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Please upload pictures using attachment function when ask for help on the repair
http://www.badcaps.net/forum/showthread.php?t=39740 -
Please upload pictures using attachment function when ask for help on the repair
http://www.badcaps.net/forum/showthread.php?t=39740Comment
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Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else
OK So it's not the problem??
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Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else
Sorry to be distracted.. Had my TV Scrap guy come in and bring me some new toys..Comment
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Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else
ERROR!!! You should have got them to take this one away!!!
I dont trust/understand the results from your meter perhaps I will have a snooze and see if anyone else can decide if its good or bad - either way
does it have any marking on it?Please upload pictures using attachment function when ask for help on the repair
http://www.badcaps.net/forum/showthread.php?t=39740Comment
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Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else
hehehehehehe
Marking like burns or the like?? Nope... The board looks in really good shape...
It seems I have a penchant for TVs with funky voltage readings..
https://www.badcaps.net/forum/showthread.php?t=42835
That one the voltages were ALL good across the board.. Still haven't figured that one yet either. That's the one that prompted me to buy the Rigol..
I'm thinking I will just replace the power PCB..
But I really learned a LOT by going thru this one...
Thanx a bunch to all who replied...Comment
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Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else
[QUOTE=Michale32086;522819]hehehehehehe
Marking like burns or the like?? Nope... The board looks in really good shape...
Noooooo! part numbers on the D304 diode?Please upload pictures using attachment function when ask for help on the repair
http://www.badcaps.net/forum/showthread.php?t=39740Comment
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Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else
Oh DOH!!
Lemme pull it and I'll check..Comment
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Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else
Sb140a
1005gComment
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Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else
I don't know guys... if that SB140a diode has a voltage drop of 0.2, to me that is bad. It should have 0.5 to 0.7V drop. Now if that's the little diode that's next to that IC301, chances are good for the IC to be bad too. These sets are known for that to go.Comment
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Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else
We have seen that -it is one of the parts in the repair kit. My thinking was that the IC is part of the PFC circuit and as he is measuring almost 400vdc on the BIG caps then the PFC is working so it should be ok, would you/anyone agree with that?
What we really need to know is after the Big caps how the VS & VA voltage
processed?Please upload pictures using attachment function when ask for help on the repair
http://www.badcaps.net/forum/showthread.php?t=39740Comment
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Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else
There are so many things here I don't know where to begin. I know you are a beginner and enthusatic to learn, but you must have a bit of thick skin reading my comments/suggestions.
None of this is meant as malicious, only to help you. A bit of tough love.
1) When you don't know if resistance should be measured with power on or off and that your meter has a diode test function, it is back to multimeter basics 101.
You need to learn how to use and interpret readings on a multimeter before continuing. The manual is short and simple and that should be mandatory reading (yes, I read it).
More importantly, you need to know how to interpret the readings. Chapter 7 of this book
tells you the building block components. It tells you what they are, how they work, why they fail and how to test them. And yes I have read the book from my local library and it is excellent.
2) I know you have a new scope, but you should put that aside for now until you get more experience.
You should watch some youtube training videos and this one "EEVblog #279 - How NOT To Blow Up Your Oscilloscope!"
https://www.youtube.com/watch?v=xaELqAo4kkQ
3) If you are going to do more of this repair, you need a better camera with a macro mode and better lighting. You can get an used Canon digital camera with macro mode from craigslist or ebay for around $20. 4MP is sufficient. All my photos on badcaps are taken with a Canon A80.
For lighting, since you live in Florida, you have all the lighting you need outside in the sun.
4) A SB140a diode is a schottky diode.
https://cdn.badcaps-static.com/pdfs/...780a9a5308.pdf
As such, it has a low forward voltage drop (straight from datasheet). So a reading of 0.2V and 0L is okay. Most diodes fail shorted.
5) When you can't find a training or service manual for your particular TV, try the models below and above it. Since LG makes many 50PK series TVs, you would have found this training manual with a bit of looking around.
In it, there is a in-depth section with pictures, describing how the SMPS works and the sequence in which things turn on.
It may not be exactly the same as the 50PK540, but it should provide valuable clues.
6) So let's review and try to make sense of all the readings. AC detect is 4.66. You have 5V and 17V which means the microprocessor has finished step 1 (see attached pictures).
Step 2 is to turn on M_ON (around 3.28V) which supplies 3 voltages including the Va and Vs. This is the key question that selldoor has been asking.
If M_ON is not generated (i.e. 0V), then Va and Vs will be 0.0.
This is step #7 on page 49 of the diagram.
7) Note there is a way to turn on the power supplies automatically, but requires a load to see if the SMPS is good and the main board is suspect. This is described on page 48 under the AUTO GND section.
