Just to update and close the thread. New board came in and fixed the problem.
but I did fine the short. It was a tiny transistor next to the 8pin ic. Unfortunately there so tiny and I can see any markings to identify it and replace. Didn’t want to remove new boards ic since it all covered in silicone to find out.
Storyteller12
Badcaps Veteran
Last Activity: Today, 06:01 AM
Joined: 06-12-2020
Location: Virginia
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Almost all vizios I come across are bad main boards if it’s not backlights. Usually the BGA chips needs reflowing.
on a side note I don’t even bother messing with Vizios anymore. There a pain to troubleshoot and nobody really wants to pay for them anymore in my area. So not worth my timeLeave a comment:
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I don’t see burned resistor. I think it may look that way because of the silicone there. Most of that area is/ was covered in slicone...Leave a comment:
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Sorry, resistors removed and both test good with same reading.
mad for the 2 diodes dp802-3 both test good as well.
I removed that ic also and still have same symptom...Leave a comment:
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Diah, I just checked. I can’t make out exactly what it is but one side measures 12k ohms while the other side measure 2.2m ohms. I’m not to sure what that means thoughLeave a comment:
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I was looking at that IC (icp801). I will test that one today and see if I have a replacement. I’ll double check the 2 diodes but I’m pretty sure I checked those and they tested good.
I did remove the big 500v caps and they test 68uf but I don’t have esr meter to test esr values. Would an lcr meter test the esr value?
also I did replace 1 of those blue disc caps right by the diode and mosfets that were bad.
funny thing, I just tested the diode that was all burned up and black and it tested good. So only the mosfet was bad, but replaced both anyway....Leave a comment:
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I did check those 2 resistors and they test good.
not sure what else it could be.
EazyBone, I already bought that board lol but was trying to fix this one as wel. Alsol because all those 50” Samsungs with all in 1 boards has same problem. Primary side voltage fluctuates just like this. I have 3 or 4 with same symptomLeave a comment:
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Yes I found qp801 mosfet shorted and the diode right next to it. And the little blue cap right there also.
are you talking about the 2 bigger green resistors right below all the way to the left (RP822)?Leave a comment:
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UN55MU8000 Power Supply Help!!
Have this power supply that is bad. Someone else messed with it prior and couldn’t fix it. I opened it up and right away there was a mosfet bad and a Diode on the heat sink.
also a little blue cap was bad and so was the fuse.
Bridge rectifier test good
I replaced all bad parts and plugged in on my table. So nothing else connected.
fuse does not blow but voltage fluctuates on primary side from 0-65v. No power on secondary obviously. I don’t see anything else that bad. I thought maybe the power ic was and removed it but same problem. I did not replace... -
You can sometimes get these cheaper models to work with different main boards. I've had a few when a ru model would work with mu model screen.
Has to be the same manufacture though for the screensLeave a comment:
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I used a long level I had as a guide with 2 clamps for the router to keep it straight and then just hung the plexiglass off the table.
I used a bit with a roller (flush trim bit) and used the table as a guide also for the bit itself.
also make sure to protect the diffuser as it scratches very easily from sliding moving it when flat.
I used blue painted tape where the router went to project it and some towels
Hope this helps. Let me know if you have any other questions...Leave a comment:
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I doubt anyone will know for sure. I assume there are some boards that would work but it’s going to be trial an error. You may have to switch eeprom since the tcon is built into the mainbord also to get one to work.
also these KS series use one connect boxes so there is no cutouts or space for mainboard with built in Inputs etc.
If you do try let me know how it goes. I have 3 of these as well (KS8000, KS8500 and the KS9000. One of the best Samsung TVs in my opinion short of the new Samsung OLEDs.Leave a comment:
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Don’t see any on that side. Need close up pics of the other side of buffer board.Leave a comment:
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A reflow on this chip will not work. These boards need the processor replaced.
I believe Nicks TV has done a yt video on these models and the processor problems....Leave a comment:
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Never seen 2 spots that needed to be covered. You can try covering more pins or fewer pins. But honestly this is just a bandaid and not a permanent fix.
this is the downside to this kind of repair. There’s always going to be some type of loss in the picture quality. Either lines like you have or some type of color loss or both.
good luckLeave a comment:
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If I’m not mistaken these LG TVs “LF” series had problems with main boards. In particular the cpu overheats and goes bad. I don’t recall anyone reflowing one to fix it either. Have to replace it unfortunately.Leave a comment:
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Usually horizontal lines are indication of screen defect. Could be bad cap on the buffer boards also. Check all caps on thereLeave a comment:
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You can still use one remote. The fire stick and be programmed to your tv to turn on and off and control the volume and switch inputs. Or you can you the Samsung remote and control the device with CECLeave a comment:
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Just buy a fire stick or similar. Smart TVs suck in general and a stand alone device will be much better and cheaper along with no headache...Leave a comment:
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I agree, seems like all you need to be a TV technician these days is a roll for scotch tape. lol...Leave a comment:
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