Post Reply

[MOD] A700 Heat & a Viable Solution!!!

27th June 2012, 03:56 AM   |  #1  
Beknatok's Avatar
OP Senior Member
Flag Chicagoland Burbs
Thanks Meter: 118
 
413 posts
Join Date:Joined: Dec 2008
More
UPDATE:

I wish I'd done some temperature benchmarking beforehand, but instead sourced the community to help out. Check out the various results on XDA... there are also results from two TF700 owners (in Europe) who were gracious enough to help me out.

http://forum.xda-developers.com/show...php?p=28051518

First, it seems clear that my mod really didn't mitigate the heat issue enough... so don't bother.

Second, comparing the numbers between other A700's and the TF700... well, I'll let you draw your own conclusion on that one. :(

---

Hi all,

As many of you have experienced, the A700 can get very hot under certain conditions. Mine got extremely hot to the touch after just an hour of gaming (Heavy Gunner, NFL Flick QB, and Cut the Rope), and crashed 2 or 3 times.

Well I decided to do something about it. Reading through the Service Guide (thank you paugustin!!!) & A700 teardown photos from another site, I came to some conclusions. First, from the looks of things, the back panel has some kind of metal plate lining, and 3 "pads" that closed the gap between the metal plate and several surfaces of the mainboard. My hope was that these pads were not simply foam pads but were actual thermal pads. I guessed that a bit of thermal paste might help the efficiency of those thermal pads... and if I got really ambitious, I could replace the thermal pads with larger ones (and paste those too).

Service Guide:
http://forum.xda-developers.com/show....php?t=1716922

I followed the instructions in the Service Guide & opened up my A700 earlier tonight. I'm pleased to report that as long as you take your time, it's super easy to open up.

And lo and behold, my conclusions were accurate... the back plate is copper and the pads were thermal pads!

Back Plate:
https://www.dropbox.com/s/um556g6vtl...6-20-14-30.jpg

MainBoard:
https://www.dropbox.com/s/jka8gooiyq...6-20-14-46.jpg

Closer Look @ the Thermal Pads:
https://www.dropbox.com/s/0j4e7wjfod...6-20-15-06.jpg


I took some CPU thermal paste I had lying around & dabbed some on:
https://www.dropbox.com/s/kvv99k3ghx...6-20-17-24.jpg


Afterwards, I slapped everything back together, fired up NFL Flick QB and played for a half hour. I'm pleased to report that the A700 got warm but nowhere near as hot as it did in my prior gaming session. The "level of warmth" was what I'd consider mildly warm, comparable to my fiancee's iPad3, so definitely within reasonable tolerances.

I still intend to put the A700 through some more intense gaming tomorrow, but I wanted to write this post up and share it with everyone first. Hope folks find this useful and insightful!
Last edited by Beknatok; 29th June 2012 at 02:31 PM.
The Following 8 Users Say Thank You to Beknatok For This Useful Post: [ View ]
27th June 2012, 06:29 AM   |  #2  
FloatingFatMan's Avatar
Senior Member
Thanks Meter: 537
 
2,663 posts
Join Date:Joined: Apr 2005
More
Nice discovery, but yikes! Thermal grease is meant to go on in a translucently thin layer or it ends up having the opposite effect! If you put that much between a CPU and it's cooler, you'd kill the CPU! :S
27th June 2012, 11:12 AM   |  #3  
Member
Flag Cologne
Thanks Meter: 6
 
64 posts
Join Date:Joined: Feb 2012
More
superawesome!

Yet still i'd like to wait for more people to evaluate the hardwaremodding before i go in there myself.

Still, kudos to you.
27th June 2012, 02:10 PM   |  #4  
Beknatok's Avatar
OP Senior Member
Flag Chicagoland Burbs
Thanks Meter: 118
 
413 posts
Join Date:Joined: Dec 2008
More
Quote:
Originally Posted by FloatingFatMan

Nice discovery, but yikes! Thermal grease is meant to go on in a translucently thin layer or it ends up having the opposite effect! If you put that much between a CPU and it's cooler, you'd kill the CPU! :S

Except in this case, the thermal grease isn't going up directly against the CPU... it's going up against a thermal pad & large metal plate that is covering the entire mainboard.

Additionally, unlike a heatsink & CPU which are fitted together tightly, the back panel of the A700 & thermal pads do not contact anywhere near as tight to the mainboard plate. I fitted the two halves together, then pulled them apart again, to see how much the paste really spread out. This way I could better gauge how tight the contact was & remove any excess that got squished out. However, not much paste really did, telling me that the compression between the two isn't that great. That is why I'm toying with the idea of replacing the thermal pads entirely.
27th June 2012, 03:01 PM   |  #5  
Senior Member
Flag Somewhere Else
Thanks Meter: 262
 
850 posts
Join Date:Joined: Sep 2007
More
Hey, good stuff. Keep us in the loop on this....

Thicker thermal pads might be in order, or a better paste job under the plate on the CPU/GPU...

