MK908 Insides + Cooling Mod (WARNING: Pic intensive)

[thesawolf]

Salutations folks,

Finally got my MK908 in and ran it through some stress tests with some of the ROMs available (thanks Finless for your hard work). Tested both tronsmart and finless ROMs and found Finless 1.5 to be the best so far.

From there I did tests with both the 720p and 1080p kernels and found that 720p performed the best while 1080p kernel looked great but definitely needs some kernel optimizations to get it up to par with 720p's performance.

Additionally, I noted the heat issue. It gets incredibly hot and relatively quickly. Well.. that means it's time to make some modifications. The current design of the MK908 is ok with its heatsink but there is no method of venting/cooling aside from the little fan-shaped vent cutouts on either side. Passive cooling just isn't going to cut it. That may be fine for regular 720p use, but I plan on using this puppy for XBMC and need some performance for handling some of my 720p and 1080p content.

So let me take you on a little tour of the insides and out of the MK908 and my little cooling mod project. I've made attempts to put footnotes with each pic so you can extract information like chipset stuff and the stats on some of the things I used in the mod. (Click on thumbnail to enlarge pic for more detail)

1 Just a reference photo next to my SDcard (class-10/UHS-1 if anyone was wondering)	2 Mod components I was going to use (didn't use the copper shims & the 2nd heatsink, see footnotes). Ref room temp of 74.5 F	3 Brushless cooling fan (35mm x 35mm x 10mm 5V 0.23A 2-wire) off **** via China	4 Passive cooling w/1080p kernel running benchmarks. 104.7 F.. actually went > 110 and shut itself off shortly thereafter	5 Casing off, inside top. Heatsink pictured. NO internal antenna attached to case like other MK908 versions
6 Casing off, inside bottom. Reflective "material" pictured.	7 Close up of inside top. Only antenna was pin antenna at end. (see notes)	8 Close up of inside bottom.	9 Close up, side view. Note: ONLY the CPU is attached to heatsink w/thermal paste and there are visible gaps over the other chips	10 Close up, bottom w/out reflector on. Notice the MK908 V3.0 2013.05.13 branding (you might not see, but the board is black too)
11 Bottom, HDMI chip shown (ITE, IT66121FN) FYI: I wear gloves to prevent oils and particulates	12 Bottom, RAM modules shown, notice the lack of antenna attached as in previous MK908s	13 Top, RF (Wifi/BT) chipset pictured (AP6210)	14 Top, Heatsink/paste removed, FYI: paste on my CPU was placed poorly, it had oozed off the onto the board	15 Top, Nand Flash memory pictured (29F64G08CBABA)
16 Top, GPU pictured (Rockchip, RK3188)	17 Top, RAM modules pictured	18 Aluminum Heatsink (50mm x 25mm x 10mm) off **** via USA, cut into 3 pieces due to the varying chipset heights	19 Casing cutout for the heatsinks (after this pic I touched up the edges some more with an exacto knife)	20 "Arctic Freeze 5" graphene thermal paste off of **** via USA. Graphene works well, to me, when used correctly

[thesawolf]

MK908 Insides + Cooling Mod (WARNING: Pic intensive), continued

21 Reassembled with case on (view 1)	22 Reassembled with case on (view 2)	23 Reassembled with case on (view 3)	24 Heatsink cooling w/1080p kernel running benchmarks. 112.7 F.. didn't shut off at all. Heatsinks doing job pulling heat from chips	25 Getting fans ready, label side is exhaust side. Was going to place side by side on heatsinks but went with either sides (see notes)
26 Rigged fans to use USB Need to learn how? http://goo.gl/wi2SH	27 Completed, Top. Used a wire that I run through the screw holes, might replace w/black mini zip ties	28 Completed, Side. Went with air blown toward unit on both sides since bottom doesn't get hot (notes)	29 Everything hooked up.	30 Running 1080p w/benchmarks. 78F (top temp reached 80F, but usually sits around 76-78F) Mission accomplished

NOTES:


2 - I had picked up some small copper shims but realized it was a bit overkill and rather unnecessary since it's just another material to transfer heat through with 2 layers of thermal paste where the 1 layer of thermal paste with heatsink should be suitable as long as the heat transfers into the heatsink. As for the 2nd heatsink, see #25 notes.


7 - Strangely, the little pin antenna seemed to be enough. The Wifi reception in this MK908 is surprisingly good. I get 4-5 Wifi bars (-50 to -40 dBm)
in the same place my Acer Iconia A500 tablet gets 3-4 bars (-60 to -50 dBm).


25 - After looking at the bottom internals, it didn't seem necessary to put a heatsink in the bottom portion since the second RAM modules and HDMI chip don't heat up that much and I could use the cooling fan to push some cool air into the case since the top side cooling fan is just cooling the heatsinks and not reaching into the case.


28 - I was debating which direction to position the fans and decided that fans inward seemed to make more sense since the bottom doesn't heat up and pushing cool air in would flow top-wise and I needed to cool the heatsinks quickly and actively with air blowing directly on them rather than pulling the air off. The air blowing on the heatsinks would vent via some of the fin notches and main channels.

