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- เผยแพร่เมื่อ 10 ก.ย. 2024
- A surprising fault in the 4K LG Dumpster TV.
Using the block diagram and schematic to track down the likely culprit and reflowing the BGA's in an attempt to fix the fault.
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I'm going to send you some flux. You clearly do not have enough. :'(
Don't delay...
@Louis Rossmann : Don't delay, send it today :-)
Good advice from the Flux-Man himself!
He used about 1/10 of a Paul of flux
This job probably needs about 4 Paul's of flux since it's a bigger board and bigger chips
Amateur mistake, but no worries, I've done it too. Never poke huge BGAs like that when heated. The pin pitch is very small, and you're almost guaranteed to form solder bridges. Watch out for the board warping temporarily from heat too. That in itself can cause solder bridges to form, or it can cause other BGA chips to lose connections. The board needs to be supported so that it remains flat when heated. Flux will NOT "undo" solder bridges. The surface tension will keep them together due to the small pitch. As long as you didn't short power to data, no damage should be done. This is generally unlikely anyways since power and data pins tend to be far apart for integrity purposes.
It will have to be reballed. It's not difficult to do, unless the ball pattern is something particularly weird. Since you've killed it already, just heat+lift the chip and take a look at the underside (you can take tweezers with L-shaped ends, bend the tips slightly so that they grab onto the chip's edges, and this way you can lift evenly/vertically). Make sure you do so with minimum "pulling", since otherwise you can rip out pads. Measure pin pitch (since that's difficult, you can just measure the distance between 10 balls and divide - less error that way), order a cheap stencil from eBay along with some solder balls, get some proper BGA flux (I use Kingbo RMA-218 which works very well and doesn't stink) and watch some tutorials. :) Do this not because you need to or because it's financially sensible, but just to have the experience so that future situations become simpler to deal with. How can you be the #1 electronics blogger without at least some successful experience reballing chips. Come on Dave! :) :)
I +1 this.
Has he never seen @Louis Rossmann work ?
Dave says that he has fanned out huge BGA packages at Altium, then why does he ignore the known fact that the pitch is tiny ?
E: I think the attitude of "No script, No fear" is biting him in the arse.
Recently, on the calculator video, he was very mumbling. I think the reason for this could be
1. He wanted a quick video out, so did no do itsy bitsy research
2. He is moving the lab, it has occupied a lot of part of processing power of his brain...?
3. The power capacitors of his brain are now old and puffed, may need replacing ..🤣
Excellent advice. BGA rework is just hard! ;)
@@xMalhardeshmukh I'm pretty sure Louis and Dave know each other, and I assume they've seen each other's work (Louis has mentioned him before). Dave knew he made an error here and I'm sure he knows how to reball it, it's just something he probably hasn't done in a really long time so has apprehensions about it (and it's not easy unless you are well practised)
We can't do it ALL now can we. :) :)
Yes I know. that was sarcastic .@@schr4nz
Don't give up, try reballing yourself, audience wanna see continuation Dave.
Looks like a job for paul to me!
Some people admire Elon Musk, I just admire people who are able to reball BGA chips on daily basis...
thats what i am going to comment.... 😁
Such a video might get banned… o.0
How does one reball oneself?
When I worked at Nintendo at Kirkland, we had all the kit; Mantis microscopes, fancy Hakko soldering stations, air-pencils, vacuum rigs...you name it!
One bit of training they did was to allow folks to bring in dead consumer electronics with an eye at fixing them in the shop.
Get in a lot of practice working on other peoples mistakes!
A buddy brought in an LG TV, and over the course of 3 months every dang IC and transistor had been flowed off the PCB, cleaned, examined, put back on wrong, removed, broken, replaced, put back on right, you name it!
In the end it was a partly shorted by-pass capacitor...swollen electrolytic, nobody saw it!
Check yer basics first!
Working at Nintendo... I would love an old 2DS motherboard schematic... Have one here that doesn't power up (LED goes blue, stays few seconds, slight pop and turns off), can't find the fault to save my life. Not the screen having bad connection, nor screen itself (tested even with another 2DS screen).
That TV seems to have been molested way past repair point... Did you guys manage to fix it in the end or did all the molesting kill too many ICs inside to make it possible?
IT'S THE DECODE ENGINE RAM!!! It HAS to be either that or the decode engine in the main chip itself - thats where the signal is being blocked. The signal is fed from there to the [B] Engine block which handles the OSD etc and clearly is working fine. The decode engine and the [B] Engine have separate DDR3 controllers, so the ram fault isnt affecting it. The display output looks like classic VRAM issues. A RAM fault is also vastly more likely than a processor fault
Mijc Osis Yes... It is not even Samsung RAM..
nothing is being decoded when you play HDMI source
but yes it can be ram for en.wikipedia.org/wiki/XD_engine
Well even if it is the ram, now it has more than one fault, oops.
My thought as well, GUI memory/frame buffer is ok, but not the memory/frame buffer for the video decoder.
I was thinking the same. But now it's significantly harder to be sure.
I think the issue is quite obvious: You didn't use enough flux! Check out Louis Rossman to see what an adequate amount of flux is.
Yeah you need at least one milliPaul of flux, that's like a microPaul or something. Totally inadequate.
Its 2 parts flux, 1 part PCB.
The bigger the glob, the better the job.
@The Dollar Guy
Is that by weight or by volume?
@Dave Micolichek pretty sure he doesn't get along with Louis Rossmann either :P
for those who don't know, chris gammell is his co-host for The Amp Hour, a podcast about electronics
@@Dead_Ringer They only recently met in real life, having done the podcast for years and years.
Service flow chart: Abnormal display ----> place in dumpster.
JohnAudioTech More great surface mount garbage, modern electronics is sure going down the $h!utter, no quality, hard to repair.
The right bga stencial solder paste and whit the stuff he have tv can be alive again or just ebay the pcb for like 50€ you can find the pcb and new tv.
IF the panel is ok the repair worth on 4 years old or less tv.
Then some guy comes along
"oh look, a tv. I wonder what's wrong with it ???"
@@scottb721 Or not, because if you're a nice person you'll write on it what's wrong with it!
or give to Dave Jones.
Come on don't give up.
I'm not sure if your name falls between 3.11 and 95, or if it's still to come...
phones without ir blaster work just fine.
get the IR code as a pcm wav / audio file, hook up a ir or even red led to the 3.5mm jack (if you got one lol) and play the file. i entered my lg tv service menu this way many times.
Does it really have enough power and voltage to drive a LED? What can the jack do?
ur phone sucks my phone has ir
a red / ir one of course, their Vf is right at the peak of what a headphone jack can deliver (note: amplified headphone jack not just line-out which is just 1 Vpp).
the led isnt running at much power, a red one is barely lighting up but its enough for the sensitve ir receivers to detect it when holding it like 1cm infront. certainly less than what most headphones require.
link to a write up or something?
does phone amp has enough output power / frequency response at 38 KHz for IR ?
openlgtv.org.ru/wiki/index.php/Access_hidden_service_menus_/_modes#Simple_improvised_home_brew_IR_transmitter
Dave, would you like to go for another round, may be re-balling the chip. Don't give up
Some initial tests for BGA would be applying pressure with your finger while TV is on and looking for any change in picture, cooling and or heating chip when TV is on looking for a change in picture. When attempting reflow look at near by soldered components for any solder melt which would indicate that the BGA is also melted instead of touching chip for movement.
COM port is for interfacing with an component controller. (Home automation type stuff.)
Ah, thanks.
and the protocol is an ask and answer type thing... so you have to know how to initiate comms!
Good to see Dave come a gutser every now and then. Makes me feel a little bit better.
It's the decoder RAM, because you have image movement, it's communicating but reading/writing wrong bits. But I think you toasted it, these operations must be temperature controlled
Well reflowing that chip, changed the output... So either you fixed something partly, or you just broke it completely and the error was actually before that chip, and because you broke it you didn't even get far enough to encounter the original problem.
Let me shed some light as to why the RS232 Codes are listed in the consumer manual. This is a former top of the line, home cinema TV. Most professional and home made installs for home cinemas work with universal remotes who send RS 232 codes via wire to devices such as the amplifier ,tv , screen and sometimes even curtains and such. Hence these are included because the consumer really does need them. I worked in a small scale cinema (1 screen) for about 5 years and we used this system.