Bigger pads to spread the heat out more since the back looks to be one copper heat sink..

http://www.frozencpu.com/cat/l2/g8/c...Pads_Tape.html
Last edited by Itchiee; 27th June 2012 at 03:06 PM.
27th June 2012, 03:58 PM   |  #6  
Senior Member
Thanks Meter: 278
 
3,126 posts
Join Date:Joined: Jan 2008
Quote:
Originally Posted by Beknatok

Hi all,

As many of you have experienced, the A700 can get very hot under certain conditions. Mine got extremely hot to the touch after just an hour of gaming (Heavy Gunner, NFL Flick QB, and Cut the Rope), and crashed 2 or 3 times.

Well I decided to do something about it. Reading through the Service Guide (thank you paugustin!!!) & A700 teardown photos from another site, I came to some conclusions. First, from the looks of things, the back panel has some kind of metal plate lining, and 3 "pads" that closed the gap between the metal plate and several surfaces of the mainboard. My hope was that these pads were not simply foam pads but were actual thermal pads. I guessed that a bit of thermal paste might help the efficiency of those thermal pads... and if I got really ambitious, I could replace the thermal pads with larger ones (and paste those too).

Service Guide:
http://forum.xda-developers.com/show....php?t=1716922

I followed the instructions in the Service Guide & opened up my A700 earlier tonight. I'm pleased to report that as long as you take your time, it's super easy to open up.

And lo and behold, my conclusions were accurate... the back plate is copper and the pads were thermal pads!

Back Plate:
https://www.dropbox.com/s/um556g6vtl...6-20-14-30.jpg

MainBoard:
https://www.dropbox.com/s/jka8gooiyq...6-20-14-46.jpg

Closer Look @ the Thermal Pads:
https://www.dropbox.com/s/0j4e7wjfod...6-20-15-06.jpg


I took some CPU thermal paste I had lying around & dabbed some on:
https://www.dropbox.com/s/kvv99k3ghx...6-20-17-24.jpg


Afterwards, I slapped everything back together, fired up NFL Flick QB and played for a half hour. I'm pleased to report that the A700 got warm but nowhere near as hot as it did in my prior gaming session. The "level of warmth" was what I'd consider mildly warm, comparable to my fiancee's iPad3, so definitely within reasonable tolerances.

I still intend to put the A700 through some more intense gaming tomorrow, but I wanted to write this post up and share it with everyone first. Hope folks find this useful and insightful!

Fantastic for the XDA community, but the average buyer will be like the cheesey pop group Power Station and will "Feel the heat".
27th June 2012, 04:37 PM   |  #7  
Beknatok's Avatar
OP Senior Member
Flag Chicagoland Burbs
Thanks Meter: 118
 
413 posts
Join Date:Joined: Dec 2008
More
Quote:
Originally Posted by rushless

Fantastic for the XDA community, but the average buyer will be like the cheesey pop group Power Station and will "Feel the heat".

Then be happy that you're amongst the enlightened!
27th June 2012, 06:37 PM   |  #8  
Member
Thanks Meter: 44
 
85 posts
Join Date:Joined: Jun 2011
Exclamation
CAUTION!!!!!

OK maybe that's a bit strong, but as an engineer I have to question the logic employed.

First of all, the heat generated by the CPU, battery, etc. must exit the device. ALL OF IT!

Temperature of the back plate is determined by two factors alone: thermal resistance (e.g. insulation, heat pipes, air flow, fins, etc.) and the amount of heat transfer. I'm serious!

It appears that you have done nothing to affect the thermal resistance between the back plate and the air (e.g. adding cooling fins or increasing air flow). Therefore if your back plate temperature has decreased (and the air temp stayed the same), then we would conclude that heat transfer between the back plate and the air has DECREASED.

If hea
Last edited by yeoldeusrename; 27th June 2012 at 07:07 PM.
The Following User Says Thank You to yeoldeusrename For This Useful Post: [ View ]
27th June 2012, 07:08 PM   |  #9  
Member
Thanks Meter: 44
 
85 posts
Join Date:Joined: Jun 2011
If heat transfer from the plate to the air has decreased, then that means the heat transfer from the CPU etc. to the plate must have decreased as well!

My guess is that your thermal paste is producing a higher thermal resistance, as predicted by FFM! And it's deceptive because it's insulating the back plate from the CPU etc.

So where's the heat going? (I hear myself asking... myself.)

My guess is that it's dissipating through the tablet, getting distributed and absorbed and ultimately emitted more uniformly from the device. This would raise the internal temperature of the device, including the CPU! Hence the CAUTION!!!!!
Last edited by yeoldeusrename; 27th June 2012 at 07:11 PM.
27th June 2012, 07:13 PM   |  #10  
Member
Thanks Meter: 44
 
85 posts
Join Date:Joined: Jun 2011
Your idea could have some benefit, though, and here's how i see it playing out:

If you decrease the thermal resistance between the CPU and the back plate, then the CPU would be closer to the temperature of the back plate (i.e. lower). But the back plate temperature won't really change because you still have the same total heat coming through and the same thermal resistance with the air.

As for spreading the temperature across the back plate more, I'm not sure you can do it more effectively than the copper plate that's already there. Not without insulating the most direct heat transfer path!

Post Reply Subscribe to Thread
Previous Thread Next Thread
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes