LG 50PK750 reflow again?

[x_orange90_x]

A few months ago I sold my brother in law this 50PK750 that my brother repaired. The issue was with the BGA on the main board and he had reflowed it. The tv was working great up until about a week ago when the colors started going "off" and began alternating between bright and dim.

Is this likely the BGA again, or could it be power supply related? I don't have it in my possession so I haven't had a chance to open it up yet. If it is the BGA again, is it practical to try the reflow again, or replace the main board? I found a main board for about $55, but I'm afraid of having the same issue creep up in a few months with a replacement.

[diif]

Give it another reflow before buying another board.You can also do a test with jumpers on the logic board to check if it's the motherboard giving issues.
Buy a cheap thermometer to better monitor the reflow temperatures.

https://www.aliexpress.com/item/1005003642882603.html

[x_orange90_x]

I guess I never updated this post. I went ahead and did a reflow (again!) myself and the picture looked awesome afterwards. It's been a few weeks and I haven't heard any complaints so I guess it's still holding up. I heated up the chip pretty good, especially near the center. Hopefully it will last longer this time 🤞

[diif]

Did you use flux ? What about using the cheap thermometer ?

[x_orange90_x]

No to both. My brother used liquid flux the first time, but I didn't have either of those. I did heat it to 250c for about 5 minutes going around the edges, across, and in circles.

[Davi.p]

Your tv buyer will come back soon claim for money back... not good reflow is been made, 250 celsius degrees are too low, you need to heaten all the board from bottom (check my posts around november 2020 on how to), then check the working state, clear well the area, then i suggest you seal the perimeter of the chip with hot glue, this is my last thought for an experiment, try if you want, if you want to be more sure also DRAM chips must get same treatment.. let me know how it will go..

[EazyBone]

Yea I'm not an expert but, i agree that's way too low

[x_orange90_x]

The heat gun I had was only two settings; 250c and 400 something. I followed the advice I was given for the first reflow

https://www.badcaps.net/forum/troubl...36#post1848336

I'm not worried about the "buyer" because it's my mother in law's now. Initially her son bought it from me, used it for a few months, then gave it to her. I already told her if it fails again I'll just replace the board. Thankfully this is the first and only one I've repaired that has had an issue, and because of this particular incident, I won't sell a reflow to anyone again. Many people have said that reflows are a bandaid and will eventually fail again which makes complete sense because if the quality of solder was shit to begin with, reflowing won't make it "better".

[diif]

There was nothing wrong with the quality of the solder and a decent reflow will last years. I've done plenty, and much reballing.
A half arsed job without flux though.
It's lead free and leaded solder, not shit and better.

[x_orange90_x]

There was nothing wrong with the quality of the solder and a decent reflow will last years. I've done plenty, and much reballing.
A half arsed job without flux though.
It's lead free and leaded solder, not shit and better.

Well they fail for a reason. Regardless, we'll see how it goes. I visit frequently so I'll know if/when it fails.

Do keep in mind this is my own personal "first" for this type of repair. Trial and error. My brother has done this several times with monitors and game consoles. He knows what he's doing and it still didn't hold up long.

[diif]

Yes, I'm well aware it was your first go, hence suggesting the thermometer. How else are you knowing what temperature the PCB is?

The reflow I did on a PS4 Pro two years ago is still going strong.
If your brother's reflows are failing short I would suggest he looks at improving his technique. Maybe he needs to follow the profile better which requires a thermometer.