If he can provide the CGminer API Log it will be easy to narrow down. The Btmine rigs have been a nightmare, the build quality is extremely poor. Of the five I own, I have already rebuilt 4 and working on the 5th one.
Mtnminer
power supply or internet connection
The api log :
[Firmware Version] => 20131110
cgminer: 176747f
cgminer-openwrt-packages: 0e12b1b
luci: 346e3e7
Reply was 'STATUS=S,When=1391458436,Code=70,Msg=CGMiner stats,Description=cgminer 3.4.3|STATS=0,ID=AVA0,Elapsed=11,Calls=0,Wait=0.000000,Max=0.000000,Min=99999999.000000,baud=115200,miner_count=16,asic_count=10,timeout=9,frequency=1300,fan1=0,fan2=0,fan3=0,temp1=0,temp2=0,temp3=0,temp_max=0,Device Hardware%=0.0000,no_matching_work=0,match_work_count1=0,match_work_count2=0,match_work_count3=0,match_work_count4=0,match_work_count5=0,match_work_count6=0,match_work_count7=0,match_work_count8=0,match_work_count9=0,match_work_count10=0,match_work_count11=0,match_work_count12=0,match_work_count13=0,match_work_count14=0,match_work_count15=0,match_work_count16=0,Controller Version=2013110865,Avalon Chip=55,USB Pipe=0,USB Delay=r0 0.000000 w0 0.000000,USB tmo=2128 0|STATS=1,ID=POOL0,Elapsed=11,Calls=0,Wait=0.000000,Max=0.000000,Min=99999999.000000,Pool Calls=0,Pool Attempts=0,Pool Wait=0.000000,Pool Max=0.000000,Pool Min=99999999.000000,Pool Av=0.000000,Work Had Roll Time=false,Work Can Roll=false,Work Had Expire=false,Work Roll Time=0,Work Diff=3.00000000,Min Diff=3.00000000,Max Diff=3.00000000,Min Diff Count=599,Max Diff Count=599,Times Sent=4,Bytes Sent=315,Times Recv=8,Bytes Recv=2952,Net Bytes Sent=1060,Net Bytes Recv=2952|'
[STATUS] =>
(
[STATUS] => S
[When] => 1391458436
=> 70
[Msg] => CGMiner stats
[Description] => cgminer 3.4.3
)
[STATS0] =>
(
[STATS] => 0
[ID] => AVA0
[Elapsed] => 11
[Calls] => 0
[Wait] => 0.000000
[Max] => 0.000000
[Min] => 99999999.000000
[baud] => 115200
[miner_count] => 16
[asic_count] => 10
[timeout] => 9
[frequency] => 1300
[fan1] => 0
[fan2] => 0
[fan3] => 0
[temp1] => 0
[temp2] => 0
[temp3] => 0
[temp_max] => 0
[Device Hardware%] => 0.0000
[no_matching_work] => 0
[match_work_count1] => 0
[match_work_count2] => 0
[match_work_count3] => 0
[match_work_count4] => 0
[match_work_count5] => 0
[match_work_count6] => 0
[match_work_count7] => 0
[match_work_count8] => 0
[match_work_count9] => 0
[match_work_count10] => 0
[match_work_count11] => 0
[match_work_count12] => 0
[match_work_count13] => 0
[match_work_count14] => 0
[match_work_count15] => 0
[match_work_count16] => 0
[Controller Version] => 2013110865
[Avalon Chip] => 55
[USB Pipe] => 0
[USB Delay] => r0 0.000000 w0 0.000000
[USB tmo] => 2128 0
)
[STATS1] =>
(
[STATS] => 1
[ID] => POOL0
[Elapsed] => 11
[Calls] => 0
[Wait] => 0.000000
[Max] => 0.000000
[Min] => 99999999.000000
[Pool Calls] => 0
[Pool Attempts] => 0
[Pool Wait] => 0.000000
[Pool Max] => 0.000000
[Pool Min] => 99999999.000000
[Pool Av] => 0.000000
[Work Had Roll Time] => false
[Work Can Roll] => false
[Work Had Expire] => false
[Work Roll Time] => 0
[Work Diff] => 3.00000000
[Min Diff] => 3.00000000
[Max Diff] => 3.00000000
[Min Diff Count] => 599
[Max Diff Count] => 599
[Times Sent] => 4
[Bytes Sent] => 315
[Times Recv] => 8
[Bytes Recv] => 2952
[Net Bytes Sent] => 1060
[Net Bytes Recv] => 2952
)