yashsingh1/xdaforums huggingface dataset:
[HD2 General] ubejd:
i reaheated again ... im able to boot wp7 without a problem...:D ... but volume keys and keypad buttons still doesnt work... do you have a schematic to make those connection just if i can fix red - power on button and back button... because im unable to make tests on it ... if i open a program im unable to return back... or when phone goes in sleep mode im unable to wake up - unles i remove battery and turn on again...:cool:

thanks for your support :D
[HD2 General] motoi_bogdan:
well, it's some kind of small success :p

try to heat the phone with some external source (hair dryer for example) to see if you can induce some freezes or restarts while continuously rebooting the phone . Loading an OS is also pretty resource intensive, it could help at some small level.

For the moment don't attempt another reheat until you determine if you got any improvements relating thermal stability. One tip would be to heat the phone using a hair dryer while it's turned off and when it's kind of hot, attempt to start it to see if it freezes or gives you that 7 vibrate pattern.

Now about the button problems. The volume buttons for example, use 3 pins (wires), one being common for both up and down contracts. When you press "up" for example the common wire will make contact with the up wire. This is similar for the "down" button. If you examine the small pcb on witch these buttons are soldered (connected to the flex cable) you will see 2 letters (A and B) near each button. The A pin of each button correspond to an individual wire, the B pins are common and corespond to one wire. So, 3 wires will come out from this PCB to the flex cable. If you got a multimeter, place it on continuous voltage measurement and measure the voltage across one A pin (one of the buttons) and one B pin. A healthy motherboard will give you about 1.4-1.5 volts there. If the command circuitry has failed, you will get about 2.3-2.8 volts. You need to determine that first.

I'll post some pictures about how i solved the problem, you may look on them to see how i attached some wires there and did some measurements.

About the red/green/home/etc buttons. Like i've said, the last HD2 i've repaired also has this problem. I'll be looking into tonight, i also must find a fix for that one ;) (i need the menu and back keys in android).

to draw a line there, these problems (volume keys, front keys failure) occured on this HD2 in a "natural" fashion. The device suffered from bga soldering failure. In this particular case the buttons failed along with the more familiar cpu freezing and vibrate patterns. This clearly indicates that the snapdragon "system on a chip" contains all the I/O controllers inside it's casing. The buttons are directly linked with this chip. That's kind of a new discovery we made simultaneous, you and i, but it's also kind of bad news. The crappy bga soldering can also affect buttons, display, touchscreen operation etc. It is possible for someone to not have freezes or restarts but to have a failed touchscreen or buttons due to this problem.

I will come back with more results and some pictures. ;)
[HD2 General] ubejd:
I gues yes :D

i will wait for those pic. ... thanks again for your support....

anyway im waiting to hear from my friend about removing cpu and soldering again... i send it cpu back pic - which you provided and thanks for that too... about volume keys i will try do do some thing and report again.

a question... does paste help while heating cpu ?
[HD2 General] ubejd:
ThANK you a million time my bro ( if i could i will donate to you ... i work for a 150 euro for a month).

Report : i booted my phone in wp7 uploaded a video 480p and let it play but after 15 min it restart ... still overheating problem.

i will try this tomorrow and course report back... i will take your advice for cpu problem... i will rehoot tomorrow ate 300 - 330 degrees and make some test.. if at some point doesnt work i will make my last move to resolder cpu.

have a nice night my bro... and thanks again
[HD2 General] DJ_MiX:
sorry to go off topic, but do you know where I can get those tiny little smt buttons to replace on my flex cable for volume up down?

and back on topic you guys should work on a reflow profile for the cpu simliar to xbox reflows to fix rrod.

I have a reflow station and use a termocouple for criticial reflows like this sitiuation.

if you master a good reflow profile you might get better results to not damaging the cpu.

but reflowing the cpu is not a premanent fix, it might work for 3 months ok, but then heating and freezes may occur again. keep us updated on the results
[HD2 General] motoi_bogdan:
:p i also work for some 150 euros a month, i know how it's like, no worries, crappy romanian salaries.

