What "loose components" on the motherboard cause bootloop, LG warranty repair procedure?

[Tysrsx1]

I managed to shatter the screen on my beloved LG G4 by sitting on it! I have replaced the bezel/screen/digitizer on my G4 (purchased June last year) with a OEM replacement. Right after replacement phone worked fine but the proximity sensor was not operating correctly because I had not installed the small rubber bushing that it sits in. Shortly after phone went into boot loop. After replacing the bushing and a hard reset, I am still having the boot loop issue. I assume that I have caused the now known "loose connection" issue to manifest by disassembling the phone to replace the screen despite taking great care in both disassembly and re-assembly. Everything worked perfect before disassembly, and everything worked fine after full assembly aside from the boot loop. I am convinced that this is not that big of a fix as I did not in any way force any of the components while changing the screen.

I need the seasoned minds on the forum (who never seem to let me down) to tell me what "loose component connections" get serviced when LG does the warranty work. Any advice on the method that LG uses to correct the issue would also be greatly appreciated. (Dont bother with the youtube links of oven baking and the like, Ive been there already, looking for a legit repair and preferably someone with experience inside of the phone)

Thanks in advance for any help. And sorry if my search did not turn up an already developed thread on this issue. I am now demoted to using my well worn gen 1 Moto-X until I resolve this issue or the Note 6/7 releases. Please help I need my big screen and OIS camera back ASAP!!!!!

 

[ManiacJoe]

Re: What "loose components" on the motherboard cause bootloop, LG warranty repair procedure?

All the reports I have read say that the boot loop problem is caused by bad soldering on the mother board. Assuming that is true, there is no fix possible by the user as the mobo needs to be replaced.

 

[tardus]

Re: What "loose components" on the motherboard cause bootloop, LG warranty repair procedure?

All the reports I have read say that the boot loop problem is caused by bad soldering on the mother board. Assuming that is true, there is no fix possible by the user as the mobo needs to be replaced.

I've asked this before, never got an answer. Why does LG at times list the repair solution for bootloop as "replace flash memory"?

 

[Tysrsx1]

Re: What "loose components" on the motherboard cause bootloop, LG warranty repair procedure?

I would think that if the bad solder joint could be pinpointed specifically that one may get lucky by reheating the joint with a needle-point iron. I have had similar isuses on other devices and managed to get them straightened out. Isolating the bad connection is a must tho. I cant understand why there is no information out there on this being that it is a recognized issue.

 

[Tysrsx1]

Re: What "loose components" on the motherboard cause bootloop, LG warranty repair procedure?

Are there any LG affiliated people on the forum, possibly someone who does repairs?

 

[tardus]

Re: What "loose components" on the motherboard cause bootloop, LG warranty repair procedure?

Are there any LG affiliated people on the forum, possibly someone who does repairs?

If there are, only lurkers. I've never seen a person claiming to work for LG commenting on this subject.

 

[Tysrsx1]

Re: What "loose components" on the motherboard cause bootloop, LG warranty repair procedure?

It is just so strange that even though we know there is an issue, that it has not been specified.

 

[zan_toka]

Re: What "loose components" on the motherboard cause bootloop, LG warranty repair procedure?

This person on YouTube seemed to remove the processor from the motherboard and reheat all the solder:
https://www.youtube.com/watch?v=F02SgZN4L1Y

This person simply heated some kind of gel on top of the processor, could it be that simple to fix??:
https://www.youtube.com/watch?v=cadWAgYcmGc

I'm about to send mine to LG...hope they fix it.

 

[RandyOhio]

Re: What "loose components" on the motherboard cause bootloop, LG warranty repair procedure?

My uneducated eye tells me after looking at a few of these videos that they are putting Flux on the two larger chips, heating then, causing the Flux to flow, heating all the connections, causing the solder to flow and seal the cracks, then cleaning everything with alcohol.

Posted via the Android Central App

 

[Im Broken]

Re: What "loose components" on the motherboard cause bootloop, LG warranty repair procedure?

Same as the old Xbox RROD. Also some Lenovo laptop GPUs. It's just a solder reflow if that's really the problem.

 

[talonsmith]

Re: What "loose components" on the motherboard cause bootloop, LG warranty repair procedure?

I've done this with old HP laptops too with heat guns on the GPU. The solder would pull away from motherboard circuits and cease working.

