Re: RCA RLED4778A No Backlight no Pic No Response
Same tv, same symptoms. 400deg for 10 mins in the oven for the main board and it works again
Mayn
Senior Member
Last Activity: 12-29-2022, 09:30 PM
Joined: 11-12-2016
Location: halifax, Nova Scotia
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Re: Toshiba 58L4300UC Dim picture
So I had an idea last night.
I figured that if the power supply should be putting out 137V to the backlights but it's only putting out 115V, that if I did a bit of soldering and jumpered 4 led's per string that it should work out about right.
So I did it. Did it in a kind of random pattern so as to not end up with a dark spot on the screen. I have to say, it works great now. Brightness is where it should be. I can even dim the backlights lolLeave a comment:
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Re: Toshiba 58L4300UC Dim picture
There is an auto dimming feature, but I have it turned off. Worth a shot thoughLeave a comment:
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Re: Toshiba 58L4300UC Dim picture
Or any ideas on how to boost the voltage going to the LEDs? I can't just give up on this tv. The image is perfect, just can't make it brighter.Leave a comment:
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Re: Toshiba 58L4300UC Dim picture
Anyone have either power supplies lying around collecting dust they want to get rid of cheap? LolLeave a comment:
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Re: Toshiba 58L4300UC Dim picture
Yes, the image was dim before I repaired the strip.
Hmmm, very interesting about the power supply board. the person I got it from said the main board had been changed, but could easily have been mistaken as they had someone do it for them. gonna have to do some more digging on that one.
Wonder what the difference is. Can't be much.Last edited by Mayn; 04-14-2017, 06:17 PM.Leave a comment:
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Re: Toshiba 58L4300UC Dim picture
I keep coming back to this tv. Only power supply I can find is on Ebay and it's quite pricey. If I knew 100% this was the problem I'd get it, but if it's just an ic i'll change that first and try it. Anyone got a schematic for the power supply PK101W0220I ?Leave a comment:
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Re: Toshiba 58L4300UC Dim picture
any idea what voltages I should be seeing from O9908B? Or where else should I be looking?
Also, I almost looks like this ic got hot. Looking at the solder points on it, it just doesn't look as slick and clean as the other chips soldered to this board.
Think I could just replace it and hope for the best?Last edited by Mayn; 03-22-2017, 05:50 AM.Leave a comment:
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Re: Toshiba 58L4300UC Dim picture
That's probably the issue. The trick is, what's causing it lolLeave a comment:
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Re: Toshiba 58L4300UC Dim picture
Could a bad t-con board cause a dim picture? Almost worth the risk lolLeave a comment:
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Re: Samsung LN55C610N1FXZC no image screen flashes
So I got a replacement t-con board. Installed it and powered up.
Got image, but it does seem like a couple bad tab bonds cause of vertical bands in a couple spots. So I left it on for a bit to see what happens.
Now I don't get any image at all. Think the bad tab bonds is taking out the t-con?Leave a comment:
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Re: Toshiba 58L4300UC Dim picture
Backlights all just kind of glow, not nearly as bright as they should be. Even with the resistor between PWM and 5v there is no change.Leave a comment:
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Re: Samsung UN40C5000 no picture or backlights
Finally had a chance to get the voltage readings.
Power supply to main board 18 pin connector
1. D12V -12.8
2. DET -3.6
3.D12V 12.8
4.BL -4.9
5. D12V -12.8
6. PWM -0.5
7. GND - 0
8. H-sy -2.2
9. GND -0
10. GND-0
11.D5.3- 5.3
12. GND -0
13. D5.3 -5.3
14. D5.3-5.3
15. VAMP-12.8
16. SB -5.3
17. VAMP-12.8
18. PS -0.8
I also measured what I believe to be the wires going to the backlights at the top of...Leave a comment:
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Re: Toshiba 58L4300UC Dim picture
So, finally got a chance to get back to this tv.
Backlights all have 115V across them, but still have no ability to adjust the brightness of the image, it just stays dim.
If I go into the menu and adjust the mode from standard to movie etc... when I make a selection the brightness does jump up for a split second before settling back to being dim.
Any ideas?Leave a comment:
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Re: Rca rlded5078a-d no backlight
I just fixed the same tv with the same symptoms. Was a bad led. luckily I had spares.Leave a comment:
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Re: Samsung UN40C5000 no picture or backlights
Good eye. I didn't notice it, but yeah, something has obviously gotten inside the tv.
I'll get the readings in a bit, but it's going to be hard because the connector has 2 sets of pins in it. I'll figure something out.Leave a comment:
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Samsung UN40C5000 no picture or backlights
Picked up a Samsung UN40C5000.
Turns on, sound works, but no picture or backlights.
Don't see any image doing the "flashlight test" either.
Any ideas?... -
Re: Samsung LN55C610N1FXZC no image screen flashes
That's what I'm thinking. Might be worth it.Leave a comment:
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Re: Samsung LN55C610N1FXZC no image screen flashes
I took it apart further and looked at the tab bonds. I don't really see any sign of any liquid ever being on them. Turned it on and tapped on them with no difference.
Does this sound like maybe it's as simple as a bad t-con board?Leave a comment:
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Re: Samsung LN55C610N1FXZC no image screen flashes
Oh great lol. Any solution ?Leave a comment:
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