evanroheff21
Member
Last Activity: 12-06-2023, 11:20 PM
Joined: 08-28-2016
Location: Spanish Fork, UT
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I do have an LED tester, and the individual connectors are accessible from the back pretty easily. I'll give that a shot. I'll probably buy a new/used PSU to replace this one as I've about reached the depth of my troubleshooting skills at this point. -
Hmm,
I replaced the C614A capacitor with an equivalent capacitor (1000V, 333J marking) that I pulled off of an older Samsung (UN65NU7100F model) power supply (BN44-00932B). It looks the same aside from being blue instead of gray. After reinstalling into the TV and powering up, I'm getting the exact same symptoms (no backlight, short initial flash when very first connected/powered. Is it possible that my replacement capacitor is also failed in the same way? Forgive my ignorance, I'm testing these with a digital multimeter set to the ohms/resistance setting. This new (blue) one from off the...Leave a comment:
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Thanks Eazy. I removed the capacitor from the board today and it does indeed read as open, as R_J said was a common failure up above. For reference, the information on the side of this specific capacitor are "MMKP82", 1KV 333 J 1910. It is indeed the capacitor at board location C614A. There's no visual external indication (bulging, etc.) that the capacitor has failed.Leave a comment:
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I also am in the process of repairing a very similar TCL. Mine is the 75S425, but from what I can tell they use the same power supply. I replaced all LED strips today, as many of my previous repairs of various TVs have almost always boiled down to that, however my set is still dead in the water. Flashlight test shows the Roku boot up screen and I get key-press sounds, so mainboard is good it would seem. [USER="112742"]triplefour[/USER] please do post back if you're able to locate a suitable replacement capacitor for c614a, and if swapping that out does indeed fix the problem. I've noticed...Leave a comment:
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Re: Panasonic TC-P65ST50 plasma vertical black section repairable?
That's too bad. Time to part it out for ebay I suppose. Thanks for the feedback.Leave a comment:
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Re: Panasonic TC-P65ST50 plasma vertical black section repairable?
Has anyone had a similar problem or have any insight on this repair?Leave a comment:
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Panasonic TC-P65ST50 plasma vertical black section repairable?
Hello,
I've acquired a 65" Panasonic TC-P65ST50 for free from someone while purchasing another TV for repair from them. I've repaired ~10 LCD TVs over the years with decent success, and I enjoy doing it. However this is my first attempt at a plasma, and I'm treading carefully.
The TV when I got it would power up, however the left ~5 inches of the display was entirely black, basically like a letterbox image would appear. I disassembled, looked up some info, and determined that it was likely either dirty/loose connectors between the panel and the C buffer boards... -
Re: Partially repaired Vizio E701-A3, need help!
Has anyone had a similar image on their 60 or 70" Vizio model to this? Was a new t-con sufficient to fix it or is this one toast? I plan on ordering one more "new" (according to ebay) t-con board, which I'll just return if it doesn't fix things. I'd love to hear if anyone else has been at this specific point and what the outcome was.Leave a comment:
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Partially repaired Vizio E701-A3, need help!
Hello everyone,
I have an E701-a3 (notoriously risky) that I picked up for $50 with no mainboard (I don't know the backstory very much, the people that sold it weren't too talkative so I don't know much about how it ended up in that state.).
So, bought a replacement board on eBay, hooked it up, and ... TV powered on to lit black screen, but no output on the TV. Did some research, and of course came across the large e701i-a3 thread here: [url]https://www.badcaps.net/forum/showthread.php?t=49281&highlight=e701&page=47[/url]. I've read that entire thread, and... -
Re: e701i-a3 no picture but backlights
Has anyone got any of those tiny COXA chips left that they're not using? Bought a T-con board, disconnected the bottom left 3/4 ribbon cable as instructed, got a partial picture (all distorted lines as the TV booted up) powered it off, checked panel resistance on following the video from post #916 or whatever it was, panel seemed to check out as ok on both left and right sides. Plugged it back in carefully and back to just the black lit screen with no booting. Chip on the tcon before installing was reading like 2.1K ohms on the bottom left...Leave a comment:
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Re: 55 lg model 55uf6450 no backlights
Just for the sake of anyone down the road, I bought a replacement main board and the TV is working great. Before I decided to buy a replacement, I tried baking the board in the oven to possibly fix any solder joints (375 for 10 mins). This actually brought the other board back to life, but only lasted about 10 minutes and fizzled out again. I tried baking more (400 for 15 mins) and got about 10 more mins out of it. Either way I knew that back lights, psu board, T-con, and cables were all fine so I felt like there was low risk in replacing the...Leave a comment:
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Re: 55 lg model 55uf6450 no backlights
Nick,
Thanks for the information. That's what I was afraid of. Is there any point in me trying to oven bake the board to reflow the solder? That method seems somewhat suspect to me, but if it works, it works, I guess. A lot of people report success on their LG repairs doing that.Leave a comment:
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Re: 55 lg model 55uf6450 no backlights
Here are the pics you requested. I listed the voltages observed in a previous post, but I can measure and post them again if that's helpful. Let me know what I can do to test....Leave a comment:
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Re: 55 lg model 55uf6450 no backlights
Is there any further troubleshooting I can do at the main board to see why it's not sending a 3.3v DRV-ON signal back to the power supply? Is it safe to jumper (with a paper clip or length of wire) the 3.3v signal from another pin on the plug to the DRV-ON pin to see if the backlight is working? Is there any sort of hard reset on the board itself I can perform? There are two tactile press and release buttons on the main board itself, what do they do?Leave a comment:
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Re: 55 lg model 55uf6450 no backlights
So I guess the 'DRV-ON' pin that changes from 0v to only 75mV is the problem. That should be coming back with 3.2 or 3.3v when fired up, right? Does that mean a failed main board?Leave a comment:
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Re: 55 lg model 55uf6450 no backlights
Well....... Just realized there's a second row of pins under the first line of 6. D'oh. Measurements on that line from top to bottom are 3.37v, 0v, 13.3v, 13.3v, 13.3v, and 3.38v.Leave a comment:
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Re: 55 lg model 55uf6450 no backlights
There is no voltage spike that I can detect with my multimeter on any of the 4 led +/- pins as power is turned on. Also I measured the pin outs to the main board again because I think the 5th pin down should have 13.3v while turned on, right? I measured again carefully and I am definitely NOT getting any voltage on that 5th pin at any time (on or off). Perhaps that's the problem?Leave a comment:
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Re: 55 lg model 55uf6450 no backlights
When measuring the led+ and led- (both sets) when the TV is plugged in but not turned on yet, I get about 62v on both of the LED+ pins (and like 0.20V on each led- pin) when I press the power button, led+ jumps to about 90v right away then rises slowly to 121.8v over perhaps 8 seconds or so. I read 121.8v, 2.0v, 121.9v, and 1.98v across the led pins.Leave a comment:
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Re: 55 lg model 55uf6450 no backlights
Ok, when measuring the pins shown in the picture attached (with the table showing voltages included) I get 0v, 0v, 8.85v, 8.87v, 0v, and 0v. When I press the power button, I get the following: 75mV, 0v, 13.26v, 13.25v, 0v, and 3.38v....Leave a comment:
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Re: 55 lg model 55uf6450 no backlights
Yes, I have a multimeter. I'll do as you suggest in post #9 and let you know the results.Leave a comment:
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