Re: Toshiba 50L1400UC Blinking Backlight - replace LED strip?
I don't have the remote but have been told it stays on longer if the brightness is turned down.
I have stripped the TV down to the panel and now need to get the LCD off the inner layers. With computer monitors this is easy but lifting apart a 50" screen looks pretty scary. I'll take a dig through youtube videos and see if I can find a good tutorial on separating the layers without breaking the LCD itself.
Unfortunately I found no bad or suspect caps on the power board so I'm continuing the...
zero10
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Last Activity: 01-25-2017, 07:44 AM
Joined: 10-26-2011
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Toshiba 50L1400UC Blinking Backlight - replace LED strip?
I have a Toshiba 50L1400UC on my desk that is not working properly. After running for 3-5 minutes the backlight begins to blink on and off about once a second. I see a similar thread on here for a 50L3400U which I believe is quite similar internally. Many other people showed up in the thread, including at least one with a 50L1400UC with the same issue.
Each time it was suggested that the LED strip may be defective and should be replaced but nobody in that thread did so or if they did they never reported back to say whether it fixed the problem or not. [B]By chance does anybody who... -
Re: Dell 2007FPb - No power at all
Your main USB board is not working properly, you likely have one of a few problems there:
Blown fuse (there is one big fuse on it, white ceramic with gold ends labelled 3A)
Bad diodes (FD7, FD8, etc.)
Bad resistors feeding the switch mode power supply controller (probably the ones entombed in silicone near the top of the board)
This board turns 19V into 3.3/5/12V for the rest of the monitor. To have the power buttons work you need the 3.3V to be on, and for the panel to work you need the 12V supply. As far as I can...Leave a comment:
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Re: Dell 2007WFP(B) has 19V but no lower voltages
I've been able to remove enough silicone to get to the resistors however I can now no longer read the numbers on the top of them. I got frustrated with this so I just printed out some brackets to hold the DC-DC converter boards, cut down a piece of perfboard to mount a pin header on and built a small plug-in module that screws in where the original sat. Both monitors have been running for about a week without any issues using this setup.
I'm not against trying to fix these boards however I will need to find somewhere...Leave a comment:
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Re: Dell 2007WFP(B) has 19V but no lower voltages
Does the silicone sealer leave any residue? These are such small components that anything left behind would be a problem, they are right on the limit of my soldering ability so I'm being extra cautious.
These resistors are not in a high power part of the board and they have gone open or very high resistance. Interesting that the other identical setup on the board is not covered in silicone. I wonder if with such small components and the silicone insulating them thermally if they eventually overheated and failed...?...Leave a comment:
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Re: Dell 2007WFP(B) has 19V but no lower voltages
Sure. I don't have great lighting or more than a camera phone here at the office today so this isn't a troubleshooting picture, just a "here's what's wrong" picture
I have attached a picture of the failed resistors (mostly still entombed in silicone) and the monitor running with the makeshift power boards hanging out the back. I noticed that you don't actually need 5V for the monitor, only 3.3V and 12V so I reduced the board count to 2. So far they have been running 30 minutes and the heat sinks on them...Last edited by zero10; 02-28-2014, 05:32 PM.Leave a comment:
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Re: Dell 2007WFP(B) has 19V but no lower voltages
I didn't notice the 12V marking on this post:
[url]https://www.badcaps.net/forum/showpost.php?p=379944&postcount=145[/url]
Which meant at first I had backlights with no display but once I rechecked everything and found that issue I was able to confirm at at least one of the monitors is fully functional with my replacement power solution. I'll try to get some work done in fabricating an alternate mounting system for these power boards and checking that all components are sized appropriately then I can fully...Leave a comment:
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Re: Dell 2007WFP(B) has 19V but no lower voltages
Just a quick update - I have done some further testing and have what appears to be good news. After reading the other posts again I saw mention of one fellow replacing his large usb / power board with universal DC-DC converter boards I decided that it was worth a try to do the same with mine.
I am worried that in removing the silicone from the power board to replace the resistors will damage something else so I have shyed away from trying this.
I swapped in 2 cheap deal extreme DC-DC converter boards and...Leave a comment:
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Re: Dell 2007WFP(B) has 19V but no lower voltages
The main power board takes 120VAC and produces 19V, then passes that over to the large USB / other power board which regulates it down to 3V, 5V and 12V. The 12V is just for the speaker power bar port and nothing else. Some of the resistors under the silicone that are near the top of the board (for the buck converter controllers I think?) have gone open circuit or at least the value has gone up massively. The FETs and diodes all seem good (so far) and nothing on the board appears to be shorted (except the fuses of course). I was...Leave a comment:
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Dell 2007WFP(B) has 19V but no lower voltages
I am in the process of trying to repair 2 Dell 2007WFP (I can't recall if they are the B or not and don't have them in front of me right now so I can't check) monitors. I have torn them both down and I have found that they are both suffering from failed resistors on the large USB/power board (or at least that is the FIRST problem I have found). I have found a couple of other threads on here detailing problems and some solutions for these monitors and am trying to move ahead with repairing the 2 monitors I have.
