Bitcoin Forum

Just got mine today and plugged it in, after about 5 min i couldn't touch it-it was so hot.

So put a fan next to them.

Yes, they get very hot.  As long as nothing is resting on them, they are fine.

Use also a heatsink glued on the ASIC chip.
http://ct1aic.dyndns.info/USB_Block_Erupter_heatsink.jpg

It's small and simple.
It nearly has not any designs for heat radiation.

So pay attention to its defects liability period and rules.
Heat radiation could be a big problem for hardware.    ;)

Just have a small movement of airflow across the miner and you will be fine. I speak from experience. No airflow is bad. Some airflow is better. They stay nice and cool with a small breeze to help cool them down. Good luck mining!

I've been running one for a few weeks with zero active airflow. It's just dangling on a USB hub next to my desk. There's nothing else hot around it, and I wouldn't run several close together with no flow, but this one is doing just fine. With an IR gun, I'm getting up to 175 degrees F on the ASIC itself, and about 155 across the heat-spreader on the back.

I only have 1, and it gets too hot to touch. Its been hashing along 24/7 for weeks with no issues. 

Too hot to touch? well, don't touch it then.  problem solved.  :P

Glued? I hope you meant thermal paste. Im pretty sure that glue is a bad heat conductor you dont want between the to cooled chip and the heatsink.

Where can you get these heatsinks and (thermal?) glue?

fingers are NOT good for measuring chip temperatures. CPUs and GPUs can run well into 70s without any damage. Wikipedia states:
So don't get worried if it's too hot to touch. It doesn't necessarily mean it's hot to operate.

I mean 3M like thermal tape. See next post for the link to the heatsink kit, SebastianJu.

I bought a Raspberry Pi heatsink kit, that includes a 6x8mm and a 8x8mm heatsinks, both good for the USB Block Erupter ASIC chip.

The kit includes the thermal tape needed to "glue" the heatsink to the ASIC chip.

I spoke with the seller about this USB Gizmo and he is trying to have a selling of a 6x6mm heatsink. I'm still waiting for news from him.

Meanwhile, this is the link to the eBay selling kit if you would like to buy it, tlr: http://www.ebay.co.uk/itm/121059845105?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

Put your coffee cup on it.  ;D

i run four of them off a USB3 hub and I have a usb powered fan washing air over them and they seem to be running alright. If you're really worried, use a tower PC fan, you can buy them cheap and power them either of a psu or with a cheap 230AC/12DC converter (the ones on the bigger christmas lights are more than sufficient.

I have attached heatsinks to mine with just some Arctic Silver 5 thermally conductive paste.

You could use thermal adhesive (which dries like a glue and can't really be removed) but I would not recommend it as the heatsink will be more or less permanently bonded to the chip. If you tried to remove it you'd risk snapping the chip off the board.

http://www.arcticsilver.com/as5.htm

http://www.arcticsilver.com/arctic_silver_thermal_adhesive.htm

I use these fans http://www.amazon.com/gp/product/B008LHBCQA/ref=as_li_ss_tl?ie=UTF8&camp=1789&creative=390957&creativeASIN=B008LHBCQA&linkCode=as2&tag=smamedgro-20 (http://www.amazon.com/gp/product/B008LHBCQA/ref=as_li_ss_tl?ie=UTF8&camp=1789&creative=390957&creativeASIN=B008LHBCQA&linkCode=as2&tag=smamedgro-20)

Hm... i now searched google and found different opinions. Most claimed that thermal paste is far better than thermal pad. But another one claimed that he measured the opposite.
I tend to believe that thermal paste is better since i doubt that a tape can be a better heat conductor than a fluid of metal. On the other hand... its not so important in this case of use.

I put in front of a fan i have aimed at a GPU rig, with that they haven't got hot to touch once.  Not the most power efficient cooling wise.  But if you have a GPU rig still running works great.

I have come up against this problem with trying to cool high power VRM's with poorly fitting waterblocks on cards like 5970's. The simple fact of the matter is that those grey silicone(?) thermal pads (which often tear extremely easily) have 'good' thermal conductivity but as only as far as soft compressible materials go. THEY ARE COMPLETELY INFERIOR TO PROPER HEAT CONDUCTORS LIKE ALUMINIUM, COPPER, SILVER METAL by at least a few orders of magnitude. In my experience they are also inferior to good quality thermal pastes.

If you absolutely must use those thermal adhesive pads, try to get ones that are as thin as possible, more heat will pass through it that way giving you better temperatures. Some thermal adhesive tapes are extremely thin but offer good stickiness, these are what you want to use.

Just like with those pads, even thermal paste (and thermal adhesive) can be very problematic if you apply it too thick. There is a very fine line between using too little and too much but hey, it's still better than having air gaps (air being a gas is one of the best thermal insulators).

you realize that silver is a conductor of electricity, right?  I hope none of that silver paste shorted any components on your Eruptor...