Exactly. Well said.
Why, then, does it have built-in speakers that don't look removable?
Reball it! You can listen to Tom Petty's "Re-balling" to pass the time while doing it.
That's *LEAD FREE* solder for ya!
That is a high spec tv and worth fixing being only a few years old and comparing it to current model tv's (4K res, 200hz refresh rate, LED localised dimming, decent built in sound for a tv), so even if you have to buy a whole board to get it going after a couple of vids of you trying to fix it with what you have it would be worth it. RRP was $4599.00 when it left the market, average sell under $4000.00. brand new main boards available on ebay for $588.00 and $22.00 postage from melbourne. probably sell it second hand for $1500 easy once fixed if you could not find a use for it at home. i am a video junkie and i also sell TV's for a living and I would be more than happy to have this as one of my tv's.
I think you meant the video decoder. The encoder would be for recording stuff, decoding is what was to be done to view video encoded in codec x.
the instant he tapped that chip a little too hard, I was like "it's f**ked". good try tho. time to find a reball stencil
I'll cast another vote for a Dave Jones Loius Rossman shared universe! But yeah shipping between these countries is either super slow or super expensive.
my money is on that black ram chip
thats racist!!!4444
Looks an awful lot like an GPU with failed GDDR so i would suspect the RAM of either U14 or URSA9
Yes really want to see it alive and kicking again working 100%, don't give up !
Aw, poor BGA has it's balls all mixed up now :(
Too bad shipping to the states would cost probably as much as the TV itself, I like the "ship it to Louis Rossmann" ideas. It'd probably be an interesting challenge for him..
Be careful with "not used before" flux. The little bottle of flux that i bought at an electronics store not too long ago IS CONDUCTIVE!
Sure, it's a couple kOhms but i don't want it between the gate and drain of a FET in a switching power supply. Little IC's don't like to be powered with 325V DC.
it was only 784 ball chip. just reball and test :)
I don't see ads because ad blockers.
Do you have Adblock on the LG TV app?
That's great for your computer. But when you're watching TH-cam on your phone or smart tv, that doesn't work. Most purple watch TH-cam on their phone. Usually the only people who watch TH-cam from a computer are people who work from home or don't have a job.
@Andrew Delashaw For mobile, use "TH-cam Vanced". All the benefits of premium without having to pay google.
Watch some ads. It won’t hurt you!
@@xenonram I don't use the youtube app on my phone or tablet.
Ad blockers work on phone, tablets if you use a browser to access youtube. :)
Here I am 2 years later, watching this EEVblog episode and TH-cam break for commercials. The commercial was about LG OLED TV :D. What are the odds :p
Wow. LG being great.I guess you might have gotten this board to work if you had studied bit more before doing stuff for it. That garble pattern was oddly specific and might show up in troubleshooting of panels in general. I dont think reflow would have helped here.I also had few panels to fix a while ago. Could not do anything because the backlight crumbled into pieces when touched. Had no idea how to give it new light that'd match the panel.
Henri Tuhola Just seems like bad graphics RAM where the decoder / framebuffer is working.
Try putting the TV in "game mode" and see if it works. Game mode is made to reduce input lag by bypassing post-processing of the image. The game mode might bypass the defective video decoder section of the chip.
I used to reflow BGA for phones, flux is a must, and the trick is to lightly bump the corner of the chip to know that it's reflow-ed properly
Time to call Louis Rossmann
Paul daniels is somewhat local and might venture outside the apple ecosystem.
to dump more flux on it!
They include the serial commands in the consumer manual because they are used by AV system integrators to connect and control the display via a control system such as Extron, Crestron, AMX, Control4 etc. They wouldn't put it in the service manual since those are rarely shipped with the unit and are not always available online.
You need a unit with a smashed panel..Cheap
Not that cheap
unless he's really hurting for a TV, might be better to offer up his working panel on eBay for someone who has smashed theirs
Does Dave sell anything?
@@Sharklops imagine the postage price for this absolute unit
@@Sharklops Not sure how he calculates his cost per hour of work (for a TH-camr it's likely: work as much as possible while fitting everything else in your schedule and receive a huge variation of revenue), but a few days of work is probably not worth the cost of a TV for him, unless he receives revenue greater than the value of his time spent on this. Not sure, but it doesn't seem like he would save any money by spending the time on it.
