Re: LG 55le5400-UC AUSWLHR No backlight
Just want to say that I came across this set as a freebie and couldn't figure it out, until I saw this posting. Went through the reflow process and 40 minutes later I have a working set. Tested for a few hours with PS4 gaming and didn't see any issues.
0S1R1S
Member
Last Activity: 09-25-2023, 12:03 PM
Joined: 03-02-2014
Location: Big Lake, MN
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Samsung Syncmaster 2494LW
Has anyone opened one of these before? I'm struggling to get the dang thing apart before even inspecting the issue. I can't figure out how to remove the stand. -
Re: Vizio E500i-B1 Backlight
Problem was the main board. After ordering one and getting an incorrect part, I received the right one, and the backlights are now working just fine. Must have been an issue in the LED driver circuitry.Leave a comment:
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Re: Insignia NS-48D510NA15 Won't Power Up
Sorry for the lack of updates or replies. I ordered a main board for $30, threw it in, and works just fine.Leave a comment:
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Re: Insignia NS-48D510NA15 Won't Power Up
How would I power it on with the main board disconnected? The button board is attached to the main board....Leave a comment:
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Insignia NS-48D510NA15 Won't Power Up
Hello all, taking a break from the Vizio I've been working on to try and save this Insignia I picked up from the scrapper.
Panel is good from a visual inspection, no apparent cracks.
Plugging in the TV gives me a solid red light on the indicator panel.
Pressing power, nothing changes.
I opened the unit up and found a very simple design. Power board, main board, T-Con, speakers, and a button board.
Power supply has ~17V on the two 16V pins, 3.4V for the STB pin, 12.8V for the 12V pins, all as they should be. But the set won't power on.
So, a main board... -
Re: Vizio E500i-B1 Backlight
Okay. I understand that the LED driver is on the main board, it's the top left section of the board there. But how can that be the cause of damage to the power boards, that's what I'm curious about.
Anyway, current status is this. TV powers on. Backlight doesn't work with external or original power supply. 15.5V is there in place of 24V on the original power board still.
Thoughts on where to go from here?...Leave a comment:
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Re: Vizio E500i-B1 Backlight
With the original power supply in the TV and no changes made at all, my friend hooked up his benchtop power supply set at 24V and injected 24V into just CN9102. Backlights came on, but they were flickering.
I ordered a replacement power board and installed it. Backlights came on but were flickering. I wiggled CN9102 and the flicker went away. May not have been correlated.
Turned the set on and off a few times, then lost backlights completely. The new power board will still power the set up just fine, but I've lost backlighting and the voltage...Leave a comment:
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Re: Vizio E500i-B1 Backlight
Okay, so here's the latest update. I ordered a 24V 6 amp power adapter from Amazon and wired it in to the 24V outputs for the LED driver on the main board. Plugged in everything else, plugged in the set and turned it on, no backlight.
Then I plugged in the power adapter, and still no backlight, even with 24V going into the LED driver.
I know there is the one 24V rail coming FROM the main board to the power board, could that be my issue now?
I would just give it up and order a new power board and main board, but that would be an added...Leave a comment:
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Re: Vizio E500i-B1 Backlight
Yeah, I made the assumption it was only a power board issue.
I'm giving up and I'm just going to wire in an internal/external 24V power supply to the LEDs and see how that works....Leave a comment:
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Re: Vizio E500i-B1 Backlight
Also, I tested voltages as I was powering up, and the 24V rail would hit 16.8V, then drop.Leave a comment:
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Re: Vizio E500i-B1 Backlight
I tried this and the voltages were still 15.5V on the center legs. On the outer legs, it showed 0V....Leave a comment:
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Re: Vizio E500i-B1 Backlight
Here's an update. The owner of the TV was impatient and told me to just order a power board. It arrived today (quick shipping) after ordering Friday. Plugged it in, plugged in AC power, and boom, it was working.
HOWEVER. The LEDs were flickering. Then steady. Then a little flicker. Then, now, they're gone. Completely. And we're back to 15.5V on the 24V rail on this new power board.
My only guess is something on the main board is back feeding to the power board and killing it.Leave a comment:
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Re: Vizio E500i-B1 Backlight
Okay, I removed connector C9101 from the power supply board. Plugged in to AC power. Forced on the TV and still only got 15.5V on the 24V rail feeding the LED driver....Leave a comment:
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Re: Vizio E500i-B1 Backlight
Yes, no matter what I do, the 24V on each connector is always reading at 15.5V.Leave a comment:
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Re: Vizio E500i-B1 Backlight
Well, lightning can do odd things. A friend of mine is going to help me look at it tonight, he has a better meter that may give more accurate readings.
Is there anything else I can check in the meanwhile?Leave a comment:
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Re: Vizio E500i-B1 Backlight
In circuit, from outer leg to inner, my meter shows .460 V in diode mode.
Out of circuit, from outer leg to inner, my meter shows ~.115 V in diode mode.
Solder joints on T9101 and T9102 look perfectly fine....Leave a comment:
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Re: Vizio E500i-B1 Backlight
I'm sorry, I'm still trying to learn this stuff. So, being in parallel, that will increase the capacitance, I understand that, but why would the measurements be jumping around when they were out of circuit? I failed to mention that I removed those two from the board before checking them. So, either they are reading oddly, or my meter is junk.
Also, what exactly is esr?
By the way, before I forget, I really very much appreciate all the help! This community is great and one day I hope to be able to give back with my...Leave a comment:
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Re: Vizio E500i-B1 Backlight
Do I need to remove the diodes before checking to get a proper reading? I think I tried that already the other night and they weren't shorted.
C9131 - Reading is all over the place. From .033 to 7 nanofarads.
C9132 - Same thing. May have an issue with my meter
Having trouble getting a reading on the ceramic capacitor C9116 in circuit, so I removed it and measured it at 47 nanofarads.
Really all I had time to dig into tonight. Girlfriend getting angry I'm working on our anniversary....Leave a comment:
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Re: Vizio E500i-B1 Backlight
I have to have CN9101 plugged into the power board to the main board or I won't be able to power up the TV. So I tried that. Still the same, 15.5VDC on CN9102, all 4 connectors....Leave a comment:
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