Re: LB5550 Backlight blinks
looks like BLU202B
looks like BLU202B
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Re: LB5550 Backlight blinks
BL0202B (BL0200 series)
https://cdn.badcaps-static.com/pdfs/...bf5e314100.pdfNever stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
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Re: LB5550 Backlight blinks
ok so i checked all the pins in reference to ground and there are no shorts on this IC. what should i be looking for next?Attached FilesComment
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Re: LB5550 Backlight blinks
There is problem with the LED string that is connected to pin 3 and pin 4 of the LED connector, that Voltage reading on pin 3 Cathode return is way too high. You need to verify the Voltage reading again on pin 3 of the LED connector.
The IC Voltage boosters are working otherwise you will not have those High Voltage on the LED + pins.Last edited by budm; 06-12-2018, 12:45 PM.Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
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Re: LB5550 Backlight blinks
ok i'll double check my readings again. i see the output voltages for LOW and HIGH labeled on my PSU at 145V and 218V. How can i tell what the cathode return is supposed to be?Comment
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Re: LB5550 Backlight blinks
It should be around 20 ~30V rangeNever stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
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Re: LB5550 Backlight blinks
i double checked the readings at the LED pins and they are as i posted beforeComment
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Re: LB5550 Backlight blinks
1) TV OFF.
2) Remove the LED connector.
3) Set meter to over 200V scale
4) Keep black meter probe on chassis.
5) Put red meter probe on pin 4 of the LED connector on the power supply board.
6) Turn on the TV and see how high the Voltage jumps up too and wait 10 seconds to see how low it goes down too.
7) Repeat step 5 ~ 6 but move the probe to pin 3. Do the same again on pin 2, pin 1.Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
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Re: LB5550 Backlight blinks
with the LED connector unplugged, pin 1 and 3 are 0V pin 2 fluctuates between 160 and 170 pin 4 fluctuates between 205 and 215Comment
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Re: LB5550 Backlight blinks
finally got a chance to open the TV all the way to see the LED strips and found many LEDs burnt out. Changing them out now.Comment
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Re: LB5550 Backlight blinks
Another fail LED problem, so typical and sad.Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
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Re: LB5550 Backlight blinks
yup, thanks for all the input though. learned a lot here.Comment
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Re: LB5550 Backlight blinks
All these posts where obviously some LEDs are faulty. You should have stripped out the screen and powered the set up on its back where you would have seen faulty non lighting LEDs.Comment
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Re: LB5550 Backlight blinks
Taking apart the LCD panel is the last thing you will want to do only after other tests have been done first.Last edited by budm; 06-18-2018, 03:53 PM.Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
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Vizio e601i-A3 - Has Sound and Display, But No Backlight - Bad Power Supply Board or Bad LED Bulbs ?I was given this TV from my great uncle. He said it just wouldn't turn on one day out of nowhere, replaced the TV, and gave it to me to possibly fix and use for myself.
Upon bringing it home and plugging it up, it showed a standby light.
I powered it on and without a flashlight, the display showed the "V" but the lighting is very dim, but visible.
The screen seems to blackout and stay black, but with a flashlight I can see the display.
With my Playstation 4 connected via HDMI, and running a game I can hear sound.
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Hello,
I am currently troubleshooting an LG 60UH8500 TV (2016 TV). Any help or suggestions would be appreciated.
Overall Issue: When TV is turned on, backlights all come on for about 10 seconds, then all go out. There is sound and there is a picture on the display (obviously hard to see without backlights, but it is there).
What I Have Done So Far: 1) Removed the back TV cover to expose the boards (Power Supply, Tcon, and Main), 2) blew out any dust and cleaned all connections, 3) Noticed that the LED backlights are fed from two separate connectors... -
This set has the known reputation of failed led backlights. The set does not turn on, but when plugged in, the power led stays lit for about 5 seconds followed by two short blinks and then it repeats itself. While shinning a flashlight on the screen, you can make out the Sharp logo, then it goes out and repeats the cycle. I measured some voltages across the led backlight connector. What has me puzzled is that when I place the negative lead of my vom on the led backlight pin connector (in which the black wire going to the leds was), I measure as high as -228volts, and then it falls to -95 volts... -
Hi. Recently serviced a damaged A1466 Macbook Air. Thought to post the issues and resolution for each.
Macbook AIR Model A1466 Diagnostic 09-01-2021
Issue: Liquid damaged (beer spill) Macbook AIR will not power up.
Problems & Resolutions
1) Attached Apple magsafe power adapter. No green / no orange light. This confirms the absence of the PP3V42_G3H voltage rail. The PP3V42_G3H rail is the primary voltage rail necessary to communicate with the magsafe power adapter to report the green or orange light status to the end user....09-01-2021, 09:31 AM -
Problem
This is an LG edge LED lit LCD Display. The LEDs are on the bottom edge of the display. There are 2 bars (left and right) Each bar has many LEDs and a 6 pin connector. Each pin drive several LEDs thus is the highest current flow / heat junction. The weak lead free solder gradually fails with thermal expansion/contraction cycling and increases resistance. PSU will compensate up to a point, then when the current is too high, PSU just shut down the backlight causing a dark display. I have even seen one which the connector just fell off as solder points became completely detached....
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