gridseed miners mine for like 30 seconds sometimes and say "dead"

[thallium]

I"m trying to get 4 gridseed miner to run together. I'm using a raspberry pi with bfgminer as the software. Here is the weird thing. If i take 2 miners and hook the usb chord from the miner directly to the raspberry pi, i can get 2 miners running. the bfgminer program detects the miners and i'm hashing away with 2 miners.

when i try to get 4 miners running together through the powered usb hub (sabrent 13 port usb powered hub) is when i have trouble. bfg miner will sometimes detect all 4 miners and it's starts to mine, but never gets up to full hashing. then the hashing starts to die off and i get a "dead" status after about a minute

other times i can't even get it to detect the 4 miners at all.  If i skip the usb2.0 hub, then i can get 2 miners to run directly into the raspberry pi.

i believe the usb hub is compatible becuase i bought it from gaw miners.  

Here is my scrypt i run at the command line inside the bfgminer directory.

screen ./bfgminer -S gridseed:all --set-device gridseed:clock=850 --failover-only --scrypt -o stratum+tcp://dogus.nut2pools.com:5585 -u thallium1.thallium5 -p x

Anybody have an suggestions what i might be doing wrong? Any help would be apreciated. Thanks, Thal




Update: I'm thinking it might be the powered usb hub. I tried plugging the usb hub directly to my computer instead of the raspberry pi and my computer does not recognize the usb hub. So i think it might be that. What do you guys think? Did i answer my own question?


If i buy a new powered 2.0 hub, what would you guys recommend for the raspberry pi? 7 to 10 ports would be nice, i'd like to add more gridseed later once i get these 4 running.

[ab1jx]

Old thread, I know.  I assume you're talking about the little round Gridseed 5 chip miners that are USB powered.  The problem is that the combination of several of them draws more power than the USB hub provides.  You can get away with 1 or maybe 2, after that you have trouble.  It's a common problem with plugminers like Gekko's.  If you have some soldering and electronics skills you can beef up the 5 volt supply to the pins of each connector that need it.  Or these hubs have a good reputation of working well, since they claim to be able to deliver 70 watts.

  https://www.amazon.com/Superbpag-Portable-Charger-Transfer-Samsung/dp/B013OK10YM

It is a USB 3 hub but is known to work with a Raspberry Pi anyway.  Take a close look at the fine print on the wall wart or brick that powers the hub, it may not be supplying much over an amp total.  As you turn the clock rate up the ASICs draw more power, often over an amp each.  The USB 3 specs call for more current at each port, but Raspberry Pis don't like most USB 3 hubs.

My Gridseed is a G-Blade with 80 chips, it draws about 100 watts from a "real" power supply.  The USB connections are only for signal, not power, and it works fine.