Re: Samsung un48ju6700 half screen ghosting problem
Okay, so I wasn't able to get back to this set until this evening.
I measured the voltages on the lowest tabs on the left and right sides. I was able to find 26V and -6.6V on both sides. I'm not sure what to conclude from this.
CityZen
Member
Last Activity: 01-16-2022, 04:21 PM
Joined: 05-25-2014
Location: NYC, NY
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Re: Samsung un48ju6700 half screen ghosting problem
Okay, so if I understand you correctly, you are saying that the right side of the screen is missing either the VGL or VGH drive voltage, and that it might be possible to fix that by measuring the testpoints on the side tabs to look for these voltages, find out where it is missing from (compare left and right sides), and then to find a source of the missing voltage (either on Tcon or bottom drive boards) and wire it to the lowest test point where the signal is missing from. Is that right?Leave a comment:
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Re: Samsung un48ju6700 half screen ghosting problem
Okay, took a while, but here are better T-Con pictures.
Also, I removed the bezel, and discovered there are side tabs....Leave a comment:
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Re: RCA RLED6090 backlight goes affter 10 minutes
If nothing else, you could add some diodes inline with the LED outputs. Each will drop the voltage a bit and thus dim the LEDs correspondingly.Leave a comment:
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Re: RCA RLED6090 backlight goes affter 10 minutes
LED brightness is typically adjusted by PWM (pulse width modulation).Leave a comment:
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Re: Samsung un48ju6700 half screen ghosting problem
T-Con:...Leave a comment:
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Re: Samsung un48ju6700 half screen ghosting problem
Yes, I just now understood what you meant after trying the experiment I mentioned.
If I leave the outer bottom board disconnected on the problematic side, the result was not as interesting as I hoped: the whole screen fails to show any image.
I did try various experiments masking out some of the connections, and they did make certain vertical bands of the screen display improperly.
After thinking about the way LCD screens are driven, I realized that the horizontal rows are only driven by timing...Leave a comment:
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Re: One vertical green line on my AQUOS LC-70LE740E TV
Okay, so I got back to my own TV and tried the experiment I mentioned earlier (leaving one bottom board disconnected). Unfortunately, the result was not as interesting as I hoped: the whole screen fails to show any image.
I did try various experiments masking out some of the connections, and they did make certain vertical bands of the screen display improperly.
After thinking about the way LCD screens are driven, I realized that the horizontal rows are only driven by timing signals, whereas the vertical...Leave a comment:
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Re: One vertical green line on my AQUOS LC-70LE740E TV
The question I asked is certainly relevant to me.
The relevance to the original poster is as I stated: it could affect which tab corresponds to the line in question....Leave a comment:
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Re: Vestel 17IPS71 + 17MB82S - no standby
This might be useful:
[url]https://www.manualslib.com/manual/1382410/Vestel-Mb82s.html[/url]Re: Vestel 17IPS71 + 17MB82S - no st...82s.html[/url]Leave a comment:
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Re: Vestel 17IPS71 + 17MB82S - no standby
It seems 24V is only used on the PS board to supply the LED driver.
If all voltages on PSU check out, then you should focus on the main board.
Perhaps check for 3V3_STBY, which seems critical. You can probe the right-side (emitter) pads for Q1/Q3 (not present). Probe the upper (collector) pads for 5V_STBY.
It looks like Q61 switches power through FS2. If it's on, you should see voltage on FS2.
Everything goes through the main chip, the MT5820L. By "everything", I mean...Leave a comment:
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Re: Any thoughts on this one ?
According to a "how to fix LCD problems" video I saw recently, that particular issue could involve anything from the main board to its connection to the T-con board to its connection to the panel. Data is getting lost along the signal path somewhere.
If you can bring up a service menu test image, you can rule out the T-con board and downstream of it. Either way, it's a good idea to check out all the cable connections.Leave a comment:
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Re: Vestel 17IPS71 + 17MB82S - no standby
Are you measuring socket voltages with cables attached or disconnected? The power supply might behave differently with no load.
According to
pin 1 of CN4 might be 24V (it's a bit unclear to me), while pin 3 is the signal to turn on the power supply, and pins 10,11,12 are 12V (other even pins are ground). Pins 5,7 control the backlight, and pin 9 is the 5V standby that isn't populated.Leave a comment:
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Re: One vertical green line on my AQUOS LC-70LE740E TV
I can understand that, but one thing is still needed: how does the data get to the drivers within the glass? The only connections are at the bottom of the screen....Leave a comment:
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Re: One vertical green line on my AQUOS LC-70LE740E TV
I just had a thought about an experiment that might help us both.
LCD screens have drivers for the horizontal lines (rows) and for the vertical lines (columns). Normally, the drivers for the horizontal lines are on the sides of the screen, and are attached similarly to how you see the tabs on the bottom of your screen.
However, on recent LCD screens, I've only seen tabs on the bottom. I've had a theory that the drivers for the sides are also fed through the tabs on the bottom of the screen. If this...Leave a comment:
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Re: One vertical green line on my AQUOS LC-70LE740E TV
I don't know, but I wouldn't do it myself. Just try probing with a wooden or plastic probe first to see if there's any effect.Leave a comment:
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Re: samsung LE32A558p3f bn44-00208a
They're mostly the same as far as I can tell. Some are more bare bones, some have nice cases and such. There could be variations in the firmware version they're running, but that might not matter much. I think they're quite an amazing value for what they can do....Leave a comment:
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Re: Vestel 17IPS71 + 17MB82S - no standby
Some TVs remember when they were on before being unplugged. Seems like your TV is on, which is why there's no standby LED.Leave a comment:
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Re: One vertical green line on my AQUOS LC-70LE740E TV
I'm not an experienced TV fixer, but based on my understanding of LCDs, the problem could be in a couple different places: the connection of the driver chip to the flex cable, or the connection of the flex cable to the actual LCD. If probing around the chip yields nothing, consider gentle probing where the flex meets the screen.Leave a comment:
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Re: samsung LE32A558p3f bn44-00208a
In reference to your original question, the taller cap has a temperature rating on it, whereas the others don't, implying that they have a lower rating.
You might pick up a cheap LCR-T4 component tester from Ebay and use it to test some of the caps you got and verify that they're within spec.Leave a comment:
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