Re: LG LED 60LS5750 No Picture but Backlight OK
I got one of these with no picture, and the guy I got it from had a cracked screen one with all the cards. I changed the tcon and it worked again for about 2 months. Now it is randomly getting lines through the screen after it heats up. I believe it to be the same issue, since lg has issued a new replacement tcon for them. Unfortunately, those of us with non-warranty tv's we will likely have to wait. There is someone on ebay selling refurbishments. He wants your core, then he sends out a fixed runtk version back out to you. I would...
Worminizer
Telephone Guy
Last Activity: 03-10-2014, 01:59 PM
Joined: 08-19-2012
Location: Orlando, FL
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Re: Vizio VW37L HDTV20A Power supply No Standby Voltage
Ok, I reread the whole thread, since its been a while, and I looked at what retiredcaps had said,
2) A fluctuating voltage suggests one of the following
a) the startup cap, c213, is bad (the small ones rarely bloat)
b) the SMPS IC is bad
c) there is something shorted on the secondary output side (like a diode)
3) The SMPS IC needs stable DC voltage in order to work properly.
I began looking at the diodes on the board, and found one that isn't shorted, but it's wide open,...Last edited by Worminizer; 10-17-2012, 04:25 PM.Leave a comment:
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Re: Vizio VW37L HDTV20A Power supply No Standby Voltage
Ok, I got my bridge rectifiers in, I threw one in, and remade my own inductor. I re-wrapped the magnet with new wire, and actually made it new again. Everything is back to where I was before I oopsed. I also changed out both of those capacitors with new low esr ones, though neither one tested faulty with either a capacitance tester on the fluke, or the esr meter. I still get 0v on the 5v rail. What would I check/replace next? Should I order a new controller IC?Leave a comment:
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Re: Vizio VW37L HDTV20A Power supply No Standby Voltage
thanks budLeave a comment:
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Re: Vizio VW37L HDTV20A Power supply No Standby Voltage
Could you help me distinguish which bridge rectifier I should order from digikey? I have looked, and there are over 2000 to choose from. I am just not that familiar with the devices to know the difference. Here is the datasheet, it is an 8k.
[url]http://pdf1.alldatasheet.com/datasheet-pdf/view/291989/SHINDENGEN/US8KB80R.html[/url]Re: Vizio VW37L HDTV20A Power supply... are over 2000Leave a comment:
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Re: Vizio VW37L HDTV20A Power supply No Standby Voltage
I will be doing just that.Leave a comment:
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Re: Vizio VW37L HDTV20A Power supply No Standby Voltage
by the way, I took a good portion of the shock myself. I'm pretty used to getting hit at work by leaning my arm against an array of T-1's, Ringing generators, and power feeds, Stupid I know, but its a good reminder to be careful, because there are more hazardous voltages than just 120vac in a tv set.Leave a comment:
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Re: Vizio VW37L HDTV20A Power supply No Standby Voltage
oh, good, I'll get a new rectifier and see if I can get it back to life then. I have a few power supplies laying around. I will see if there are any rectifiers I can scavenge.Leave a comment:
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Re: Vizio VW37L HDTV20A Power supply No Standby Voltage
The short goes away on the non feed side after the bridge rectifier is pulled. It remains, until the inductor is pulled. After that its all ok, so there are at least two troubles in components.Leave a comment:
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Re: Vizio VW37L HDTV20A Power supply No Standby Voltage
250k ohms declining.Leave a comment:
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Re: Vizio VW37L HDTV20A Power supply No Standby Voltage
I forgot to mention that I already did pull them out. The bridge rectifier should in diode mode read as bridged diodes should it not? It looked good from the first pin to all the other pins(short in one direction only). when I tested from 2-3, 2-4, 3-4, they all showed short in both directions. Is that normal? I pulled the bridge rectifier out and still had short on my feed. I then pulled the inductor on the right, and the short went away on both sides. I tested the inductor out of circuit and all 4 leads are hard shorted....Last edited by Worminizer; 10-08-2012, 08:12 PM.Leave a comment:
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Re: Vizio VW37L HDTV20A Power supply No Standby Voltage
I found three things I need to replace before I continue. The bridge rectifier is shorted between 3 of the 4 pins. Both chokes look terrible, though only one measured shorted. The one on the right has both phases wrapped together and the insulation melted, causing a short. The one on the left doesn't read as short, but thats only because the phases don't come into any contact with each other. The insulation is badly melted on that one too, therefore causing each side of the windings to short in line, thus causing less windings....Leave a comment:
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Re: Vizio VW37L HDTV20A Power supply No Standby Voltage
meh, I'm not really doing this to save money. I'd have to fix it pretty quickly to make it cost effective to try and fix on component level. I do it to learn. If I get to a point where I get super frustrated, and just can't move forward, I will buy the board.Leave a comment:
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Re: Vizio VW37L HDTV20A Power supply No Standby Voltage
Ok, guys, I will probably be a while. I flipped the board over while it was still connected and arced it. It fried the power strip, and blew the main fuse. I've replaced the fuse, and it keeps blowing. I have to figure out what I destroyed now, before I can continue. I have a hard short between the two ac feed legs.Leave a comment:
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Re: Vizio VW37L HDTV20A Power supply No Standby Voltage
I checked it again at pin one, and its going as high as 10.696, but it is fluctuating. I took a min-max and attached a photo. That looks high enough to start, but should it fluctuate like that?...Leave a comment:
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Re: Vizio VW37L HDTV20A Power supply No Standby Voltage
EA1532A
7H1W112
Hn67361
Thats everything printed on the ic.Leave a comment:
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Re: Vizio VW37L HDTV20A Power supply No Standby Voltage
ahh, ok, let me repost those using the neg leg of the main filter cap. That is the giant one correct?
1 9-10vdc fluctuating
2 0vdc
3 0vdc
4 .01-.05vdc fluctuating
5 0vdc
6 .10-.50vdc fluctuating
7 0.00-0.05vdc fluctuating
8 160-164vdc fluctuatingLeave a comment:
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Re: Vizio VW37L HDTV20A Power supply No Standby Voltage
c213 is a 68uf 25v cap, which is tied directly to pin 1, there is another cap right next to it (c208) a 47uf 50v, which is not directly tied to pin 1, but here are its measurements across both legs. .01vdc. I feel confident that it is not the startup cap.Leave a comment:
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Re: Vizio VW37L HDTV20A Power supply No Standby Voltage
I created a quasi-chassis by tying all the points on the ps board that it touches the chassis together, as well as tying it to ground. If this doesn't work, the only thing else I can think of is getting some stand offs and bolting it in backwards.
Between the two leads of the startup cap, its fluctuating between 9-10vdc.
Here are my new voltages on the ic.
1 68-70vdc fluctuating
2 79-79.5vdc fluctuating
3 78-79vdc fluctuating
4 78-79vdc fluctuating
5...Leave a comment:
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Re: Vizio VW37L HDTV20A Power supply No Standby Voltage
I can take a picture of the whole set fully assembled if you like.Leave a comment:
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