---

Well... now that that's all done, I can start doing some kernel hacking since I've been tracking down some of the various driver sources and just needed a test unit to start working on. Hopefully I can get something together soon and contribute with a CyanogenMod-based MK908 rom since I've made CM roms before for my various tabs and phones already (tho this will be my first AMP). Post if you have any questions about the stuff above. Later folks.

[BillMaudit]

Nice

Hi there,

You did a very nice job !
If someday a kernel allows us to use 1080p without video stutters, I'd like to do some mods to my MK908 too.
Did you already have the mod parts like fan and heatsink ? Or if you bought it online, I'll be glad if you share your sources !

I wish you luck with your CM port !

[thesawolf]

Hi there,

You did a very nice job !
If someday a kernel allows us to use 1080p without video stutters, I'd like to do some mods to my MK908 too.
Did you already have the mod parts like fan and heatsink ? Or if you bought it online, I'll be glad if you share your sources !

I wish you luck with your CM port !

Thanks. Hopefully I'll get a chance to dig through the kernel a little bit and see what I find in there. As for the mod parts, as mentioned in the captions for some of the pics, I picked up most of the stuff off **** from US and Chinese sellers recently. Most of the stuff I found when I searched for the parts by name and spec (ie. heatsink 50x25x10mm). But specifically, I got the heatsinks from a seller named victoryrush, the fans from fristlaptop and the graphene from jackboggs2. I found some decent deals in quantity so I have some extra parts for new cooling mods or other AMPs that I'm considering getting in the near future.

[lewy20041]

wery nice

[yoborider]

Point of View ;-)

Hi ! Nice work, I will study the possibility to use that stick in my fridge ;-)

elsewhere :

for McGyver :

http://en.videotutorial.ro/racirea-eficienta-a-stick-ului-android-mini-pc-mk908/

for scientists, peltier effect !! : https://en.wikipedia.org/wiki/Thermoelectric_effect

Bye,

Yo

[thesawolf]

Yeah.. I could've gone the MacGyver route since I have alot of PC components lying around (PC heatsinks and 12V case fans, etc.). Figured I'd try not to cannibalize parts and go with stuff that were actually sized better for these AMPs. Luckily I picked up enough components in quantity so I can work on modding some more of these things rather than resorting to PC component cannibalism

[Bing]

Very Nicely Done! I too have struggled with cooling this little guy, and got some very decently priced sinks and a 20mm fan from modDIY.com and just finished installing them yesterday. But I very much like the route you took! Well done!

[aakaash007]

cool !

I have experienced same problem and had to go back to 720p and then to 480p for maximum heat reduction ... will think about this idea ...if there is any more practical solution (until a software update )pls post here

[thesawolf]

Unfortunately there really isn't a software solution to heat aside from running your device with less intensive apps, etc. The hardware is set up for basic usage but more intensive things like processing 720p/1080p data uses the CPU and/or GPU more, which generates more heat. Running your CPU at lower speeds with a flexible CPU governor can help some with heat, but once your CPU runs videos, 3D games, etc. it'll start generating hit again as it hits the CPU max frequency.

If you are really having heat issues and don't want to mod your unit, simply putting a fan (any fan.. doesn't have to be a PC fan) pointed at the vent cutouts on the top side of your unit should be more than adequate to cool the device. By blowing air into the vents you help the factory heatsink to cool off faster.

[Jazzy]

:-)

Awesome work and pics! I just signed up looking for more info on my new mk908 and I enjoyed your breakdown and detailed pics. I don't have the skill to modify my unit like you did, but if I did, I'm sure your pictorial here would help me along the way. Everything working stable so far since you modded it? You said you were looking at building a ROM for this puppy. Any progress? Need any testers?

[thesawolf]

Thanks. Things are running stable and cool. I'm really looking forward to working with some of the kernel sources I found for the RK3188's so I can put this cooling mod to the test with an overclocking kernel. But first things first. I've already started working on trying to get CWM working and once I get it working the way I want it to, I'll probably slap it up for some testing and make the git public. Found someone that I believe has their hands on SDK2.0 for the RK3188 tabs and hoping I can talk them into letting me take a look at it to see if it can be integrated into the tree for the dongles. Keep your fingers crossed. (and before someone asks, no.. I'm not going to pass on this contact's info as I don't want to scare them off) If I get something, I'll let folks know.. otherwise I'm still proceeding with building with the current "SDK"

[aakaash007]

thank you

Unfortunately there really isn't a software solution to heat aside from running your device with less intensive apps, etc. The hardware is set up for basic usage but more intensive things like processing 720p/1080p data uses the CPU and/or GPU more, which generates more heat. Running your CPU at lower speeds with a flexible CPU governor can help some with heat, but once your CPU runs videos, 3D games, etc. it'll start generating hit again as it hits the CPU max frequency.

If you are really having heat issues and don't want to mod your unit, simply putting a fan (any fan.. doesn't have to be a PC fan) pointed at the vent cutouts on the top side of your unit should be more than adequate to cool the device. By blowing air into the vents you help the factory heatsink to cool off faster.

yes i think i will have to buy a fan
any way thank you guys for the wonderful sharing

[WangChung]

...

[leolas]

Pics broken to me too