What frequency are you running them at?  If I recall correctly 800 MHz is default. Also have to keep it in powers of 2 on diff frequency. So maybe try 780 or less and see if it will stay alive.  Also I you have a raspi burn an image of minera onto sdcard hook blades to the pi.  Then you have full mining solution. I have found that my 24mhs gridtowers run best with cpuminer with scrypt support

Br