Re: Samsung EU40F6400 power cycling
i got inpatient and got a new PSU board.
fixed the problem for me.
i might try to find a solution for my broken one though, since i can't stand that i can't find what's wrong with it!
pvl87
Member
Last Activity: 04-12-2017, 12:20 PM
Joined: 09-15-2016
Location: the hague
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Re: Samsung EU40F6400 power cycling
ok, keep us posted!
i'm still looking for a solution. not much time at the moment though unfortunatly.Leave a comment:
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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!...Leave a comment:
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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 youLeave a comment:
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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.Leave a comment:
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Re: Samsung EU40F6400 power cycling
I have the same issue. When clicking, what are the voltages on the leds?Leave a comment:
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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.Leave a comment:
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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...Last edited by pvl87; 10-15-2016, 06:25 AM.Leave a comment:
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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 pro...Leave a comment:
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Re: Samsung EU40F6400 power cycling
thanks for the scematics Thoma!
here they are:...Last edited by pvl87; 10-07-2016, 12:18 PM.Leave a comment:
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Re: Samsung EU40F6400 power cycling
Thanks, i will!Leave a comment:
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Re: Samsung EU40F6400 power cycling
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...Leave a comment:
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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?Leave a comment:
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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!Leave a comment:
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Re: Samsung EU40F6400 power cycling
switched caps C9154 and C9254 with some weird results.
C9154 gives 80VDC on its new position (did 80VDC on its previous position)
C9254 gives 160 (!) VDC on its new position (did 40VDC on its previous position)
(did not connect the LED strips or main bord on testing runs)
i guess its that capacitor after all? how the heck did it go double in VDC though? tried to resolder the component with same results.
i'll see if i can get a new capacitor somewhere and try again!Leave a comment:
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Re: Samsung EU40F6400 power cycling
[url]http://electronics.stackexchange.com/questions/29787/whats-this-white-stuff-on-my-board[/url]
just non conductive bonding agent i think. i'll remove the caps and see if i can get a clue if that one cap went bad.Re: Samsung EU40F6400 power cycling<... cap went bad.Re: Samsung EU40F6400 power cyclingLeave a comment:
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Re: Samsung EU40F6400 power cycling
correct, C9254, 9454, and 9354 all have about 80VDC.
the board seems to be functioning now, with C9154 at 42VDC. maybe 40 or less means power cycling. not sure why it's showing this behaviour though.
i'm sure it will get below 40 sooner than later.
all other caps show reasonable voltages, the ones in pairs all have similar voltages compared to their neighbour. i don't think those are causing any problems.
anyone with input on my earlier question?
[I]i was thinking about switching the 2...Last edited by pvl87; 09-23-2016, 11:48 AM.Leave a comment:
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Re: Samsung EU40F6400 power cycling
i was thinking about switching the 2 capacitors (since they are both the same) and see what happens, but they are bonded. does that have cooling purposes? or just bonding?
i don't have that kind of stuff. the normal bonding only variant i do have.
is there a chance of succes if i switch the 2 capacitors?Leave a comment:
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Re: Samsung EU40F6400 power cycling
i found these online.
they're barely readable though. i couldn't tell if they match or not, you guys have any idea?...Leave a comment:
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Re: Samsung EU40F6400 power cycling
here is a picture of the underside.
i think the forum is compressing it though.
hope it's viewable!
there are 2 rectangular holes in the right of the picture, the mentioned caps are located there.
i'll do some more measuring this evening....Last edited by pvl87; 09-21-2016, 04:48 AM.Leave a comment:
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