I recommend a maximum temperature of 340-360 degrees for this chip, no more. Otherwise you risk .. kind of over melting the bga matrix and that could result in some balls making short circuits with each other.

@DJ_MiX uhh.. i don't think it's likely to find those smt buttons at electronics stores. Best chance - other phones or similar devices. In the past years i collected a good deal of broken pda's, pna's and broken phones exactly for this purpose.

reflowing a chip can last anywhere from 1 day to eternity. It depends on the success of the reflow and the chip's soldering. It's common on gpu's or larger and powerful chips (pc motherboard northbridges for example) to fail some time after the reflow operation. Some service center give you some 2-3 months as an estimate. However reflowing has greater success on smaller chips or least powerfull ones - the ones with smaller power/thermal dissipation or lower thermal designs. HD2's chip, is an example. It does produce heat, but nowhere near it's desktop counterparts or larger thermal design chips.

xbox and rrod problem is one case of large chip and high thermal design that can't be effectively repaired only by reflowing.
[HD2 General] DJ_MiX:
facdemol Thanks, I sacificed the buttons off the flex cable on the keypad.

just wish I could find them new from supplier
[HD2 General] ubejd:
at last we made it

Well i have a great news...:D yes i do .... after heating to a 340 - 360 degrees it works... im making some tests until now no restarts... no fatal hit etc... phone get little hot but it keeps working without a problem... for the moment im in windows phone 7... ( im unable to make some other test because my buttons dont work - it seems they are little damaged ) im playing a video 3 times until now video length is 80 min at 480p usually it will restart after 8-10 min and it will be impossible to start again unless you put it in a fridge to cool down.

So i think for now thats only solution to fix it or brick it all!!!

about reflowing a chip depends what chip... usually phones chips have success.

So i think facdemol you could update your first post for definitive solution

i took some pic...:D
[HD2 General] lukesan:
Wow, that looks absolutely cool!

Congratz on this one.

Did you put a bit of weight by any means on the chip or does it go 'down' because of gravity?

These BGA chips, well I don't like them one bit. They have been on the market quiet a long time and are always causing issues which are very difficult to fix and you don't have any control over it.
[HD2 General] ubejd:
Thanks

No, no weight just heating, it goes down without touching and i believe that touching could be very risky, heating at that degree will melt bga matrix and that could result in some balls making short circuits with each other.

Me too... i dont know why they just dont move - invent to something more secure!!!
[HD2 General] motoi_bogdan:
@ubejd good news indeed. :p I'll await to see if i can find another hd2 to check a few things these days and i'll update first post.

I'm thinking if it's possible to heat the board in a gas/electric oven, tried already with one of the hd2 but my crappy oven couldn't raise the temperature above 190 degrees. If that will be possible, normal people (the ones that don't have smd rework stations or the room in witch they sleep, full of service equipment :p) could also get a practical chance on solving their problems.

Keep trying on that damn button connector. It gaved me some headaches when i fixed my last hd2, even now although all buttons seem to work, the red one must be hard pressed to do it's job, don't know why. I cleaned the flex cable with some isopropylic alcohol and the motherboard in a ultrasonic cleaner device. Still once you connect/disconnect that flex cable couple of time, it gets harder to make it work again. That's if we assume it's corresponding pins under the cpu weren't damaged in the reheat.

However, even so, i would not risk another reheat if i got the phone to not make any restarts of freezes. At least i could use it as some PDA or flash it with CM7 nandroid and remap the hardware buttons or install some onscreen buttons.

Well done in getting the phone thus far (and not killing it :D) !

@lukesan i also hate bga chips, if it weren't for them i would not have bought a smd rework station and instead i would got me some beer. But, smd is the future and as long as phones keep getting smaller/thinner it would call for more smd soldering fun to get each problem fixed. Bleah...
[HD2 General] lukesan:
-Drill holes in the pcb and attach a wire to each contact :-)

-a pure i2c with only 4 connections or just 1 ic without a pcb

Now the question is, why does this one become detached?