However, there's the fun factor and if he wasn't going to be productive anyways, then it's worth it! I would personally do it for two reasons. 1) I don't have a 4K TV at the moment and 2) there are times during the weekend where I don't want to be doing my job but don't mind working on a project.
Those service manuals assume board swapping. The days of narrowing down a particular component because of the service manual are gone. You have to use your instincts. The original problem looks to be like a video codec problem - something probably related to MP4 video since the problem only occurs in video streams. So whatever chip handles the codec for MP4 - that would be my target.
Hi Dave. Thank you for sharing this with us. You could have scrapped this edition and we would have been none the wiser. Instead, you chose to share it, "oops!" and all, and I applaud you for that. It takes courage and a strong sense of confidence to share mistakes with others, including the supercilious egomaniacs of the world who feel compelled to tell you how much better they would have handled this. I do hope their insensitive remarks don't offend you. Your videos are as educational as they are entertaining, and I thank you for sharing!
Is there a reball try video? I could not find it and this is a year old video.
Not sure if it works on the consumer models, but on the pro version on the LG screens you can enter the service menu with a regular remote.
Press and hold menu until the menu disappears, then press 0 (zero) 4 times and the set or OK button.
And if you have a samsung screen you turn it off, press mute 182 and power on, and the service menu should appear.
Be vary careful in the samsung service menu, you can actually brick the screen.
did you try to heat it /cool it while it was powered on?
Shades of a repair I have done a couple of times on old PS3 following the “Gilksy guide”.
22:08 "so you gotta be looking carefully for it... so hopefully those joints get hot enough"
good one! got me to stop what I was doing and look at the screen.
Now we definitively want to see you repair this TV ! Is like a personal challenge for you .:)
Remove, clean the board with a solder wick, try wiping a thin layer of solder paste on the chip ( while it is upside down and alone ) to attempt to have it reball with out a stencil
If it aint broke, fix it until it is!
I like how Dave only decides to do the right thing after he does it the wrong way. :P You needed the very liquidy flux to slide under the BGA from the start. And NOT TOUCH IT. And good use of Kapton tape at the end.
Hi Dave. First thing, you should be using proper flux for reflow. Take Louis Rossmann's offer below (he knows well).
Second advice, warm the board to about 160-180C on pre-heater. It is most likely lead free solder there so you need to run it hot. When you get the solder flowing with the hot air gun, don't use maximum flow, it may blow some small components around it off. Third advice, never push down on the chip, instead, very carefully push the side to check if the solder is flowing. In this case I doubt the reflow could have fixed the issue. I'd suggest chip replacement or entire board, which you can buy used off eBay. Thanks for your videos, enjoyable! Best wishes!
Cracked joints can usually by identified by applying pressure to the top of the BGA while its running. Look for the picture changing. Failing that try heating and cooling the BGAs one at a time while it's running. The expansion and contraction will often show intermittent faults, but also temporarily fix o/c joints by breaking through the oxide. The PCB vias under hot BGAs can often fail due to expansion and contraction, it's not always the solder joints. The DDR RAM chips can fail. We often have issues with them not going down properly in the first place because they're so light. We find the larger metal topped BGAs usually go down okay, but suffer more expansion contraction fractures longer term, so I always suspect the hotter running chips.
@27:00 Mac access? Call Louis Rossman....Wheres the flux
I am confused by the concept of reflowing... Can someone tell me why it is "safe" to heat up chips to 400+ degrees, when cpus like intel chips have a tjmax of 100 or thereabouts degrees (start to break when they go over this) ???
Cause he's heating them when the power is off
Lets say this fault could be fixed by a successful reflow, would applying a force to the chips in turn help diagnose which is the culprit. I am assuming that it was once working and if it is a failed solder ball then it must only be a hairline fault and a small force would temporarily re-make the connection.
You can poke BGA chips. You also need to poke them when reflowing to make sure all the balls melted. What you should not do is apply pressure. Poke them from the side, with tweezers, and apply just a little tiny bit of force, just enough to make it move a bit.
