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Solving the thermal problems of HD2 or other snapdragon powered devices

OP motoi_bogdan

26th March 2011, 05:01 PM   |  #21  
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i did all of ur steps bu the same,the same thing,but i found something,the device stop freezing,just restarting then stuck at green htc ,what do u thing the cause for?
26th March 2011, 05:08 PM   |  #22  
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About advertisement we can ask news writers to give us a hand? good idea?
26th March 2011, 07:01 PM   |  #23  
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Quote:
Originally Posted by abufaris

i did all of ur steps bu the same,the same thing,but i found something,the device stop freezing,just restarting then stuck at green htc ,what do u thing the cause for?

please be a little more explicit.
as i understand, after making this intervention, the device still didn't work but the manifestation of the problem changed?

If i get it right and from what i know already, you improved the cooling but for some reason it was not enough. Phone locking or 7 vibrates in a row is worse then simply restarting as i experienced on mine's. Example : if i tried to induce the problem at the start of my experiment, i wound notice first that the phone would start to restart itself, then after 4-5 restarts in a row i would end up with the phone locked either at start-up or in an application.

Also, if the problem damaged the BGA connections severely and has progressed beyond a certain point, simply cooling up the cpu won't suffice as the damage to the BGA connection is still there and already done. In that case only reheating could help but again, that carries the risk of destroying the BGA soldering if done improperly or simply if you aren't lucky.

At first, try to lower the temperature at witch you experiment with your phone. Say.. 10 degrees lower then now, does it still restarts? 20 degrees (in the freezer) does the problem still happens?
This will show you how close/or how far you are from a temperature that the phone in it's current condition can handle.
26th March 2011, 07:48 PM   |  #24  
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I've done mine exactly as you described but without mica foil, just aluminium sheet and thermal paste.

no go for me but i am not professional, so anyone should be lucky i guess?

was restarting at 35degrees, now at 32.5
26th March 2011, 08:37 PM   |  #25  
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i'm sorry to hear that. it's true that having seen various thermal designs i got some sort of feeling about how things should work. However if the temperature limit needed to induce the problems has now fallen to 32.5 it seems you somewhat worsen then heat transfer from the chipset to the cooling system.
One more word, the problem isn't related to a thermistor unit inside the cpu, telling it to restart at either 35-40 degrees or such sort of values. From most CPU datasheets i've read, most semiconductor made devices should take up at least 75-80 degrees without ANY damage to themselves. desktop sized cpu's, simple transistors on other similar equipment can withstand 105 degrees core temperature without silicon oxidation ocuring.
I only wish to state another thing. You aren't actually trying to cool down the cpu, you're trying to cool down the soldering between it and the board. The cpu can take the heat, the board is designed to take the heat, but the soldering is the weak point here. When temperature increases those small BGA balls tend to dilatate and break electric contact. That's the real problem. I can't dismiss the effects of heating the cpu with a solder station (although it didn't solved my problem by it alone, it surely ameliorate the temperature threshold at witch the restarts/freezes are ocuring).
Pressure is also relevant, although it doesn't seem obvious in my pictures, there's quite a big amount of pressure on the cpu&board because of this cooling system and the mica pads (i still consider them essential to this design - heat transfer is waaay better then thermal paste or aluminum.. they are simply made for this).
Pressure can force the BGA soldering to stay in position, there is a chance, not sure about this but it can contribute. Also... it took me about 3 hours of tweaking with the positioning and pressure aplied by these materials in order to finally get to that specific configuration. Most tests were made with the motherboard exposed and temperature was measured directly at the board level.
Don't give up but never stop to work carefully when dealing with components, the motherboard and such sensible things.