Is it because of mechanical stress or pure temperature and can we do anything to prevent it.
[HD2 General] ubejd:
@ facdemol

Thank you me friend for your support.

If i can help write me... i will do my best :D.

Did you cover with something mainboard or you just put it... because it could do harm to microphone, sim card holder and some other plastic, i know you now all of that :D ,but i thought to mention if someone wanna try.

About keypad flex i will have to wait until monday and i will try to make some tests... for volume keys too, of course if i succeed i will post some "how to" pic.

if everything goes good there is no way im gonna try again to reheat ... definitely is keypad flex problem because opened to many times my hd2 and thats the problem.

@ lukesan

im not a professional but i think often it happens while we keep flashing to many times or phone dropped...etc.

In my case when i bought it was like new one but it was i bad condition in software system look the pic... i fix it with jtag method and than tried to flash room bad it got hot so i started to read and learned ( we still have to learn) what was caused this.... and ended up here -im glad for that:D ( a big thank you goes for community here and of course for Facdemol for sharing with us).
[HD2 General] motoi_bogdan:
About the "oven theory" :p

Industrial pcb making and assembly involves a lot of heat as the whole pcb (with all components) are placed in industrial ovens and "baked" for about 15 minutes. By manufacturing standards, all components on a pcb must be able to handle the heat of such processes.

In the case of the hd2 motherboard, only the rubber cap over the microphone is sensible to heat. If that is removed, the whole motherboard can be placed in an oven, without a risk. I tested this on my dead hd2 motherboard, there was no damage to the plastic components/connectors. Even if it may seem improbable, they can withstand the heat, at least around 200 degrees. If i get another mainboard, i'll surely try the oven approach. I belive it to be an alternative for regular hd2 users.
[HD2 General] metroidnemesis13:
What is the fatal hit specific error code you're getting facdemol? You think that's my problem?

http://xdaforums.com/showthread.php?t=1019039
[HD2 General] Ev0luti0n_:
this would be very cool facdemol! it would enable a lot of users to have a safe method in the future to repair their beloved phones :) as to me i can only thank all of those who are trying, since i love the HD2, and don't want to switch in the near future due to a problem like this!

the last time i was in love with a phone, i had it for 4 years! it was a siemens sx1... hope my hd2 lasts for this long! :D
[HD2 General] motoi_bogdan:
@metroidnemesis13 : i don't remember it exactly, they all seem to be "fatal", be it magldr, winmobile or otherwise. However, i remember receiving your error some time ago, with one faulty hd2. It was running nand android, got hot during some testing and attempted to restart by it's own. Once in magldr, android could not boot up and a fatal error was shown. If the phone was placed in a freezer for some 20-30min, then restarted, it would boot normally. So, in this case the problem is thermal related (same story.. the bga balls, the cpu, soldering etc). This is one possible cause. However a corrupted nand memory can also produce the same symptoms. If you manage to relate your original problem to heat, then the phone will need to have it's cpu reheated. If not, you may have a corrupted nand memory.

@Ev0luti0n will try cooking in the oven. However at this time i don't have any more hd2's. The ones i repaired in the past are working fine, i can't test this on them. I'll see if i can get another faulty hd2. I have various parts to assemble a eu hd2, but in need of a motherboard with this fault. My working hd2's are all tmous.
[HD2 General] DTNT:
Would be great by your side if you do experiments with the oven. And can it be done by hair dryer or by leaving motherboard on the dashboard of the car for a long period?! And can you explain simply what does reheating do with the chip? is it remelts and resolders pins of processor?! right?! If so, is there are chance to melt again with hard loaded processor? Thanks
[HD2 General] booze_pistol:
facdemol wanted to first say thanks for all your work. I have searched everywhere for an answer to this exact problem. i have 2 tmous HD2's that suffer this overheating issue. even if I can never get them to work again it is good to finally know the answer.

I am willing to try this in the oven if you would pass along what you think the settings would be, as far as temp and time? I'm sure you have some idea of how you would try it if you had one to experiment with. I got basically nothing to lose, my phones are paper weights for now.