Nicely done Mate. Thumbs up! You gave it a go. More than I woulda. Id a just changed the board.
Chris Gammell of contextual electronics, I think he's on a pretty famous podcast...
dug a 55" Philips 4K out of the countys land fill on 1 of many TV rescues I do, the kicker was whoever chucked it actually taped the remote to he stands base as well... *BONUS* baby!!!.
The problem was ez-pz to rectify, just had to replace the LED backlights,.... all 52 of them. w00t!!
I would love to see you try to go down the rabbit hole.... Continue to try to fix it
stupid BGA's! Reball the sucker!
Thanks for the video as always! It feels nice to see I'm not the only one bodging up repairs like this. Can't win 'em all!
What a complex circuit! Here I thought displaying a picture and playing some sound was a simple thing
my first thought was the MPEG decoder is screwed...but it could possably be the RAM on either the main decoder chip or the U14 or URSA9 chips...looks like a PC graphics card with bad RAM...one of the RAM chips on URSA9 looks to have something on the top (notice you can read the other 3 fine)..the glue blobs maybe there to help keep the chips from lifting under heat stress..
but meh! its dead now!...send it to Louis to have it reballed..he seems to enjoy that crap!
That was my initial thought, one of the ddr3 modules (bga's) is likely toast. Perhaps the pair on the left in the illustration is the framebuffer memory. (the one marked with 16x2 lanes?) That said it could still be a power issue, the chip will consume more power the moment you play video and a PSU rail might be dropping.
"looks like a PC graphics card with bad RAM" was my 1st thought when i saw the 1st video.
Yeah, my bet is on the RAM... It is not even Samsung!
Adding to this the OSD would just be superimposed on the data before going to the LCD panel, so the chip you desoldered likely had little to do with the issue unless there was a problem with the input side of said chip.... you can see that the video selection and OSD is pristine so it would have been the main SoC that was decoding the video where the issue lied, and it didn't look to be the chip you ruined. Also you failed to do the tap test, tap, press, super cool via compressed air trick, bend various areas around the chips and see if symptoms differ... etc.
2/3 of this video is you showing us LG copyrighted manuals without authorization. Doesn't this constitute copyright infringement ?
No Dave! It could be the ram unit I mentioned earlier.
Also, kapton can create 'ovens' where heat gets trapped and melts connectors instead of protecting them. Kapton can also move on you and pull all those nice parts off their pads.
At least we know the MAC Address for the tomb stone ;-)
my guess would have been something to do with hardware compositing which seems fairly correct given what you found
19:08 that board looks like toast where the cip was on the other side. Something got way to hot
Dave would make a great video to see you trying to re-ball that chip. I think a lot of people would like to see too. These try to fix it videos are excellent.
NO flux? Blasphemy!
Edit: bumped it a bit too much, time for reballing
Dave: you, like all of us other techs, are the victim of the industry using Eco Solder. When they started using it, the temp that causes it to melt was lowered and now we have failures due to it. I try to use old lead based solder when I can as it has a higher temp to it. Keep up the good work my friend!
Great video as always Mr Gammell
I'm so much better than that Aussie dickhead!
@@EEVblog That's what you get for using Bing as your search engine, mate :D
9:00 32KBI$, 32KBD$, 1MB L2 $. That's creative. What I think happened is that because cash and cache are pronounced the same (at least in non-Aussie English) someone symbolized cache with a dollar sign.
@@Okurka. Interesting. Do you have a reference that using a dollar sign to denote cache is a common thing?
I replaced a defective mainboard in one of these about 1.5 years ago, it was displaying a cycle of red/green/blue/white/black constantly and wouldn't respond. Board cost around $220 and I sold the TV for $1400, not bad.
99% it was a ram failure, not that chip.. but now who knows? Throw the board in the bin and buy a good used one, problem solved.
Same thing happened to me at one point,replaced the board and where the chip is,I placed a fan and heatsink on it and now it runs cool-ish
I wrote a script at work that uses the RS-232 on an LG TV to automate entering text on the keyboard. Also, on some models you can change Debug Status to "EVENT" (in the Instart menu) and it'll unlock all kinds of cool debugging menus if you type the word "debug" on the RS-232 terminal.
