Full diagnostic outputs to much information when board drops occurs once in a while.
I did found a error on cs3 and short after a reinit of that board.
Also it looks like it stalls the other boards as well but this might be normal as nonces display

[2016-11-30 22:11:57] Negative nonce_processed
[2016-11-30 22:11:58] BA22: invalid nonce - HW error
[2016-11-30 22:11:58] chip(cs3) 13: invalid nonce 0x5496af07
[2016-11-30 22:11:58] Negative nonce_processed
[2016-11-30 22:11:59] Job is not working from chip(cs2) 0 <-- boards stall because off board cs3 ??
[2016-11-30 22:11:59] Job is not working from chip(cs2) 1
[2016-11-30 22:11:59] Job is not working from chip(cs2) 2
[2016-11-30 22:11:59] Job is not working from chip(cs2) 4
[2016-11-30 22:11:59] Job is not working from chip(cs2) 5
[2016-11-30 22:11:59] Job is not working from chip(cs2) 7
[2016-11-30 22:11:59] Job is not working from chip(cs2) 8
[2016-11-30 22:11:59] Job is not working from chip(cs2) 9
[2016-11-30 22:11:59] Job is not working from chip(cs2) 10
[2016-11-30 22:11:59] Job is not working from chip(cs2) 12
[2016-11-30 22:11:59] Job is not working from chip(cs2) 13
[2016-11-30 22:11:59] Job is not working from chip(cs2) 14
[2016-11-30 22:11:59] Job is not working from chip(cs2) 15
[2016-11-30 22:11:59] Job is not working from chip(cs2) 16
[2016-11-30 22:11:59] Job is not working from chip(cs2) 17
[2016-11-30 22:12:00] Job is not working from chip(cs2) 18
[2016-11-30 22:12:00] Job is not working from chip(cs2) 19
[2016-11-30 22:12:00] nonces processed 20
[2016-11-30 22:12:00] nonces processed 5
[2016-11-30 22:12:00] Submitting share 9d73b322 to pool 0
[2016-11-30 22:12:00] Accepted 9d73b322 Diff 107K/16384 BA2 0 pool 0
[2016-11-30 22:12:00] Accepted 9d73b322 Diff 107K/16384 BA2 0
[2016-11-30 22:12:00] Job is not working from chip(cs3) 6
[2016-11-30 22:12:00] Job is not working from chip(cs3) 8
[2016-11-30 22:12:00] Job is not working from chip(cs3) 10
[2016-11-30 22:12:00] Job is not working from chip(cs3) 14
[2016-11-30 22:12:00] Job is not working from chip(cs3) 15
[2016-11-30 22:12:00] Job is not working from chip(cs3) 18
[2016-11-30 22:12:00] Reinit board (cs3)
[2016-11-30 22:12:00] spidev0.0(cs3): Found 20 A2 chips
[2016-11-30 22:12:00] Found chip 1 with 100 active cores
[2016-11-30 22:12:00] Found chip 2 with 100 active cores
[2016-11-30 22:12:00] Found chip 3 with 100 active cores
[2016-11-30 22:12:00] Found chip 4 with 100 active cores
[2016-11-30 22:12:00] Found chip 5 with 100 active cores
[2016-11-30 22:12:00] Found chip 6 with 100 active cores
[2016-11-30 22:12:00] Found chip 7 with 100 active cores
[2016-11-30 22:12:00] Found chip 8 with 100 active cores
[2016-11-30 22:12:00] Found chip 9 with 100 active cores
[2016-11-30 22:12:00] Found chip 10 with 100 active cores
[2016-11-30 22:12:00] Found chip 11 with 100 active cores
[2016-11-30 22:12:00] Found chip 12 with 100 active cores
[2016-11-30 22:12:00] Found chip 13 with 100 active cores
[2016-11-30 22:12:00] Found chip 14 with 100 active cores
[2016-11-30 22:12:00] Found chip 15 with 100 active cores
[2016-11-30 22:12:00] Found chip 16 with 100 active cores
[2016-11-30 22:12:00] Found chip 17 with 100 active cores