Lastly would same fix be possible with a heat gun, and a thermal thermometer to monitor the temp? Not as perfect as hot air station, but seems with the thermometer you could regulate the distance from the heat gun, and regulate the temp reasonably. Just wondered your thoughts on this?

Again many thanks for your work, it is good to know that maybe, just maybe my phones can be fixed.
[HD2 General] lukesan:
Both things you mentioned are not hot enough to melt solder.
[HD2 General] lukesan:
Ok only things to gain it seems by doing this.

I just checked the solder wiki

----

Much recent research has focused on selection of 4th element additions to Sn-Ag-Cu to provide compatibility for the reduced cooling rate of solder sphere reflow for assembly of ball grid arrays, e.g., Sn-3.5Ag-0.74Cu-0.21Zn (melting range of 217–220 ˚C) and Sn-3.5Ag-0.85Cu-0.10Mn (melting range of 211–215 ˚C).

----

So approx 428 Fahrenheit would be the meltingpoint for our 'modern' ROHS compliant devices. Since that is the meltingpoint I would add 5 to 10% to that temp to make sure it flows.

A couple of things to concider:

- only the pcb, no cables etc. So no quick trying because that will end in a big fail

- hot air gun. Cover the rest with aluminum foil so you will not blow smd resistors etc from the pcb. Also concider the fact that you have to blow vertically because of the reason that the chip is not concidered to move sideways. Start measuring the temperature with a infrared thermometer. Start from a distance and move towards the chip slowly to get to the desired temp.

The standard kitchen oven is another thing.

Is the temperature that you have set correct would be my main q.

I would put something in the oven before you try the HD pcb and measure the temperature of the object after 5 minutes (depending on the mass).
[HD2 General] motoi_bogdan:
first of all, you don't want to really melt the solder points. ;) should this happen, the sphere like balls in the bga matrix will collapse to the bottom, flatten themselves and touch eachother. What we want is to ...well... semi-melt the solder points.

Although most solder alloys will melt below 250 degrees celsius, simply applying this temperature above the chip, doesn't mean that the heat transfer will be perfect and thus the temperature at the bga level will also be 250 degrees. The board itself also dissipates heat. This is why when desoldering with smd rework stations we use temperatures above 300 degrees.

I don't think a heat gun would be enough, and also it's dangerous because you can't regulate/change the air flow speed, thus risking to simply blow away smaller components near the chip itself.

The oven provides a fairly uniform temperature, it can be regulated and measured and produces a smaller thermal stress to the components by allowing the whole motherboard to expand due to dilatation at the same rate. Standard gas ovens can heat themselves up to around 280 degrees, this is also valid for most electric ones.

At this time, please don't try this yet. I'll be performing some tests using some thermal probes and a hd2 motherboard with the cpu removed, in order to directly see the effects of heat on the soldering itself. I'll then reposition the cpu and measure the temperature dropout at the board level, underneath the cpu, to determine if this is enough to effectively semi-melt the solder points.

The plastic parts of the motherboard are heat resistant EXCEPT the small black rubber cap over the microphone, this must be removed prior to heating.

I'll update the thread once i have the results.
[HD2 General] booze_pistol:
Thanks for the thoughts. With regard to the heat gun I had definitely intended to shield the other components . It's probably a long shot method but if it could be done successfully, detailed as far as temps, times, etc. and repeated, would also be a solution more readily available to those without a professional setup.

If the oven method proves to be a viable solution and facdemol gets the temps and times, it would be advisable to use the infrared thermometer to check the actual temps, because all ovens would certainly vary +/- ? degrees.

It would definitely be nice to find a working solution with a reasonably high success rate. We loved these phones, and hope to get to use them again soon.

I am used to having to do things in a "non conventional" way. I just replaced a TSOP chip on my laptop motherboard using a a Weller/Portasol P1 Butane Soldering iron, with a regular soldering tip. Let's say tedious and stressful, but ultimately successful.
[HD2 General] booze_pistol:
I don't think a heat gun would be enough, and also it's dangerous because you can't regulate/change the air flow speed, thus risking to simply blow away smaller components near the chip itself.

The oven provides a fairly uniform temperature, it can be regulated and measured and produces a smaller thermal stress to the components by allowing the whole motherboard to expand due to dilatation at the same rate. Standard gas ovens can heat themselves up to around 280 degrees, this is also valid for most electric ones.

At this time, please don't try this yet. I'll be performing some tests using some thermal probes and a hd2 motherboard with the cpu removed, in order to directly see the effects of heat on the soldering itself. I'll then reposition the cpu and measure the temperature dropout at the board level, underneath the cpu, to determine if this is enough to effectively semi-melt the solder points.

The plastic parts of the motherboard are heat resistant EXCEPT the small black rubber cap over the microphone, this must be removed prior to heating.

I'll update the thread once i have the results.[/QUOTE]

I appreciate your thoughts , I was concerned about the heat gun method, and would agree it will be a last resort if ever at all. I am anxious to hear the results of your tests with the oven and hoping it turns out to be a viable option for those of us without access to the proper equipment.

Many thanks for your work on this....
[HD2 General] booze_pistol:
I was just looking on eBay and found SMD rework stations for $89.95 shipping included. That is a lot cheaper than I remember them being. The specs on the units look pretty good. Since I am new here not sure the policy on external links or I would post it. Since I have two phones that would equate to $45 each, and the advantage of having a rework station for other projects I have ongoing. That 30 PIN TSOP i just did would have been a breeze with a rework station.

Even with a rework station there is no guarantee of success, but it is definitely more controlled and on this thread 3 phones have been successfully repaired with this method. Just thought I would pass it along.

Specs on the unit mentioned:

Air pump type	diaphragm pump

Temperature	100 degree C to 600 degree C

Air flow	<= 28 L/minute

Display type	LED display

Power consumption	600 Watts

Soldering Hot Iron Specifications:

Temperature	150 to 500 degree C

Power Supply	AC 110V 60 HZ

Display type	LED display

Output Voltage	24V AC
[HD2 General] motoi_bogdan:
ah, those crappy china ware smd rework station. I have one of those, you really must be some sort of a jedi master to effectively use that thing. During the years i've developed a 6th sense about how much to heat, the air speed and temperature since the information displayed aren't by no means reliable.

In my opinion good soldering skills, be it with a smd rework station or with a soldering iron, develop over some couple of years of practice. I solder for as far as i know, some good 17 years and still have problems with some pcb's and specific solders.

However, it's a good smd station for that price. It will help you develop the feel for this type of soldering. If you manage to use that thing and work with it, when you switch it for a more professional model, you'll be some sort of "The King of the BGA realm" :D
[HD2 General] booze_pistol:
Haha yeah i'm sure it is china made, whats not these days huh? It has been Labeled with an American name, and being sold by an US seller, for what little that's worth.

I have been soldering for about 25 years. Never once with a SMD station though. It ages me but in the beginning boards were single layer, and you could actually troubleshoot board level with little more than a meter, you were a rocket scientist if you actually had a scope!. The only single level board I've come across in years now was the PS board in my plasma TV. Most everything is multi-layer surface mounted these days.

I may buy one of these units, not certain yet. Guarantee you if I do, repairing my HD2 will not be the first thing I do with it. I have plenty of PC motherboards and laptop boards I want to remove parts from. Scavenge from one to fix another kind of things. Get some experience with the unit try to figure it's bugs out, and then maybe I would tackle the HD2

I'm still hopeful your oven experiments will garner some good news, time and age have made me patient, my phones aren't going anywhere.
[HD2 General] DJ_MiX:
I got me a KADA 852D+ and very happy with it, just like all new devices practice till you feel confortable not all behave the same.

Comes in handy for repairing usb ports on phones.

Aoyue 968 is good has more power in watts than the KADA 952 but I'm happy with it.

One day I will get me a infrared unit, but the KADA works great and I don't do many PC work that requires reballing chips, so will see.
[HD2 General] DTNT:
I think you go off-topic. Please post issue related ideas. Thousands of people waiting for it at their gas-ovens!!! :)