8) I'm not a plasma expert at all, but all SMPS and main board interaction work more or less the same for any consumer electronic device.Attached FilesLast edited by retiredcaps; 01-21-2015, 03:21 PM.--- begin sig file ---
If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.
We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.
Please do not post inline and offsite as they slow down the loading of pages.
--- end sig file ---Comment
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Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else
Not a problem whatsoever, RetiredCaps.. I know that my ignorance is only surpassed by my eagerness to learn.
I'll review all the links and am downloading the manuals right now..
Just FYI, there is 0v on M_ON when the unit is plugged in...
Thanx again for all the great info and links..Comment
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--- begin sig file ---
If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.
We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.
Please do not post inline and offsite as they slow down the loading of pages.
--- end sig file ---Comment
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Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else
I meant to write
"Pop quiz, hotshot." What does that tell you?
From the movie Speed starring Keanu Reeves.
--- begin sig file ---
If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.
We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.
Please do not post inline and offsite as they slow down the loading of pages.
--- end sig file ---Comment
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Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else
There ain't hardly ANYTHING in this world that can't be addressed with a movie quote!!!
As to what it tells me??
It tells me that I need to study those manuals...
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Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else
OK, looking at the diagram is a lot tougher than reading the process on page #50..
But one thing confuses me. Well a LOT confuses me, but one thing stands out..
The page talks about plugging in and powering on.. With this particular TV, they appear to be one and the same..
So, I am going to assume that they are the same, as when I plug the TV in, it appears to go into power up mode..
OK, as I read it, then the TV is powered up, the Microprocessor IC701 is energized and sends a signal (5v) to the RL-ON.. I think I am getting that.
The second signal by IC701 is sent to ML-ON which I am NOT getting..
So, based on that, I would have to conclude that IC701 is wanky..
Howz dat??
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Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else
Ahhhhh I think dawn has broken!!!
The problem isn't the SMPS Power Board..
The problem is in the Main Board!!!!
Well, I'll be deeped in sheet!!!Comment
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Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else
Bomb on board?
Dont travel by bus?
Thanks retired caps I MAY have got there in the end.
Michale - what is the part number of IC701 ?Please upload pictures using attachment function when ask for help on the repair
http://www.badcaps.net/forum/showthread.php?t=39740Comment
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Hello,
I have been reading a few threads on here regarding Panasonic plasma tv's. I've found one thread which explains the same problem as mine, unfortunately the thread has not been completed.
I got a free tv (TH-50PX8EA) from a friend which shows no screen. When plugged in only one red light shows up and when pushing the ON button, the red LED turns of and will only turn on again when pressing the ON button again.
When plugging in the TV i hear two relays click fast and after a few seconds the third relay clicks.
I have measured the voltage in the VSUS line, which...06-18-2024, 12:58 PM -
I got this TV a little over a year ago from a coworker from my previous job. It’s a Samsung 46” TV, model number LN46b530p7f.
Problem:
Backlight cycles On and Off.
Basically, when the TV is turned On, there is a relay click heard from the TV PS board. The relay cycles On and Off 4 times in about 2-3 second intervals. Each of those 4 times, the backlights also cycle On and Off with the relay. The screen TFT isn’t cracked/damaged and appears to work - I can see a “no signal” image when the backlights turn On briefly – though the image is a bit dull/dark.... -
Hello
The red and green LEDs both light up and you can hear the relay click. (no picture, no backlight, no sound)
2-3 seconds later the relay will click again and only the red LED will stay on.
I would be very grateful for any advice or a little help.
circuit diagram?
Thanks very much -
Hi, I'm seeing one 9V relay having temperature 40C on its 9V (primary) side. Does that seem right? I switched 2 relays on that board and the temperature was the same (on the same position), so I'm sure it's not a faulty relay. I measured voltage on that relay and it was 9.5V DC, so that looks good. I don't see any other relay on that board having that kind of temperature and they have 9V on them too.
I thought maybe the transistor that is switching this relay keeps switching on/off, so I also checked for AC and there was almost none: 0.3V using mV range. No steady frequency was shown, but... -
Hi everyone!
I have this board that suddenly stopped supplying power to an output that drives an interchanger cleaner motor.
I checked while the board was in place with all wires attached and there's no AC voltage on the corresponding plug X5
This X5 is driven by fuse F8 (tested OK) which comes from the second orange relay
To make sure there are no charcoaled contacts inside the relay, I got a 24VDC power supply and got it ready to manually power up the coil side of these relays.
I respected the polarity, positive to cathode of protecting diode
So provided all...
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