 

[Mooncatt]

Re: What "loose components" on the motherboard cause bootloop, LG warranty repair procedure?

I've done that on an Nvidia laptop GPU, but it only worked for a short time. Repeated heatings resulted in shorter run times, until eventually it wouldn't work at all.

 

[zan_toka]

Re: What "loose components" on the motherboard cause bootloop, LG warranty repair procedure?

After sending my phone in to LG 2 weeks ago (via FedEx Ground which took about 1 week to deliver,) they called me today and said the repair will cost $146! I said I'd think about it, but I have to respond by today. Ugh. I wonder if that repair will include not only the boot loop/motherboard but also my cracked screen...that would be great.

 

[cold spring]

Re: What "loose components" on the motherboard cause bootloop, LG warranty repair procedure?

Yes those two videos show exactly what is the cause of boot loop issue with LG G4. LG G4 has ram layered above the SD 808 SOC. So when SD 808 generate lot of heat and expand, solder bond to ram above will likely crack. Somehow, the low temp solder LG used in it's BGA chips is prone to this failure. Obviously it's not the ram chip itself or SD808 chip, as they have proven to be reliable on other brand phones. So the solution seems to be to remove the chip and replace solder with normal leaded type solder. So first video shows exactly this - a very skilled person taking off the ram and carefully cleaning, refluxing the connections with normal solder and re-attaching the ram above the SOC by HAND!! That is pretty damn incredible job. Second video is similar, but the person didn't bother to take off the ram, and just applied some flux and heated the ram chip which hopefully will resolve the issue. But probably second approach is only a temp fix, since defective solder is still in place. Sooner or later, it will fail again and go into another bootloop. I guess the videos are encouraging in that it doesn't take a million dollars of hi-tech equipment to fix the LG G4 bootloop issue, just extremely skillful and steady hand for resoldering job to replace the defective solder on the ram chip.

 

[electricrelish]

Re: What "loose components" on the motherboard cause bootloop, LG warranty repair procedure?

Can you advise me on what I need to do to request for my LG G4 to be repaired? I just got the bootloop issue on my phone manufactured in December 2015; so I don't think there is any manufacturer date that is safe from this issue.

Also do they warranty their work for any specified? time?

 

[muckrakerX]

Re: What "loose components" on the motherboard cause bootloop, LG warranty repair procedure?

Can you advise me on what I need to do to request for my LG G4 to be repaired? I just got the bootloop issue on my phone manufactured in December 2015; so I don't think there is any manufacturer date that is safe from this issue.

Also do they warranty their work for any specified? time?

Check your other thread, the last post has a link to LG support,

 

[Adam Frix]

Re: What "loose components" on the motherboard cause bootloop, LG warranty repair procedure?

I managed to shatter the screen on my beloved LG G4 by sitting on it! I have replaced the bezel/screen/digitizer on my G4 (purchased June last year) with a OEM replacement. Right after replacement phone worked fine but the proximity sensor was not operating correctly because I had not installed the small rubber bushing that it sits in. Shortly after phone went into boot loop. After replacing the bushing and a hard reset, I am still having the boot loop issue. I assume that I have caused the now known "loose connection" issue to manifest by disassembling the phone to replace the screen despite taking great care in both disassembly and re-assembly. Everything worked perfect before disassembly, and everything worked fine after full assembly aside from the boot loop. I am convinced that this is not that big of a fix as I did not in any way force any of the components while changing the screen.

I need the seasoned minds on the forum (who never seem to let me down) to tell me what "loose component connections" get serviced when LG does the warranty work. Any advice on the method that LG uses to correct the issue would also be greatly appreciated. (Dont bother with the youtube links of oven baking and the like, Ive been there already, looking for a legit repair and preferably someone with experience inside of the phone)

Thanks in advance for any help. And sorry if my search did not turn up an already developed thread on this issue. I am now demoted to using my well worn gen 1 Moto-X until I resolve this issue or the Note 6/7 releases. Please help I need my big screen and OIS camera back ASAP!!!!!

http://forums.androidcentral.com/lg-v10/754434-boot-loop-problem-my-factory-repair-story.html

 

[8succi8]

Re: What "loose components" on the motherboard cause bootloop, LG warranty repair procedure?

I sent mine to LG, took one business day I might add. That was on December 29th they received it. I heard NOTHING from the repair company OR Lg on the matter until I had a chat with a rep in January. That rep assured me the repair company had been contacted and they were awaiting a reply..no reply came. In February of this year I had another chat with yet another Lg rep and that person assured me of the same thing..so I emailed the repair company myself since the number listed online for them was NEVER answered...they beat around the bush for 8 emails and nothing...so last resort I put a "nasty" message on LG's Facebook page and got a response within a day..I messaged that account and within a few hours I got an answer! So two months later I find out that the repair has been put on hold because there was apparently some water damage and they weren't touching it because of that unless I agreed to pay 149.99 plus taxes to fix it. I waited that long to hear that my phone had not been touched..was sitting collecting dust because nobody could open an email to send me a message. I told them to send my phone back. They sent it back to me on February 21st and I received it today, the 22nd and that's only because I messaged that Facebook account again and asked for a tracking number. I am going to replace the mobo myself and sell it.

 

[Sheng Liwei]

Re: What "loose components" on the motherboard cause bootloop, LG warranty repair procedure?

I wish what you said was true. But I think it was not the case. I think the flash memory/ram was utterly destroyed by the CPU underneath over time. There is an electromigration effect, which is the current causing the atoms in the wire to move, this is especially pronounced when the current density is high(in thin wires of IC) and temperature is high. The effect is accumulative, over time the current carrying wire could be broken by the current like a fuse. Somehow the broken wire can be affected by temperature like extreme heat or cold, and appear to be reconnected, but it is only temporary, and getting worse after each temporary fix. The real fix is to replace the affected part, because the damage can not be undone. Like shown in 1st video, the chip was replaced and was not put back. This is a design flaw in LG G4, the heat dissipation is not very effective, and the memory chip is not rated to work under high temperature for very long. I would suggest to put real copper shim on top of the memory chip to help lower the temperature at expense of a higher LCD temperature, maybe this can delay the bootloop from happening(more than 5 years would be nice), or a better designed flash memory chip(rated at high temperature) can also be effective.

Yes those two videos show exactly what is the cause of boot loop issue with LG G4. LG G4 has ram layered above the SD 808 SOC. So when SD 808 generate lot of heat and expand, solder bond to ram above will likely crack. Somehow, the low temp solder LG used in it's BGA chips is prone to this failure. Obviously it's not the ram chip itself or SD808 chip, as they have proven to be reliable on other brand phones. So the solution seems to be to remove the chip and replace solder with normal leaded type solder. So first video shows exactly this - a very skilled person taking off the ram and carefully cleaning, refluxing the connections with normal solder and re-attaching the ram above the SOC by HAND!! That is pretty damn incredible job. Second video is similar, but the person didn't bother to take off the ram, and just applied some flux and heated the ram chip which hopefully will resolve the issue. But probably second approach is only a temp fix, since defective solder is still in place. Sooner or later, it will fail again and go into another bootloop. I guess the videos are encouraging in that it doesn't take a million dollars of hi-tech equipment to fix the LG G4 bootloop issue, just extremely skillful and steady hand for resoldering job to replace the defective solder on the ram chip.

 

[cold spring]

Re: What "loose components" on the motherboard cause bootloop, LG warranty repair procedure?

Yes using copper shim to dissipate heat is very good suggestion. I have made same recommendations in other posts about LG G4. But couple of points - 1) professionals in logic board repair will tell you there is easy way to tell if a chip is truly damaged or it's simply not working due to solder defect - which is apply some pressure and find out! 2) I obtained several LG G4 in bootloop state, and checked myself, and indeed, most of these can be revivied by simple application of pressure. So I believe the core issue is defective solder used by LG. Of course there could be other issues causing bootloop, such as defective qualcomm power chip, or even defective discrete components like capacitors, but predominant cause of failure is probably defective solder - at least this is my finding from looking at multiple bootlooped LG G4. Sure electromigration can cause chip failures, but I doubt that this is responsible for such rapid failures we see in LG G4. Most likely accelerated electromigration failure will be fairly gradual showing up as reduced life of the device but you don't expect to see such short term, abrupt increase in large scale failure as in LG G4. Laboratory testing for electromigration at elevated temperatures (125 deg C) show that devices can have shortend life for 2 or more years, but this is far less aggressive failure mode than what we see in LG G4.