[url]https://www.badcaps.net/forum/showthread.php?t=25636[/url]
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Re: Why did my motherboard catch fire? Also, what can be saved?
I think you are right on the "why now?" bit, there have been no recent changes, heck, the case hadn't been opened in 852 days, and I doubt a poor connection, everything is clean in there and those connectors fit quite well. Can I really just cut that part of the board off? The system did power off before I got there so I think something else must have gone with it, but that would make one hell of a story if it can be saved, quite the battle scar....Leave a comment:
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Re: Why did my motherboard catch fire? Also, what can be saved?
Oh dear, I just re-read the diagram you posted and I fear you might be right! Oh dear oh dear oh dear....
This just may be the dumbest mistake I have ever made with a computer. Quick, I need to get inside the internet and delete this entire thread before anybody can ever read it.
If I understand right, it is irrelevant whether anything was ever plugged into the port since the USB port would be grounded where it was attached, and that would indeed ground the +12V line on the firewire...Leave a comment:
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Re: Why did my motherboard catch fire? Also, what can be saved?
Your post had me panicked for a moment until I remembered there was nothing plugged into the front ports, not when it burned or at any time ever before, I never ever used them. The USB header doesn't connect anything to anything else unless a device is plugged in, so although I think you might be right and that cable is on the wrong header, it can't be a short caused by that. Or, in other words, I may be an idiot, but I think the failure is unrelated (I'm sure everybody says that....)
...Leave a comment:
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Re: Why did my motherboard catch fire? Also, what can be saved?
I can confirm that the USB port assembly that was plugged into that header is not shorted, however I had to cut the wires leading to it to check it, and since it is generally unused I will just leave it off the replacement board. I can find no signs of any foreign objects against the pins for the header either on the front or back of the board so I don't think that this was a short on the USB lines, plus, as mentioned above, that should be current limited... I have no idea what else could prompt such a failure though...Leave a comment:
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Why did my motherboard catch fire? Also, what can be saved?
I had a minor incident with my file/media server today. I'll begin with the specs:
Asus P5E-VM DO motherboard
Intel E6300 Core 2 duo
2x2GB G-Skill DDR2-1066 ram
4x1TB Western Digital hard drives
1x1.5TB Seagate hard drive
2x2TB Western Digital green hard drives
1x500GB IDE Seagate hard drive
3x120mm Scythe front fans
1x120mm Scythe rear fan
1x140mm Antec top fan
Corsair VX550 power supply
I had done TONS of overclocking in the past (1.86GHz-->3.2GHz), and have a monster cooler on the CPU and north bridge,... -
Re: Samsung Syncmaster 2243swx - 2 seconds to black
The new transformer showed up today and I swapped it in. After 30 minutes the monitor is still working great so I am giving it back to my boss and calling it repaired. Another one saved from the scrap heap!Leave a comment:
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Re: Samsung Syncmaster 2243swx - 2 seconds to black
It was a bit of a reach but I figured:
1) I have a spare known good transformer (I tested it in the correct monitor first)
2) I have a power board that I would otherwise have to replace in its entirety
Given those things there was just about nothing to lose by trying it. It was a bit of a pain to make up little 5mm high x 6mm wide z shaped jumper wires and solder them to the transformer, then mount the transformer at an angle and solder the wires to the board without heating them enough to melt the solder...Leave a comment:
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Re: Samsung Syncmaster 2243swx - 2 seconds to black
The new Samsung 932B transformer arrived today. I was wrong about it being physically compatible, the pins are about 5mm closer together on the 2243's transformer. I checked the low voltage side whore the monitor was trying to power up and it showed 2.4vac on my meter, and checking the Samsung 932B i had on my desk showed 2.1vac when running which i thought was close enough so i made up some small jumper wires and soldered in the new (incorrect) transformer. Much to my surprise it was able to light a full set of ccfls from a 19"...Leave a comment:
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Re: Samsung Syncmaster 2243swx - 2 seconds to black
I did some destructive testing of my burned transformer from another board (the burned version of the one I want to swap in) and those corner pins have no connection to them, they are not involved in any way with the feedback / sense circuitry.Leave a comment:
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Re: Samsung Syncmaster 2243swx - 2 seconds to black
I am sure that the transformers are mechanically the same (aside from one detail mentioned below), they have very similar primary winding resistance and slightly different secondary winding resistance (I expect this is because one board specifies 650V and the other says 700V), the biggest worry I have is the 2 pins located on the low voltage side of the transformer out on the corners. I think these pins provide the feedback for the driver board, telling it how much current is being drawn on each side? If so, I wonder if the transformer...Leave a comment:
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