Re: Samsung LN40B500P3F - I Think I Screwed Up
That's excellent, thank you! Will I be able to continue testing for the original problem before i replace the lamp, or does the lamp need to be in working order to perform any tests? thanks again!
TransAm84
Member
Last Activity: 02-06-2016, 04:30 PM
Joined: 02-19-2012
Location: Ontario, Canada
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Samsung LN40B500P3F - I Think I Screwed Up
Hello All! I recently aquired this tv because it had an issue with the picture coming on for a split second then going dark again. I pulled the back cover to poke around a little and have done some damage in the process. I removed the PS/Invertor board to have a look at the back side, but in the process broke the end off the very top lamp. Are these lamps/bulbs replaceable? A quick google search came back with nothing. Will the picture still work with one dead lamp (assuming i fix the original problem)? Thanks in advance for the advice! -
Re: Panasonic TH-42PX75U - Can See Menus But No Picture
Assuming its a faulty A board, is there a way to repair it? Finding one online is proving to be difficult. Also, I am unsure of the function of the A Board and the D Board, can anyone explain them to me in layman terms? Thanks againLeave a comment:
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Re: Panasonic TH-42PX75U - Can See Menus But No Picture
Also there is no sound. Occasionally when cycling through the inputs I will see this green or white horizontal or vertical lines. Also, at one point, with a DVD player plugged in, I got this big white block with a thin green line above it (As seen in the pic). Thanks again...Last edited by TransAm84; 07-27-2013, 10:00 AM.Leave a comment:
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Panasonic TH-42PX75U - Can See Menus But No Picture
Hi everyone, I am fairly new to this hobby but thanks to this forum i was able to repair my computer monitor!
I picked up a 2007 Panasonic TH-42PX75U for next to nothing, knowing it had an issue. The TV turns on ok with the remote and button on tv. All menus seem to work as well as volume & channel/input display. There is no picture or sound from any input. I have checked and re-seated all cables. Can i assume the A board is faulty?
Any help is greatly appreciated. -
Re: LG L1710S 2 seconds to black? (pics)
*UPDATE* I went ahead and replaced some of the caps. I did not replace the big main cap or the 2 smallest ones. I replace C3(470uf 25v) and 3 of the 4 mid sized caps that are grouped together at the corner of the board. I did not replace the biggest one of that group (1000uf 25v) because i did not have one here. Anyways, that did not fix the problem. Still getting about a .5 second flash of picture then the screen goes dark. Thanks again for all the help so far.Leave a comment:
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Re: LG L1710S 2 seconds to black? (pics)
Using the proper method, here are my readings
U2
1 and 8 = open
2 and 8 = open
1 and 2 = 1.910
3 and 8 = open
4 and 8 = open
3 and 4 = open
U3
1 and 8 = open
2 and 8 = open
1 and 2 = .485
3 and 8 = open
4 and 8 = open
3 and 4 = .713
That bulge was some type of clear 'glue'. I have since cleaned it off so i could rear the part number....Leave a comment:
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Re: LG L1710S 2 seconds to black? (pics)
I have tested Q7 and here are the results:
Pin 1 - 5.04v
Pin 2 - 0.00v
Pin 3 - 4.96v
The part numbers on Q7 are: S, 7142, Y2
Here are the resistance readings on U2 & U3:
*I could not see any pin numbers on U2 & U3 so please see picture for pin numbering* [COLOR="Lime"]*Also U3 is mounted upside down compared to U2 and that is why the pin numbers are reversed*[/COLOR]
[COLOR="red"]U2[/COLOR]
1-2 = .001
1-3 = .001...Leave a comment:
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Re: LG L1710S 2 seconds to black? (pics)
I just want to thank everyone again for all the help. This is awsome! I will do the testing today on Q7, U2 & U3 and post my results. What are U2 & U3? I think I can name most of the components on this board but i dont know what those are called.
When doing this test, do i need everything hooked up & plugged in? Or can i just plug in the logic board and front power switch board and leave the screen unhooked?
Thanks again...Leave a comment:
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Re: LG L1710S 2 seconds to black? (pics)
The resistance from red to red = 834ohms
The resistance from yellow to yellow = 835ohms
I tested the diode and i got 820ohms one way and open (1.) the other way (I believe this is how a diode should operate?)
I tried a different power board from another monitor and everything worked good. Should that prove this power board is the problem? Or should I still do the logic board testing?
The other power board I used was from the same make and model but it was...Leave a comment:
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Re: LG L1710S 2 seconds to black? (pics)
I can't read any number numbers on U3 because there is some type of clear coating on it (like glue). U2 says Z317 & STC4F30 I think (very hard to read). I dont think D3 is burnt, just some varnish on there I think. I am not really sure about U3, I am not really sure what to look for. The solder and circuit board do look different from U2 (U3 solder is dull and circuit board is brownish). Thank you for the help so far....Leave a comment:
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Re: LG L1710S 2 seconds to black? (pics)
*UP DATE* I installed a known good power supply board into the monitor and everything work good. This tells me that the problem is definately in the power supply board and not the ccfls or the video board. I dont know if i am testing them correctly, but on one side of each transformer i am reading 839 ohms, and on the other side i am reading 0.9ohms. Both transformers read the same when i test them the same way. Is it possible I have bad caps even though they look fine? The last monitor i repaired had visably bulged caps. The caps on this...Leave a comment:
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Re: LG L1710S 2 seconds to black? (pics)
Here are some pics of the bottem of the board. The brown spot on the top of the board is from the small black square thing in the middle of the second pic (the one with no numbers on it). I have read the other posts on repairing this problem, however i do not yet have a total understanding of how these work. I am having trouble identifying some of the components. Are the inverter transformers the yellow squares with the PWI writing on them? After the screen shuts off, the power light remains on and i can see the picture if i hold a flashlight...Leave a comment:
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LG L1710S 2 seconds to black? (pics)
Hello everyone, this is my first post as i am new to the electronics repair hobby. I have re-capped my 24" monitor and replace the IC's in my projection TV but that is the extent of my electronics knowledge. This is a great site! I have read a lot of posts on this particular issue but I am still unsure which direction to go. I have an LG Flatron L1710S that when powered up, flashes a picture then goes black. I know it has some type of backlight issue because i can still see the picture with a flash light. All the caps look fine but i do not have a capacitence meter to test them. I have tried...Last edited by TransAm84; 02-19-2012, 10:57 AM.
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