Hey Canary and yes I have abused your nice little miners a little bit since I got them but they are still alive :)

You are technically correct that the grey thermal pastes usually contain silver particles which are themselves probably conductive, however a large percentage of the material is actually oils and binder materials (the exact composition is usually proprietary though you can work it out with some acetone, filtering equipment, and precision balances). These binders are generally non conductive so you end up with something that is a less conductive than a single piece of solid metal.

Of course, alumina and other metal oxide based (white) pastes are generally assumed to be entirely non-conductive because most metal oxides are excellent electrical insulators.

Just how conductive is silver based thermal paste? Well I did a quick test, I took some Arctic Silver 5 and smeared it over some perfectly smooth plastic in about that kind of thickness you would use for any CPU/GPU. Then I took some aluminium metal and made two conductors on either side. The conductive path of paste was 50 mm long and 10 mm wide and then I used a multimeter to measure the resistance across the paste:

For the measurement I used my digital multimeter, which caps out after 40 megaohm. Just how much is 40 megaohm? Well its not allowing much conduction at all. I managed to get 7 megaohm measuring between my fingertips on each hand, through my body, pressing very hard on the probe pins. Pushing lightly with my fingertips, I could raise the resistance until it reached 40 megaohms and then finally went over its limit.

The 50x10 mm strip:

• https://i.imgur.com/Unxx70ul.jpg (https://i.imgur.com/Unxx70u.jpg)

However, it did not give any measurement, indicating the resistance was >40 megaohms! I even pressed down firmly on the aluminium to ensure it was in good contact with the paste on both sides.

Not one to give up, I reduced the area to 10x10 mm. Again, no reading was possible as the resistance was far too high.

So I reduced the measurement area to about 10x 0.3 mm, perhaps the spacing of pins you would find on a chip. In the photo, you can barely see the gap between the aluminium conductors its so small:

• https://i.imgur.com/d9WyzkTl.jpg (https://i.imgur.com/d9WyzkT.jpg)

Again, it was suprisingly still >40 megaohms.

I raged, and simply pushed out a glob of AS5 and dug the multimeter pin probes straight into the paste:

• https://i.imgur.com/gXqqBUBl.jpg (https://i.imgur.com/gXqqBUB.jpg)

Still, there was no conductivity. I found that even if the metal probes are lightly touching each other inside the paste, there is still no measurable conductivity.
 In the picture above the red probe is actually resting ontop of the black probe, but still no measurement can be had. Only by pushing the tips together fairly hard within the glob can you get a reading (and as you'd expect, when the metal tips actually touch, it goes to <0 Ohm ie. the other limit of the DMM's measurement range.)

This is kind of suprising to some extent but then I realise that I have seen plenty of CPU and GPU where the onchip SMD capacitors have been drowned in thick silver based pastes but still functioned perfectly. In fact in my experience this is an amusing 'problem' that used to be seen a lot with Pentium 3 and 4 equivalent Xeon chips in severs (especially from Dell!). This is kind of like how you can probe pins on a running PCB circuit with digital components using an oscilloscope: because of the high probe inductance/resistance it usually won't effect the circuit/devices operation. I realize that at kHz and above frequences other electrical effects in seemingly non-conductive materials become considerable though I think in this case you can get away with it thanks in part to the design tolerances of the components and signal:noise will probably still be pretty good.

tl;dr - Getting silver thermal paste (at least Arctic Silver 5) on pins / exposed parts of CPU/GPU/ASIC has no effect on the performance.
Edit: In the overclocking thread I have discovered (https://bitcointalk.org/index.php?topic=241652.msg2793903#msg2793903) that capacitive effects from AS5 actually DOES cause problems with the USB miners. However I found that Ceramique 2 compound worked fine, although it too would have some capacitance so YMMV. The optimum solution seems to be using 2 sided tape.

PS: I scraped some 'dried' thermal paste off some scrap sever CPU heatsinks and measured the resistance of that, and again it was the same. The conductivity doesn't really increase in any measurable way when the paste has set/dried.

(Disclaimer: A few manufacturers, including Arctic Silver inc, discourage you from getting it on exposed pins/components because of the other electrical effects I mentioned above. Don't assume from my shitty 10 minute tests that your $$$ device won't implode if you're messy with paste.):

AS5 instructions (http://www.arcticsilver.com/pdf/appmeth/int/vl/intel_app_method_vertical_line_v1.1.pdf):

Although this argument is all kind of irrelevant... because its easy to not make a mess with the thermal compound and avoid getting it on the pins, but also because the ASIC die is apparently positioned upside down relative to how die are usually set in epoxy on a CPU/GPU. As a result, cooling is actually superior through the PCB and into the heatspreader rather than putting a tiny heatsink on the topside of the ASIC. See my link above in the overclocking thread for more info. That's why the manufacturers went with a heatspreader under the PCB instead of shipping them with a tiny heatsink ontop.

There must be no silver in that paste!! They lied to you. LOL
Hey, nice testing!  ;D

I'd throw some in a SEM and do some elemental analysis.. but I have a damned thesis to write!

UPDATE: http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=121148027445 (http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=121148027445)