Takeatry
Member
Last Activity: 12-12-2024, 08:09 AM
Joined: 07-23-2024
Location: Racine wisconsin
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I was about to put my tv in the box and put it on the shelf but decide to do a little more investigation. Then I also noticed this post. I did a closer inspection of the back side of my MB. In the area under the cpu chip there were what I thought were burn marks on what looked like a cap. As I looked closer I noticed the darker components are probably not caps. I did take the time to do some measurements on that actual caps in that area. I noticed 2 of them beeped on the continuity test both sides to ground and one did not. Measured the 3 larger ones. 2 of them were under 10 ohms in both directions... -
I appreciated and understood your warning. I had nothing to lose but time, which I have plenty of. It was interesting to make the attempts and learn something new. Almost felt like I was in school again.
Thanks to all the forum members that tried to help.Leave a comment:
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Was able to borrow a heat gun capable of reaching above 250C and had an adequate thermal couple. Spent a few dollars on proper flux that I could place around the edges of the chip with a syringe. Read the guidelines and YouTube videos on the reflowing process. Protected the board with layers of tin foil. Got the chip up to 250C for 60 seconds. Let it cool and reinstalled it. No help. Same exact reading of voltages. Tv shut still shut when I touched the lead on the x424 chip.Leave a comment:
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Still not quitting. Did some voltage testing on MB. Found something interesting to me. Picture below shows a chip. Looked for a long time to identify numbers on top but found nothing. I got clear reading of the voltage on all the pins, but when I touched the top right pin the tv shutdown for a short time. I repeated the sequence many times same result. I disconnected the lvds, the voltages did not change and the shutdown also occurred. When the unit shut there was a short booting period. The back lights came on quickly but the standby led blinked 3 times for 5 periods. Does the add any infoLeave a comment:
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Not quite ready to quit on this. I have already started researching my next tv. Which hopefully go on a big sale on what we call Black Friday in the states at the end of November. Since I have nothing to lose I thought I would risk taking some voltage measurements on the smaller components of the buffer panel. After not reading anything other than low 20mV any where on the panel, I was surprised to see 3.3V on the Winbond chip 25q32. I also saw the 3.3v on the diodes T15 and T16. It appeared 3.3 was on every pin on the diodes other than ground. I saw a previous post with similar testing being...Leave a comment:
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Ok hopefully the forum will indulge me with a few more questions before I put this thing back in the box and on the shelf. I know I have an option to try a different MB but at this time I won’t go in that direction. That being said have the recent measurements of fuses and inductors indicated the board is ok or are there other testes that can be performed?
There was a situation that I put on my original post that I did not a response to. Maybe a dumb question. As I checked all the capacitors I saw every one had one side with a path to ground check with the audible continuity setting. All...Leave a comment:
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I have to apologize, I think my mind is going bad fighting with this thing. The fuses are not blown. But the measurements at the inductors are correct. Does this change anything?Leave a comment:
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I think once I moved the ribbon cable between the panels with the unit on. That was some time ago and I think the tv came shortly after. Maybe I put the meter probe somewhere I shouldn’t have.Leave a comment:
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Put the board back in position? Power on but lvds disconnected? Wire already there got folded underneath when i pulled the board to remove the heat sinkLeave a comment:
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A week or so ago the tv came in 2 days in row with no masking but the jumper wire attached. I kind of jumped into an active thread to ask if the jumper wire could remain or needed to be removed. Diah responded that the wire was for diagnostic only, so I removed it. Not long after that was the period where the tv came in 4 days in row, with no wire and no masking.. Today I checked the cables as best I could for damage, both the lvds and the jumper between the panels. Could not see anything. I reattached the jumper wire and removed the ribbon from the right panel. No difference just the same 20mV....Leave a comment:
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I been looking at the threads for a few months and have learned at lot. I think I understand the last post. I removed the lvds cable and turn the unit back on. Guessing with the cable removed the signal to try and restart is not there so the SoC won’t keep trying to start and heat up. I tried it and the temp went up to 175F but not further. I would assume this is a clear indication of the shorts in the panel are the problem. I have been using the tape method and trying to check capacitors and clock signals for many weeks. I did not want to give up because the tv at times started and worked....Leave a comment:
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And this is because of the short or shorts on the panelLeave a comment:
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Would I be reading higher voltage somewhere? The most I get at the panel is 20mV....Leave a comment:
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I removed the heat sink from the main board. The main processor chip got over 200deg F. In less than a minute. I don’t have the tools or expertise to change or reflow the BGA. Guessing I’ll try a new board.Leave a comment:
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A new development. I was doing some voltage measurements at the tests-out 0,1 and 2 by the cofs from both panels to see if there were differences. I found none. So I shut it down for a while. When I turned it back on the loop was gone. Unfortunately so was the picture. The back lights were on I measured the output of the PS and still steady 13v. Did the standard removing the ps cable then the ribbon from the main board. Back lights came on stayed on. Reinstalled the jumper on main board removed the ribbon between the panels. No picture. Did the soft and hard resets no picture. Reconnected the...Leave a comment:
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That would be great. As I was going through multiple test on the panel I measured the voltage on all the test point on the right panel in the same clock signal area. The VGH was 25v and VSS was 6v all the clock test points also measured 6+v. Did this occur on the unit you are working on?Leave a comment:
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I have a QN50Q with the same boot loop issue. I started a post but it seems to have run its course. I narrowed down the problem to the right side panel looking from the back of the tv. I have been reading and reading many post regarding the issue and came across this. If I understand the testing procedure correctly I remove the ribbon from the main board to the panel and in my case the flexible jumper ribbon from the right side panel. Checking resistance on all the test points by the clock signals on both sides. My meter only goes to 50M ohms. I get the 5k ohms on the VGH point on the left and...Leave a comment:
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As expected when I turned the TV on the next morning it stared the loop. I am in the process of ordering a new DMM. I did pull my analog meter apart and cleaned all the contacts. I was able to measure high resistance across C02 7000 ohm. Checked it on the x10 setting and x1K and the values were the same. Also used the AC setting to check my thermostat, which read correctly at 24vac. Found no AC across the cap with tv running. I don’t have the expertise or equipment do do a proper analysis of a TV, but I try to use common sense to see where it leads me. I put the common lead on the metal frame...Leave a comment:
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