Bitcoin Forum

I just got my two Antminer U2 and followed this guide (https://bitcointalk.org/index.php?topic=437666.msg4809020#msg4809020) to set them up, but ran into a problem:

Wether i use a batchfile or start bfgminer manually without options and setup in the program bfgminer's window will disappear after a short while of mining. The process though remains active as i can see via the taskmanager.

What culd be causing this?

Details: Win 7 64 bit, BFGMiner 3.10.0 64 bit, mining on eu-stratum.btcguild.com. The two AMU's are connected directl to the PC via the onboard USB slots using lengthening cables. So far i only ran with default clock (x0781) via batch (since you cannot set the clock in bfgminer itself I suspect it uses that setting aswell when I just start BFGMiner and setup the devices in the manager).

could underclocking be the key?

Hmm okey, starting just bfgminer and using antminer:all instead of AMU:all in device manager did the trick and it now runs stable.

I'll see if the same works with the batchfile aswell.

Yep changing the batchfile from amu:all to antminer:all worked.

Now I need to figure out how to get the temp of U2's so i can see about cooling because the get quite hot even at 1.6 clockspeed.

Weird. The Antminer U2 is an improvement over the U1, and it should be able to run at 2GH/s without overclocking and issues.

Actually sources differ on that. The sheets from Bitmain themselves to my knowledge still say the U2 is meant to run at 1.6 GH/s the update is that overclocking beyond 2.0 GH/s is possible without modifications beyond additional cooling. The U2+ with the bigger cooler on the back is meant to run 2.0 GH/s by default and is said to be able to run stable at 3.0 GH/s with according cooling measures but i haven't found a supplier for those in germany yet. At least that is what I gather from all the different threads about them here.

The two sticks I have here get so hot at 1.6 GH/s already I do not dare running them at higher freq without getting additional cooling running.

As I wrote earlier the problem wasn't with the chips the problem was indeed using the wrong parameters to select them as devices.

U2 does not report temp. it is not in the firmware and they do not have a sensor.

Yeah looking into getting an eternal solution.

   If you want the miner to work at default speed then you do not need to enter one at all,  not sure if that may cause additional heat unnecessarily. While some people prefer the batch file to launch, you can tell BFGMiner to write a config file from the console after your running. 

Cool. I didn't know that (BFGMiner documentation seems a little incomplete or i have overlooked that). Is it also possible to set the clock speed at runtime? Haven't found an option for that in the Menage Devices part.

Ok now I ran into another problem. I've been running the U2s at 1.4 GH/s for a while because the were getting so hot. Because people now stated numerous times that 1.6GH/s shouldn't be a problem even when the get quite hot I wanted to run them at 1.6 GH/s. So I started them with the higher clockspeed only to find that one of the two would become etremel slow after a while (0.5 GH/s). when back at 1.4 GH/s setting the both run fine again. Any Idea what could be causing that?