[2016-11-30 22:12:00] Found chip 18 with 100 active cores
[2016-11-30 22:12:00] Found chip 19 with 100 active cores
[2016-11-30 22:12:00] Found chip 20 with 100 active cores
[2016-11-30 22:12:00] Found 20 chips with total 2000 active cores
[2016-11-30 22:12:00] Job is not working from chip(cs1) 0
[2016-11-30 22:12:00] Job is not working from chip(cs1) 1
[2016-11-30 22:12:00] Job is not working from chip(cs1) 2
[2016-11-30 22:12:00] Job is not working from chip(cs1) 3
[2016-11-30 22:12:00] Job is not working from chip(cs1) 5
[2016-11-30 22:12:00] Job is not working from chip(cs1) 6
[2016-11-30 22:12:00] Job is not working from chip(cs1) 7
[2016-11-30 22:12:00] Job is not working from chip(cs1) 9
[2016-11-30 22:12:00] Job is not working from chip(cs1) 10
[2016-11-30 22:12:00] Job is not working from chip(cs1) 11
[2016-11-30 22:12:00] Job is not working from chip(cs1) 12
[2016-11-30 22:12:00] Job is not working from chip(cs1) 13
[2016-11-30 22:12:00] Job is not working from chip(cs1) 14
[2016-11-30 22:12:00] Job is not working from chip(cs1) 15
[2016-11-30 22:12:00] Job is not working from chip(cs1) 17
[2016-11-30 22:12:00] Job is not working from chip(cs1) 18
[2016-11-30 22:12:00] nonces processed 20
[2016-11-30 22:12:00] Job is not working from chip(cs4) 0
[2016-11-30 22:12:00] Job is not working from chip(cs4) 1
[2016-11-30 22:12:00] Job is not working from chip(cs4) 2
[2016-11-30 22:12:00] Job is not working from chip(cs4) 3
[2016-11-30 22:12:00] Job is not working from chip(cs4) 4
[2016-11-30 22:12:00] Job is not working from chip(cs4) 5
[2016-11-30 22:12:00] Job is not working from chip(cs4) 6
[2016-11-30 22:12:00] Job is not working from chip(cs4) 7
[2016-11-30 22:12:00] Job is not working from chip(cs4) 8
[2016-11-30 22:12:00] Job is not working from chip(cs4) 9
[2016-11-30 22:12:00] Job is not working from chip(cs4) 10
[2016-11-30 22:12:00] Job is not working from chip(cs4) 11
[2016-11-30 22:12:00] Job is not working from chip(cs4) 12
[2016-11-30 22:12:00] Job is not working from chip(cs4) 13
[2016-11-30 22:12:00] Job is not working from chip(cs4) 14
[2016-11-30 22:12:00] Job is not working from chip(cs4) 16
[2016-11-30 22:12:00] Job is not working from chip(cs4) 17
[2016-11-30 22:12:00] Job is not working from chip(cs4) 18
[2016-11-30 22:12:00] Job is not working from chip(cs4) 19
[2016-11-30 22:12:00] nonces processed 20
BA21 cs:2 A:20 -C:20 (10-10-10-10-10-10-10-10-10-10-10-10-10-10-10-1(5s):68.13M (avg):69.03Mh/s | A:350208 R:0 HBA20 cs:1 A:20 -C:20 (10-10-10-10-10-10-10-10-10-10-10-10-10-10-10-1(5s):68.29M (avg):69.11Mh/s | A:274432 R:0 H [2016-11-30 22:12:01] Submitting share e677d523 to pool 0 -0
[2016-11-30 22:12:01] Accepted 02e677d5 Diff 22.6K/16384 BA2 1 pool 0
[2016-11-30 22:12:01] Accepted 02e677d5 Diff 22.6K/16384 BA2 1
BA23 cs:4 A:20 -C:20 (10-10-10-10-10-10-10-10-10-10-10-10-10-10-10-1(5s):68.00M (avg):67.83Mh/s | A:313856 R:0 HBA22 cs:3 A:20 -C:20 (10-10-10-10-10-10-10-10-10-10-10-10-10-10-10-1(5s):65.22M (avg):67.94Mh/s | A:263680 R:0 H [2016-11-30 22:12:02] BA22: invalid nonce - HW error 00-00-0
[2016-11-30 22:12:02] chip(cs3) 18: invalid nonce 0x6f9f1000