'm going back and forth, i know
it's a learning process...

[pvl87]

Re: Samsung EU40F6400 power cycling

i measured (when powercycling) CNL802 and CNM803 (see Excel file attached).
on CNM803 i'm missing some info. i need info on the yellow cells in the excel file. i don't know whether the values i measured are what they're supposed to be.

i also discovered something new.
when power cycling, voltage on VF4+ and VF3+ (pins 4 and 6 on CNL802) are 64VDC instead of 84VDC what it should be according to the scematics.
when i measure C9354 and C9454 (when powercycling) i get 64VDC aswell.


something that i want to mention,
the board is power cycling sometimes but not always.
i thought i would get the best measurements when the board was doing what it should, but i discovered i get other values when it's powercycling.

if i leave the board alone for some time and then plug in only the psu and leds, it won't powercycle.
if i hook up the mainboard, tcon etc. it will turn on once if i'm lucky, but then always powercycles. if i then unhook the mainbord etc. the PSU and leds will powercycle on their own again.
it might ring a bell to someone. just wanted to mention it to help explain the issue going on.

[Legionnary]

Re: Samsung EU40F6400 power cycling

Hello i have the same problem with a tv UE46F6500 if the power cord is disconnect for a long time, after i plug the power cord the tv power on, but if i disconnect it or try to pass in standby mode after that i have the samsung bootloop.

The half part of the backlight is ok but the lower part is flickering , in my case when the tv is working good, i have 98V on the 4 caps related to the backlight , i have checked theses caps all are ok.
I have checked all the blue caps too and some others cms but all seems to be ok...

Have you resolved the problem? are you sure the problem is on the psu and not the leds? For me i think its a bad connection, but where ?

[pvl87]

Re: Samsung EU40F6400 power cycling

i haven't solved it unfortunatly.

i'm hoping BudM or one of the other guru's around here can point us in the right direction.

[Legionnary]

Re: Samsung EU40F6400 power cycling

The problem is now for sure in the psu in my case, even without the cable for the led unplugged i have the tv clicking and sound of the relay

[pvl87]

Re: Samsung EU40F6400 power cycling

I have the same issue. When clicking, what are the voltages on the leds?

[Legionnary]

Re: Samsung EU40F6400 power cycling

the values are constantly changing but the 2 caps on the top are near the good voltages 98v and drop, but the two on the bottom are not correct , near 83v and drop.

In my case if i let the tv when bootloop, 1hour or 2 after , the tv stop bootloop and the voltages are stables. the tv is power on i can hear the sound but black screen
have you try this ?

[pvl87]

Re: Samsung EU40F6400 power cycling

what are your voltages on C9154, C9254, C9354 and C9454 when powercycling?
i don't know which you measured when you say 'the ones on the top'. on the PCB there's a number next to the component.

i have tried, but when it doesn't powercycle it just works fine. when i switch on and off though it goes back to powercycling.

[Legionnary]

Re: Samsung EU40F6400 power cycling

9154 & 9254 = 98v
9354 & 9454 = 83v

when the tv is ok , thoses 4 caps are 98V

[pvl87]

Re: Samsung EU40F6400 power cycling

It's also important to know what the voltages are when powercycling. There is a chance they are different. I would check that if i were you

[pvl87]

Re: Samsung EU40F6400 power cycling

Still got a problem with my own TV aswell.

can any of you guru's out here help me on this one?

attached is a list of voltages on the 2 main connectors.
these are the voltages when the board is powercycling.

not sure what else i can check or replace to get my TV working again...

thanks in advance!

[vinceroger69]

Re: Samsung EU40F6400 power cycling

sorry wrong thread.

[Legionnary]

Re: Samsung EU40F6400 power cycling

In my case i will try to replace one of the 2 SLC2013m, i wait for it and when received it, will post the result here