huhuhu
samsung
aurelienr
Member
Last Activity: 11-19-2017, 07:16 AM
Joined: 11-06-2017
Location: Paris
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Re: EU40F6400 startup failure
huhuhu
samsung
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Re: EU40F6400 startup failure
With new Tcon problem still here...µI checked AVDD to GND resistance, it seems normal (several kOhms) on new board comparing to the short measured on my Tcon, but changing the board did not solve the issue.
I already spent too much time on this sh**, I bought a new TV and will try to sell the valid Tcon, the PSU and some other parts on ebay...Leave a comment:
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Re: EU40F6400 startup failure
No idea of what I could do to check MB functionnality ?Leave a comment:
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Re: EU40F6400 startup failure
Not 100% sure of new Tcon functionnality, was sold as functionnal but I can't be sure (only 40 euros on ebay).
The screen is really blanck since, as I said before, I cut one of the PWM line of the cable between MB and PSU, so that the internal pull up resistor on the PSU force one part of the backlight to be on (and it works, but nothing displayed).Leave a comment:
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Re: EU40F6400 startup failure
I changed the Tcon...still no change, same bug....Leave a comment:
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Re: EU40F6400 startup failure
I have unsoldered capacitor, it is not in shortcut. But on the board I measure a resistance of approx 3 ohms between AVDD and GND. Since you told me I should read about 12V on this plane, that would represent a 4 amp current, I don't think it is a normal current for this board (especially if it comes from the LVDS cable) !
I think I have found a Tcon board for repairing for 30 euros, I will try...Leave a comment:
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Re: EU40F6400 startup failure
Don't worry i'm freelance electronic engineer I've ordered the part in another scheduled order. But I have a lot of work and I forgot to unsolder the cap to test it alone, shame
Of course the measurement has been done with all cables disconnected.
When powering on, the AVDD was obviously 0 because its LED was off ( but I did not measured it).Leave a comment:
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Re: EU40F6400 startup failure
I ordered a new cap, I will test it tomorrow...if nothing change, I will try to find a replacement board...Leave a comment:
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Re: EU40F6400 startup failure
In a previous post I said that The LED3 was off and on the PCB I see that it is connected to the AVDD plane. It's likely that the cap I measured in short is connected to this plane, explaining why LED is not on. If fuse does not trigger that means there is either a current limiting device (but I did not detected any overheat on any component), or simply that the AVDD power is disabled in software for any reason (short protection for example).Leave a comment:
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Re: EU40F6400 startup failure
I check the tantalum caps (that often fails by creating a short), the black one on the top (marked NEF/EN7) is in shortcut. I could unsolder it to check if this is really the cap of another part that is in shortcut...Leave a comment:
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Re: EU40F6400 startup failure
Done...Leave a comment:
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Re: EU40F6400 startup failure
No picture, no backlight....but sound works and I ear I can scroll into the menu with the remote...Leave a comment:
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Re: EU40F6400 startup failure
Already done, no image. Then, as I said before, I cut one of the PWM wire from the mainboard to force one string to light on (through internal pullup on PSU), and still no image visible.
I read the schematics (link in first post) and there is no error/status/feedback signal, so yes the problem comes from the MB or the Tcon...PWM are generated from MB, but if there is no picture I would guess that there is a problem with Tcon only, but someone on the forum told me that if Tcon fails the backlight continues to operate. Is...Leave a comment:
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Re: EU40F6400 startup failure
Easy to say, without schematics and knowledge of software behavior
I will try to reflow BGA, then go to garbage and try to sell some spare parts...only 4 years old, what a shame !Leave a comment:
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Re: EU40F6400 startup failure
So... no idea of the problem origin ?
What should I do ?
If a buy a motherboard for repairing, should I take care of both the MB model AND the TV model to be sure to have the correct firmware inside ?
PS : for photos, my picrtures were too heavy for the forumLeave a comment:
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Re: EU40F6400 startup failure
Picture of the Tcon board. Only two LEDs on, LED1 and LED2. LED3 is off.
[url]https://we.tl/jR5XeUJN7Y[/url]Re: EU40F6400 startup failure<br /> ...5XeUJN7Y[/url]Leave a comment:
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Re: EU40F6400 startup failure
I made the measurements. When MB disconnected, the PWM signals are at 3.3V level and BLU_On/Off is also high.
I tried my idea of cutting the PWM4 wire and reconnected MB, the TV starts with the bottom backlight enabled, but nothing is displayed on the screen. However, I can go into the menus, I ear the clic sound of volume up/down, and when I select the "smart hub" function I get the other sound made when I scroll up/down in the selection.
Would it be possible that the Tcon board fails, so that the MB disables the backlight that...Leave a comment:
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Re: EU40F6400 startup failure
According to the schematic, there are pullup that should set them high, but I will check !Leave a comment:
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Re: EU40F6400 startup failure
Should I be able to see a very low image without backlight ?
I'm tempted by cutting one of the PWM signals to enable one of the backlights outputs and see what is displayed...if the problem is due to a memory problem I may be able to perform a factory reset ?Leave a comment:
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Re: EU40F6400 startup failure
Here we go...
[url]https://we.tl/PcDVyCZ1h2[/url]
FYI, the MB<>PSU cable and connectors/contacts are not damaged.Re: EU40F6400 startup failure<br /> ...e not damaged.Re: EU40F6400 startup failure
Here we go...
[url]https://we.tl/PcDVyCZ1h2[/url]
FYI, the MB<>PSU cable and connectors/contacts are not damaged.Leave a comment:
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