Hi all!
After seeing how to fix the S7300 with a penny, I tried my luck with my local currency: euros. Here's the story/guide.
The right coin
Every euro coinsThe obvious choice was to go with the copper looking coins, as copper is known to be an excellent thermal conductor (high ends PC CPU heatsinks are made out of this metal), only silver does a better job (and that's why silver teaspoons are a shitty idea). But can the look be deceiving? Let's check.
- 5, 2 and 1 euro cent coins aren't solid copper at all (neither are US pennies?, BTW). They are actually made of steel, which is terrible at conducting heat, with a thin layer of copper. Yeah, that's bad.
- 50, 20 and 10 euro cent coin are, them, made of Nordic Gold, an alloy containing 89% copper! The remaining 11% are 5% aluminium (which is a good thermal conductor), 5% zinc, and 1% tin.
Looks like Ma was right about that book cover thing.
So 10 cent it is!
Disassembling the beastWe only need to remove 2 PH00 screws at the bottom of the device and pull the back cover which is staying in place thanks to smalls tabs all around it. Getting a grip of the cover is hard, so I used a suction cup. You should be able to do it by using a screwdriver as a lever, at the risk of damaging the case.
JXD sure loves adhesive tapeNow is a good time to check for the device build date.
March 2013, the month before my order. Smells like new.Now let's find the offensive heat sink.
CPU, RAM, flash memory… all the important stuff are under this metal shieldIt seems that the metal shield doubles as a heat sink for the CPU. But not only it's lacking thermal paste or pad, it doesn't even touch the processor! The only clue we have of its function as a thermal dissipator is that there is spot lacking plastic coating bent in direction of the CPU. Hm.
Checking procedure practicability Does the coin fit?
Like a glove!The coin thickness is worrisome, at nearly 2mm, it's 25% thicker than a US penny. After verification, the fit is tight, but is OK.
That's when I found something curious… it looks like the bare metal spot of the shield isn't exactly opposite to the CPU. Patafix to the rescue!
Also available in blue as "Blu Tack"Let's put a tiny amount of Patafix on the coin.
I've always found Patafix more disgusting than Blu Tack. Who chose snot yellow as a color?Then put back the shield, and remove it to hopefully find where it and the CPU meet.
AH AH!As I guessed, the bare metal spot doesn't match the CPU location. Let's fix this.
Fixing the shieldWith a cutter or exacto knife, cut the plastic coating along the still stuck coin.
Like thisThen peel the coating and clean glue residues with White Spirit.
Like thatMake sure your coin is clean. It's a good idea to file it a bit to get rid of any hard to remove dirt.
Let's put a some thermal paste on the coin.
Mouth wateringGetting the right amount of paste is not as easy as on a flat surface, here the raised rim makes it a bit more difficult. At first I didn't put enough and most of it didn't touch the shield. And after that, I put a tad too much.
A tad too muchTrying to clean the paste in excess was a PIA. Rolls and rolls of paper towel, White Spirit and patience finally did the trick.
Now, let's glue the coin. The idea here is to glue the edge and only the edge. We want all of the heads and tails surface for heat conduction.
That's what glue blended with thermal paste looks like. Did I tell you thermal paste was hard to remove?Now that we know the coin is at the right place and won't move, it's time to take care of the other side.
This time, I chose to put a bit of paste on the coin, and another bit on the CPU.
With a fat bit in the middle.I was worried that the thermal paste would leak over the chips around the CPU. Some thermal pastes are electrically conductive, and mine is some old stuff I've got from god knows where. I didn't tried my luck on this and resorted to the good old electrical tape.
Electrical tape, DIY-ers best friend.Be careful when putting back the shield as there are tiny tiny slots where to clip it on each side.
Easy to miss.It's even harder to put them all with the coin so, here again, time to call the electrical tape to the rescue.
It's quite bulging.Also, don't remove the silver tape (at the top on my picture) as it must be conductive and ensuring the good grounding of the shield.
ConclusionThe procedure does the trick. Clearly, to the touch, heat is less concentrated to one spot and is diffused all along the shield.
But does it make that much of a difference?
I'm not sure. I should have made some tests before and after. In the end I find my S7300 still too hot for my taste.
Is this the best way to cool a S7300?
No. The coin fits really tightly and must put mechanical stress to the CPU. The processor is now a lot more vulnerable to hits on the console backside.
A clever variation of this trick would have been to remove the plastic coating matching the CPU location, putting a thermal pad (no risk of leaking) between the processor and the metal shield and, finally, putting some foam between the shield and the back cover (not all over, but just on the right spot) to keep a good contact without applying too much stress on the chips.
In the end, JXD could have made a lot better on the heat dissipation side. There's a lot of free space inside the S7300 and a slab of aluminium covering the whole innards of the device, except for the battery, stuck to the CPU with thermal paste would have been awesome.
[1] They are made of copper coated zinc, which make them toxic to infants and dogs.
