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.

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.