Cozyswan S400 heatsink fix [image heavy post]

[marcusbrutus]

Hi everyone,
I bought the Cozyswan S400 on **** some time ago, and even though I tried underclocked kernels, I was thwarted by the inadequate heatsinking to the point where it would continuously reboot.
I needed a solution for a new screen (for monitoring security cameras in the kitchen!) so I decided yesterday to fix the S400's heatsink.

Scratching through my heatsink box I eventually found a Pentium 200+ cooler

and cut it to shape.

The face was polished with fine sand-paper, wet&dry, melamine sponge, and then cardboard,

and reliefs cut for various onboard components like the reset switch, the HDMI plug and SMD resistor.



Noticing that the CPU was actually higher than the memory chips I then filed down the CPU-half of the heatsink by about 0.5mm (wild guess).

Note that this is extremely difficult to get *perfect* with just hand tools, so some degree of a "near enough" attitude might be required ;-) .

Next a hole was cut in the cover,

and then shaped to JUST fit the heatsink fins.

The fit needs to be tight in order to apply pressure to the chips. The heatsink inserts into the hole without pushing it all the way in.

Heatsink paste is applied

and then spread to form a thin film over both the heatsink (hard to see in this light)

and the chips.


Now the cover is carefully squeezed into place so that the cover sits flat and still pushes the heatsink down:


Complete set of photos (taken using HDR mode on a Tronsmart TS7 mobile phone: http://www.geekbuying.com/item/317183.html )
are here: https://plus.google.com/photos/11302...CIC3k8eszpLwKQ

To finish off, I tested with the Classic Stability Test within Stability Test v2.7 https://play.google.com/store/apps/d...into.stability .
Note that the system was still running a 1200Mhz underclocked Sam321 kernel with the NeoMode ROM installed during my previous efforts to get this machine stable (props to Sam321 http://www.freaktab.com/archive/index.php/t-5412.html and neomode http://www.freaktab.com/archive/index.php/t-5494.html )
After 1.5hrs the heatsink was quite warm, but the system was still responsive and running perfectly.
I assumed that the test was continuous and left it running overnight.
The next day the screen showed the Stability Test menu screen, the heatsink was barely luke warm, and the system had obviously stayed up the entire night after completing the test.

I'm very happy with the result and *may* change the kernel later if it turns out to be too slow to display multiple video streams, but at this point everything looks good.
ie: working as it should

I hope this post helps others to fix their S400's.

Regards,
Marcus.

[leolas]

Re: Cozyswan S400 heatsink fix [image heavy post]

Great work!! For sure you give an extra circle life to your stick.

leolas.

[marcusbrutus]

I've since tried the latest (dated 04/09/2013) sam321 "720p no overclock" kernel but aborted as wifi and bluetooth didn't work on my device.
Next I tested the previous (dated 30/07/2013) sam321 "720p no overclock" kernel.

1. The CPU+GPU test, which uses a single core ran at 1608MHz with fps ranging from 20-60 and had skips in the scene rotation, had the heatsink running warm after an hour.
2. The CPU test, which runs all four cores at 1416MHz, had the heatsink uncomfortably hot to touch at times, but continued to run without issue for an hour.

Now I'm testing a moderate overclock (dated 18/06/2013) sam321 "1.7ghz ram 1000mhz" kernel.
Early results:

1. The CPU+GPU test appears to skip a fair bit and is only running at 1200MHz on a single core.
2. The CPU test only runs at 1416MHz on all four cores.
3. I've left it running the Scaling test, but with low = high = 1704MHz. After a few minutes it's reasonably hot to touch.

If it survives this test I may go higher, but if not I'll be tempted to splay the heatsink fins and retest ... we'll see!

Note that I don't know how good or bad this stress test is, I'm really only interested in generating heat!

[CrAcKeZ]

I've since tried the latest (dated 04/09/2013) sam321 "720p no overclock" kernel but aborted as wifi and bluetooth didn't work on my device.
Next I tested the previous (dated 30/07/2013) sam321 "720p no overclock" kernel.

1. The CPU+GPU test, which uses a single core ran at 1608MHz with fps ranging from 20-60 and had skips in the scene rotation, had the heatsink running warm after an hour.
2. The CPU test, which runs all four cores at 1416MHz, had the heatsink uncomfortably hot to touch at times, but continued to run without issue for an hour.

Now I'm testing a moderate overclock (dated 18/06/2013) sam321 "1.7ghz ram 1000mhz" kernel.
Early results:

1. The CPU+GPU test appears to skip a fair bit and is only running at 1200MHz on a single core.
2. The CPU test only runs at 1416MHz on all four cores.
3. I've left it running the Scaling test, but with low = high = 1704MHz. After a few minutes it's reasonably hot to touch.

If it survives this test I may go higher, but if not I'll be tempted to splay the heatsink fins and retest ... we'll see!

Note that I don't know how good or bad this stress test is, I'm really only interested in generating heat!

I can get you some Athlon XP's which I have laying around and create a better heater

[marcusbrutus]

Well, after two tests both failed it turns out that the sam321 "1.7ghz ram 1000mhz" kernel lasted 25 minutes.
The log shows that it completed 214 CPU test runs, and 364 RAM tests in that time.
An admirable effort, I figure.

I've thought about splaying the fins, which I'm certain would help, but if there's no significant change I won't be able to go back to straight fins.
I could probably put a small fan on/near it to find out how marginal the heat dissipation is, but there's still no way of measuring or translating this to a splayed design.

Still, given that normal use won't use all cores at max speed for such a long time I think I'll leave it with this kernel for now and see how it goes.

[TVDroid]

Hy

What Kernel you use now ?
Here my MOD ...