At worst, if this fails completely and i was just a lucky example, this will provide some prof of serious hardware failures and bad design from HTC to this phone. Also, for those who are trying such procedures, try to document what you are doing (pictures, measurements), it will be easy to understand these problems and their real cause. I supose i will also have to disassemble mine, because... well.. i did use some crappy thermal paste and the thing is like pouring out from the back of the unit, lost it's consistency and looks pretty weird. I'm sure that the guts of the cooling "system" will still work fine but... it looks ugly to see something oily around the battery compartment. (used industrial level thermal paste)
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26th March 2011, 09:39 PM   |  #26  
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first i should thank u for great job,and my story started with my hd2 when the gps signal gone away,i always using igo8 and it was normally since i noticed that the phone has no gps signal,,,,start to change the rom, but the same,after that i went to load wp7 roms into device,and, the heat broblem started with,the device start to be hot and hot,freezing ,then i back to win mo 6.5 ,with the same issue,i did the whole steps of ur thread,i can feel the heat come from back of the device,even i put some thermal grease with meca foil to the back,but the same,
any way i used a TYTN2 (kaiser) for three years without facing any troubles like that,HTC should bee responsible for here job,`HD2 was like a dream for me to have,and i pay for around 800 dollars, because we dont have here any HTC dealer,only black market,my money now gone with the wind,the phone become like a toy,only receiving calls,no gps,no application,even no more games
i send HTC company a letter and they said u should send it to us by mail to the HTC global,and the will examin it,if need any repairing i should pay money for,****...
any way the only solution for me is keep looking around the internet for some solutions for my problem,and i think i am not alone here,

is there any possibility to place tiny fan i know u will laugh now,but its an idea




thank u
Last edited by abufaris; 27th March 2011 at 09:39 PM.
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27th March 2011, 11:45 AM   |  #27  
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sir my hd2 restarts at 32.5 degres...do i need to do the 3rd optional step ?? I hav never done such thng b4 ... I hav made available evrythng excpt mica crystal pads because i live in a village in india so stuck at this step..!
29th March 2011, 08:34 AM   |  #28  
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@harrrysekhon well, your phone is almost as worst as mine's before the procedure. Mine was also restarting around 30-32 degrees so.. no navigation, no video playback, no intesive apps&games no nothing.

Before even thinking about reheating, check the following.

There is a distance between the cpu chip and the metal shield above it. They don't come in to contact by default. That distance MUST be filled, therefore i used the mica pads i was talking. What did you used in your case?
Please take note that this is the most important step in this setup. Heat must be taken away from the cpu, the job must be done effectively. On my first testings, if the mica pads weren't in good thermal contact with both cpu and metal shield, the thermal performance of the cpu actually got worse or remained the same (still restarting). I did the testing with the phone's case opened.
Great care must be placed in that area, i have not tested anything but mica pads for i know they are best suited for this purpose.
Also a fair amount of pressure must exist between the display's back, the cooling system and the motherboard. This will allow a good contact between the various elements of the cooling system. Too much pressure isn't good however, as you risk either breaking the display or making it more vulnerable to break in the event of a mechanic shock.
4th April 2011, 06:43 AM   |  #29  
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Great job compiling this info... I have hangs and reboots with the 7 vibrates of death at about 31-33, got it damaged, second hand also, I am going to try your 'heatsink' idea this week... I will report back when I attempt it...

found some tp-220 mica pads on mcmelectronics.com ordering in the am....
Last edited by mmaiolo81; 4th April 2011 at 07:04 AM. Reason: added info
4th April 2011, 02:31 PM   |  #30  
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i first thought of this as a last resort option for HD2.
The normal procedure would be to de-solder the qualcomm chip and reball it, then re-solder it back. This is kind of impossible because there is no BGA former for this chip in order to place the solder balls on it. Furthermore... there is that resin that prevents removing the chip as it melts at a higher temperature then that of the solder joints. If the chip would be heated at that level it would most probably die out from overheating.

So, with a motherboard replacement as the single most viable option, i had nothing to loose when i first attempted this "mood" (i could not use a phone that cannot work at 25-30 degrees ambient temp).
This procedure includes some experiments, proper placement of materials, it's a bit trial and error. Once it was done, it saved my phone, but as being the single example of this working, i can only state that results can vary.
Try to apply some sort of pressure between the cpu, it's metallic shield, the custom made cooling system and the back of the display. All those components must be in perfect contact from a heat transfer point of view. Pressure is almost as important as the cooling system itself, but too much of it can be dangerous for the display - you have something hard pressing on the back of it, thus making it more sensible to outside pressure (more likely to break in case of impact or some mechanical shocks). In my case, if i make a heavy push on the buttons, there are some color spots that appear on the display suggesting pressure is being made on that area. The spots aren't permanent and i never push hd2's buttons that hard - to make those things visible, so it's not a problem on it's self. But it's an indicator on how tight things are inside there

Good luck and i'm hopping for good results.

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