I checked those diodes, the transistors, and the caps on that side of the board. The diodes and transistors are okay, the caps aren't shorted, but there's no voltage to anything on the cold side. All of the caps are in the double digit mV with one being -50mV.
I ordered a board from SJ because it was super cheap. They had it listed for $7.20 and I sent an offer for $5 and they accepted it. I'm going away next Friday for 3 days so I had to pay $12 for delivery before then so it wouldn't be sitting outside all weekend. It's so cheap that it was worth it in this case lol. I love that...
x_orange90_x
Badcaps Veteran
Last Activity: Today, 04:50 AM
Joined: 05-22-2015
Location: Macomb, MI
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Correct, I did plug it in with main unhooked.. No backlight. I will need to remove a leg from each diode to check them, correct?...Leave a comment:
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Samsung UN55KU6300F no standby voltage
I have no standby indicator light and no light on the optical port. I checked the standby voltage on the two mosfets in the top left and they both read 30mV. I checked the fuse and it has continuity. I also checked the voltage on the two large 450v caps they both read 153v. All of these voltages are the same with and without the main board connected as well as with backlights connected/disconnected.
Nothing looks obvious like a burned ceramic disc cap or bulged electrolytic. No burned resistors, diodes, or anything like that.... -
Even though I don't understand how the main board could cause this type of display issue, I'm going to try disconnecting it and getting a test pattern on the tcon. Depending on the shades of colors in that pattern I may not see the band anyway 😒
It just doesn't make sense that it appears in some shades but not others, particularly in light but not in dark....Leave a comment:
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I tried. They cleaned up nicely too.. Didn't look blown, burnt, or anything like that. The band was still present tho. I checked them for ground shorts and they all tested good....Leave a comment:
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You sir led me to double check the area closely.. And I found the issue! Question is, can I replace then? Does the value matter significantly, or can I replace them with ones of similar physical size?
Edit: so I tried cleaning them with alcohol and they all cleaned up nicely. No physical damage that can be seen. I even checked for ground shorts on them and they all tested good. However, I still have the band 😔 what's really strange though is that if you look at the attached pictures, you cannot see it at all except for on the lightest shades of color. Like literally, it does not...Last edited by x_orange90_x; 04-12-2025, 09:11 PM.Leave a comment:
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Attached are the two boards, the original and the one I mentioned. It looks like it has all the same connectors except for the power button. It's from a 50S421.
I just want to see if the vertical band appears, but if the screen won't display right because of the size difference, I probably won't notice, right?
Edit: nevermind that, I see it's missing another connector for the LED inverter....Last edited by x_orange90_x; 04-11-2025, 04:48 PM.Leave a comment:
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😆 I just realized a couple nights ago when I was standing it up that it was 55", and then the Roku app said 55 and I'm like oh ya lol. Props to you for catching that...Leave a comment:
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It's just a loose board in my drawer. No idea what TV I pulled it from as it's long gone. I simply want to see if the band appears. If the screen is jumbled I guess that wouldn't really help me would it 🤔 nonetheless I'll post pictures of it shortly when I get home...Leave a comment:
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I found a board in my collection from a 4 series, 421 I believe, that has all of the same connectors except for the power button. If it hooks up right, is there a way to turn it on without the button? Is it safe to even try this board? I'll post pictures of it later....Leave a comment:
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Hmm. I don't own one of those unfortunately. Any other way to narrow it down?...Leave a comment:
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BGA connection issue?...Leave a comment:
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See attached photos of both icons.
I checked along the underside of each ribbon on both the LCD side and the scaler side. I did not find any corrosion at all. I also didn't notice any COF getting particularly hot. I will double check these things again next time I go to mess with it....Leave a comment:
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I think maybe you're misunderstanding what's happening here.
Original tcon = perfect image other than this wide translucent band
Replacement tcon = Constant flashing screen, thin black vertical line, polarized colors
I've swapped between them several times now. The results are always the same. The same symptoms always immediately begin when I put the replacement in. They always go away when I swap back to old one.
Water damage is possibly not even a factor. The guy said a dehumidifier hose running across the ceiling dripped into the tv and he...Last edited by x_orange90_x; 04-09-2025, 12:07 PM.Leave a comment:
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The single black line is only present with the replacement tcon from eBay that I have deemed defective. The below image is what I have now, and part of, the original problem....
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Being that it's a single band always in the same spot it couldn't be anything but the scaler board it the LCD ribbon connecting it, right? I verified the capacitors are not shorted, and upon visual inspection everything looks fine. I really, really expected to find corrosion down there....Leave a comment:
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I believe I mentioned that in the very first post. So far though I have not seen any indication of water ever being inside. No corrosion on any components, no splash or water stains anywhere,, nothing. I HAVE swapped out the ribbons from the tcon to panel from another tv but that made no difference. I don't believe I have a spare lvds cable but I will check later. I'm not sure where to go from here. The band is so light on most colors it's almost not noticable... But on the you can see it quite clearly. I've also noticed a faint pink "fuzz" along the top and side edges, most noticable...Leave a comment:
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Are you saying BGA is the cause of the band, or it's the cause of the lines after a few minutes? Keep in mind the guy I got this from said water dripped into it from his ceiling and after that it showed the lines. That's why I'm looking for corrosion.
I think I know why the replacement isn't working properly. None of the packaging is anti-static, and it obviously goes through X-ray machines at the post office. Perhaps it got EMF damage? It was in a black bubble envelope inside of a regular paper mailing envelope.
Edit:
I put the new tcon back in after cleaning the...Last edited by x_orange90_x; 04-08-2025, 08:13 PM.Leave a comment:
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What leads you to think it's the main board though? The original symptoms of going to black and white stripes after a few minutes? Or the vertical shadow band on the right hand side? I honestly think the band is something happening at the tab bond. Originally I thought it would go away replacing the tcon but I still could see it.
My next method of attack here is going to be to spray the contacts of the new tcon with contact cleaner and try it again. I'll also leave it on for longer and see if it goes to stripes like the original does.
50-55" are my hot sellers...Leave a comment:
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