Re: Another LC-80LE632U 2-5 thread
Yes, Tcon was shorting out 12V
I had it hanging out last night with a 65" plasma with pretty good results. I would say the smaller images (like a face in the distance) isn't as clear on the 80" LCD as it is with the 65" plasma. Almost like it was a little out of focus. This is from 12' away with both screens showing the same scenes.
Football looks great so it's going up on the wall today : )...
jacksnife
Member
Last Activity: 02-06-2016, 06:15 AM
Joined: 01-29-2016
Location: Frisco
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Re: Another LC-80LE632U 2-5 thread
Thanks to everyone's help... Success! Wow! I would have bet the farm the panel was broken somehow.
So this is what I learned:
1) There is hope if you have the dreaded 2-5 error code
2) You will not get any backlight circuit with a shorted out Tcon
3) Removing Tcon still no backlight
4) Even if I did get a backlight I wouldn't have been able to see anything without a working Tcon. (the screen is black with the ribbon cables disconnected der!)
5) Vigorously waving the service manual at the TV and...Leave a comment:
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Re: Another LC-80LE632U 2-5 thread
Ok, got the new board in and it appears to be working... I can see the backlights working from the back. There are no codes blinking, just a solid light.
I suppose there is nothing left to do but hook up the panel now. Should I hook up one ribbon connector at a time or just go for the gusto?Leave a comment:
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Re: Another LC-80LE632U 2-5 thread
There is no Tcon board installed. I'll let you know after a good one comes in : )Leave a comment:
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Re: Another LC-80LE632U 2-5 thread
I see a few posts about OFL being 3.3V when the backlights are up. 0.55V is a suspect level. Is it an output from the Main or output from the power supply? On the power supply it goes through a 22ohm resistor straight to a pin on the IR2E67M... idk why you would want to do that unless it's part of some kind of voltage divider. There are some other resistors hooked to the line... I'll map it out later to see if it helps me decipher if it's an input or an output. Unless someone can tell me? : )Last edited by jacksnife; 02-02-2016, 01:09 PM.Leave a comment:
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Re: Another LC-80LE632U 2-5 thread
Here are the voltages I'm reading on the PS PD connector. This is in service state with Tcon completely disconnected and the backlight cables disconnected. The only thing hooked to the PS is the PD connector going to the main board and the A/C cable.
Does anything stand out? The problem I'm trying to solve is 0V on the backlight LED transistors. There is no datasheet available on the IR2E67M LED Driver so I have no idea if there is an enable pin or what's going on with it : (
...Leave a comment:
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Re: Another LC-80LE632U 2-5 thread
Freakaftr8, I have studied your backlight thread... very impressive! Not many people will take on the challenge of disassembling an 80" panel. Kudos!Leave a comment:
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Re: Another LC-80LE632U 2-5 thread
[COLOR="royalblue"]
No... I was testing the 12V regulator with the bulb. It's the 12V line that the Tcon board is shorting out.[/COLOR]Re: Another LC-80LE632U 2-5 thread
[COLOR="royalblue"]
No... I was testing the 12V regulator with the bulb. It's the 12V line that the Tcon board is shorting out.[/COLOR]...Leave a comment:
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Re: Another LC-80LE632U 2-5 thread
I think the Tcon has a bad BD81000. I hooked it to a bench power supply and it's sucking down all of the 2A the PS could source. The BD81000 was the only device getting warm.
I'm done with this Tcon board for now. I put a bid in on one from Ebay... it's cheap enough to at least try.Leave a comment:
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Re: Another LC-80LE632U 2-5 thread
Yes, the chip has over current protection built in. I tested it with a 4A load and it shuts down the same way it does when I hook up the Tcon board.
I'm getting 4 ohms on the Tcon power-gnd. It's not a direct short, but still too little to be right. I could hook it up to a non-protected 12V and see which component gets hot
I wouldn't be surprised if the Tcon and the PS AND the display are bad. If the display is bad then I'll just shoot it with a shotgun so no one else goes through this.
So, right now I'm...Last edited by jacksnife; 02-01-2016, 07:35 AM.Leave a comment:
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Re: Another LC-80LE632U 2-5 thread
I don't see an fuse on the Tcon board... i also put a load on the 12V line and got a good 2.25A out of it. When I tried for 4A the regulator automatically shuts down....Leave a comment:
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Re: Another LC-80LE632U 2-5 thread
Budm, Thanks for the help! I was able to use a 27W 12V bulb as a resistive load and it lit up pretty good. The current was over 2 amps so I feel pretty good about that one.
Can you help me get the back light circuit operational? I don't have any volts on the collector or emitter on their transistors. I'd have to unsolder the heatsinks just to see what they are.Leave a comment:
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Re: Another LC-80LE632U 2-5 thread
Yes, that's the one......Leave a comment:
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Re: Another LC-80LE632U 2-5 thread
I was thinking the same thing... the Tcon board measures about 4 ohms between the +12V pin and gnd and is dropping the voltage to 0.7V. Is my thinking right for that 12V PS to only be sourcing 175mA?
I wouldn't mind spending a few bucks to get a spare, but i'd rather do everything I can to determine if the screen is good/bad before ordering one. I suppose the only thing I can do is visually look for physical damage, so this is why I want to rig the backlights to come on.Last edited by jacksnife; 01-30-2016, 04:37 PM.Leave a comment:
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Re: Another LC-80LE632U 2-5 thread
Ok, I assume the Tcon power source is the 4 pin connector (PL)? When it is disconnected there is 12V coming from the power supply sitting at the disconnected 4 pin connector. When I connect the 4 pin connector back to the Tcon board there is 0.7V.
"probe tcon 12v output voltages and see if they briefly come up" <- Are you referring to the power supply 12V output? Or does the Tcon also have a 12V output?
Man, schematics sure would be nice! If I just had a power supply schematic I know I could figure out a...Leave a comment:
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Re: Another LC-80LE632U 2-5 thread
Ok, thanks for the help...
So considering I have the display ribbon cables disconnected I can assume the display itself is no longer influencing the fact I still have a shorted 12V power at the Tcon. It doesn't mean the display is good... but I can't say for certain it is bad until I get a known good Tcon board, correct?...Leave a comment:
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Re: Another LC-80LE632U 2-5 thread
Same result, .7VDC sitting on the 12VDC with PL connected.
Also while I was there I decided to probe on the bank of transistors. I'm guessing they are for powering up the backlight and that there should be a rail voltage sitting on the Collector, Base being pulsed, and the actual LED sitting on the Emitter. 0VDC on all of them.Leave a comment:
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Re: Another LC-80LE632U 2-5 thread
ok sorry I jumped the gun... I'll go do that.Leave a comment:
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Re: Another LC-80LE632U 2-5 thread
Please correct me if I'm wrong, but in my mind the Backlight and the LCD Panel are two completely different animals. If the display was dead it wouldn't kill the backlight (and vice-versa) would it?
So right now I have the V light on constant (no error code), I have the Tcon 4-pin disconnected and 12VDC is up. Shouldn't I be able to read some voltage on the backlight connectors?Leave a comment:
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Re: Another LC-80LE632U 2-5 thread
Ok, holding all three buttons stops it from going to the 2-5 blink state. But I never see or hear any sign of a backlight.
I have .7V on the 12V pin of PD, then disconnect the 4-pin PL connector on the tcon board and the 12VDC comes back. i.e. the Tcon is either shorting out the 12VDC, or the power supply no longer can supply enough current to turn it on so the volts drop to near 0.Leave a comment:
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