Antminer U3 peaks at 370Mh/s

[Xerber]

Hi guys,

Last Sunday I bought a used Antminer U3. It looked brand new (none of the usual dust deposit on the fan blades or the unit), so I thought I had a pretty good deal.

However, unfortunately its hash rate peaks at about 370Mh/s, far lower than the claimed 63Gh/s. It starts out at 1.3Gh/s and then immediately drops only to end at, and remain at, 370Mh/s. I tried several power supplies (it is currently powered using a 120W 12V power supply) and both CGminer and bfgminer (with and without OC settings).

Also, after further inspection of the unit last night, I noticed that two of the heatsink's screws were damaged as if a wrong size Philips screwdriver was used on them. Fearing that the PCB or chips might be damaged due to overtightening, I disassembled the unit, checked the PCB for damage and applied new thermal paste. Visually, nothing seemed to be out of the ordinary (i.e. no cracks).

Do you guys think I made an error somewhere or did I simply purchase a lemon?

Thanks in advance for your help and input.

[notlist3d]

Hi guys,

Last Sunday I bought a used Antminer U3. It looked brand new (none of the usual dust deposit on the fan blades or the unit), so I thought I had a pretty good deal.

However, unfortunately its hash rate peaks at about 370Mh/s, far lower than the claimed 63Gh/s. It starts out at 1.3Gh/s and then immediately drops only to end at, and remain at, 370Mh/s. I tried several power supplies (it is currently powered using a 120W 12V power supply) and both CGminer and bfgminer (with and without OC settings).

Also, after further inspection of the unit last night, I noticed that two of the heatsink's screws were damaged as if a wrong size Philips screwdriver was used on them. Fearing that the PCB or chips might be damaged due to overtightening, I disassembled the unit, checked the PCB for damage and applied new thermal paste. Visually, nothing seemed to be out of the ordinary (i.e. no cracks).

Do you guys think I made an error somewhere or did I simply purchase a lemon?

Thanks in advance for your help and input.

What commands are you using when running it?   

Also when you say your trying different power supplies did it not come with one?  The U3  should come with a power brick, not the adapter cable to wall.  But it comes with power brick.

[leowonderful]

Hi guys,

Last Sunday I bought a used Antminer U3. It looked brand new (none of the usual dust deposit on the fan blades or the unit), so I thought I had a pretty good deal.

However, unfortunately its hash rate peaks at about 370Mh/s, far lower than the claimed 63Gh/s. It starts out at 1.3Gh/s and then immediately drops only to end at, and remain at, 370Mh/s. I tried several power supplies (it is currently powered using a 120W 12V power supply) and both CGminer and bfgminer (with and without OC settings).

Also, after further inspection of the unit last night, I noticed that two of the heatsink's screws were damaged as if a wrong size Philips screwdriver was used on them. Fearing that the PCB or chips might be damaged due to overtightening, I disassembled the unit, checked the PCB for damage and applied new thermal paste. Visually, nothing seemed to be out of the ordinary (i.e. no cracks).

Do you guys think I made an error somewhere or did I simply purchase a lemon?

Thanks in advance for your help and input.

Cheap power brick is probably the problem

[Xerber]

Hi guys,

My apologies for the late reply. Some IRL familiy stuff happened.

I see now that I forgot to mention that I was running cgminer and bfgminer on Windows 10.

The unit did not come with a PSU. Perhaps the previous owner kept it. At first I attempted several PC PSU's that I had lying around (CoolerMaster, Corsair, Antec varying between 400W and 850W), but had no luck with those.

Ultimately, I lend the U3 to a friend for a couple of days and he had no trouble getting it to run on Debian. He returned the unit last weekend and I had some time today to tinker with it some more. I bought a Pi2 and a 120W PSU, just now installed Raspbian and I got running within 20 minutes using cgminer.

I'm happy that it runs, but I still have no clue where I went wrong with the Windows versions of cgminer and bfgminer. I did use Zadig to replace the driver, but perhaps it was still a driver issue?

Thanks again.

[yudismart]

thx for this info, i like this, couse i need.

[notlist3d]

Hi guys,

My apologies for the late reply. Some IRL familiy stuff happened.

I see now that I forgot to mention that I was running cgminer and bfgminer on Windows 10.

The unit did not come with a PSU. Perhaps the previous owner kept it. At first I attempted several PC PSU's that I had lying around (CoolerMaster, Corsair, Antec varying between 400W and 850W), but had no luck with those.

Ultimately, I lend the U3 to a friend for a couple of days and he had no trouble getting it to run on Debian. He returned the unit last weekend and I had some time today to tinker with it some more. I bought a Pi2 and a 120W PSU, just now installed Raspbian and I got running within 20 minutes using cgminer.

I'm happy that it runs, but I still have no clue where I went wrong with the Windows versions of cgminer and bfgminer. I did use Zadig to replace the driver, but perhaps it was still a driver issue?

Thanks again.

It's hard to say some they load zadig once... and no issues works great.  Others it's one of the most painful driver installs they will have.   

I think you will be much happier with the RPI then you were on windows.   It is also a low power controller which is great.   I think long term you made a good decision.  As you can always use the RPI for tons of projects one day after done mining with it.