By the way, you should be able to simulate pressing the Instart button to open the service menu by sending "mc 01 fb" over the serial port. The password is 0413.
excellent video, by the way. i love seeing your rationale and troubleshooting process. engineering is all about problem solving after all
In the manual and at 7:16 in the video - I noticed 'gradiation' (right side) seems to match your fault.
First of all - why should the chip move when you just heat it up? It was already completely centered when it had been reflow-soldered at the factory, so it will not jump around that much you can see. And 2nd suggestion: Never ever try to reflow completely without flux, because even if it will heat up properly the soldering connections will just get briddle and oxidized when heating up them again. No flowing activity will really happen without flux. Do like Louis (Rossmann) would do, flood it with flux gel and you will be fine... ;)
If you put a little flux around what you are trying to re-flow you can tell the chip has reseated because it dances. That's the point at which you stop heating. Also flux around the chip insures you don't have dry balls. Nobody likes dry balls during a re-flow.
This should be called "Why there are so few TV repair shops left."
@19:08 it looks brown under where the URSA chip sits
can you send the board to someone to reball? it's a nice TV, I think is worth. Please more troubleshoot-reverse engineering- repair videos, thanks!
Shipping cost would be too much to be worth it, unless it's a local place.
There is maybe somebody repairing phone pcbs anywhere near. They could reball it.
Always good to see things not going to plan
I think that everyone is terrified by reballing stuff - but it seems like everyone that tries it gets success eventually. Maybe do an interview with a person that reballs stuff, then carry out their suggestions for an episode. Getting it to work will be really satisfying, there's a lot of gamers that want to know about this for the Xbox red light of death etc, a lot of those consoles had solder problems.
I say go for it.
Pink screen remembers me old tv tuner card, program was drawing a pink area and tv tuner card overlaying image on that area. In my opinion Dave found problem on diagrams correctly.
a possible fix for it would be to take it off, reball with leaded solder, and then use that to finalise alignment
as, if they used lead free, you'll never get it aligned by hand
Probaly find it is one failed resistor or capasitor next to the chip.
Glad to see you gave it a shot.
I know this is a crazy though, but could it be something as simple as a mis-match between the frame rate being sent and frame rate capable of the monitor?
1) I'd check for a cross-over between the speed control crystal on the 3d vs 2d sections of the board.
2) I'd check to see if the crystal isn't soldered correctly / missing entirely on the GPU video output line.
I can't wait for you to hit a million subs. You need a play button in your office!!!
Trobble is it is the internal bonds to the die that oftern fail. In which case heat will only temporaily revive it.
I had an LG TV that had a big black line down the middle of the screen so I found a crack in a resistor in the middle of a ribbon cable and re-soldered it and it worked find for a while then I got another line and fixed it then got another line , problem was it had about 10,000 screws to take it apart, what a freakin nightmare, the labor costs makes repair impractical even if you know what the problem is.
did you check the internal connectors , I remember someone going through a lengthy diagnosis only to find bent pins on a connector... just as I say this he addresses the connectors.
i think better than re-balling the chip,try searching aliexpress or ebay for a complete replacement board (used or refurbished one) will be cheap enough i think
I've been there too and learned the leason. Once you poked that chip I remembered myself doing this on a friend's laptop (bought him a new laptop from my pocket).
15:57 Maybe you can try to use a USB keyboard with the TV and try keyboard shortcuts from the PC or search the web for service mode with the model number. I bet those TVs have other ways to go into a diagnostics mode or run a diagnostics app. Maybe they call it maintenance mode.
That SysRQ message means it acts upon sysrq keys, so if you find a way to send it sysreq-h (for help) you might be able to see if it reacts on anything at all
That dodgy looking RAM IC is probably the cause, you overlooked it - there's always a framebuffer for these chips and it's stored in the RAM. There are 4 RAM blocks there and 1 looks entirely different, so I'm betting that was what was causing the problem...
with reballing, I dont think lead free solder has the surface tension to pull BGA chips into alignment
I'm pretty sure you need an xray to check alignment, there
dunno which they used though since I'm not into consumer product standards and rules so idk if they have to use lead free
My immediate assumption would be the MPEG decoder went wonky. Let's watch the rest and see what happens.