[ANN] Technobit HEX8A1 -240 GHs Coincraft A1 board- Finished production

[Buchi-88]

THX at all,

at time the miner runs perfect on this:

"hexminer8-chip-mask" : "255",
"hexminer8-voltage"  : "860",
"hexminer8-options" : "8:230",

so a other question to make the miner quieter

Have the HEX temp sensors or is the air flow @ 5 or 7 V enough around 220GH/s?

I think 7V is enough and better than 5V!?

regards

[2GOOD]

THX at all,

at time the miner runs perfect on this:

"hexminer8-chip-mask" : "255",
"hexminer8-voltage"  : "860",
"hexminer8-options" : "8:230",

so a other question to make the miner quieter

Have the HEX temp sensors or is the air flow @ 5 or 7 V enough around 220GH/s?

I think 7V is enough and better than 5V!?

regards

The original fan is very powerfull for 7V, you may damage your PSU, instead connect 5W resistor 10-15ohm in series with the fan.

You can also use a 120mm fan instead of the 92 but you have to make some modifications, and finally if you have 2 devices here's what I've done:




The stand is from an old CD-ROM

[Buchi-88]

THX for your answer,

at time the original fan hangs at 5V and it's to the original very noise.

By ~200 GH/s the cooler are not hot and at time i have 0,04% HW, so i think it's enough!?

regards

[Buchi-88]

Good day ,

I suddenly have the problem that the HEX8A1 makes no hashes ?

cgminer version 4.4.2 - Started: [2014-11-29 23:26:11]
--------------------------------------------------------------------------------
 (5s):0.000 (1m):0.000 (5m):0.000 (15m):0.000 (avg):0.000h/s
 A:0  R:0  HW:0  WU:0.0/m
 Connected to miner-control.de diff 16 with stratum as user
 Block: d3fc8303...  Diff:1.19M  Started: [23:27:36]  Best share: 0
--------------------------------------------------------------------------------
 SB management [P]ool management Settings Display options Quit
 0: HEX8 0  : 220  850/ 800mV  |  0.000 /  0.000h/s WU:0.0/m
--------------------------------------------------------------------------------
 [2014-11-29 23:26:01] Started cgminer 4.4.2
 [2014-11-29 23:26:01] Loaded configuration file /home/pi/cgminerHEX.conf
 [2014-11-29 23:26:10] Probing for an alive pool
 [2014-11-29 23:26:10] Pool 0 difficulty changed to 16
 [2014-11-29 23:26:11] Pool 1 difficulty changed to 16
 [2014-11-29 23:26:11] Network diff set to 1.2M
 [2014-11-29 23:26:16] API running in IP access mode on port 4029 (13)

regards

[marto74]

hi give me TW access
to look over it

[Buchi-88]

THX for your help, but after a Cgminer re-installation and a Kernel Update by the Pi the HEXminer already make Hashes

regards

[Buchi-88]

Soory to say but at time i have the self problem, with no hash!?

At the evening i will test with a second power supply

cgminer version 4.4.2 - Started: [2014-12-06 11:59:35]
--------------------------------------------------------------------------------
 (5s):0.000 (1m):168.9M (5m):3.229G (15m):2.438G (avg):3.443Gh/s
 A:784  R:0  HW:0  WU:49.1/m
 Connected to miner-control.de diff 16 with stratum as user
 Block: d970747b...  Diff:1.08M  Started: [12:14:40]  Best share: 863
--------------------------------------------------------------------------------
 USB management Pool management Settings Display options Quit
 4: HEX8 4  : 220  850/ 800mV  |  0.000 /  0.000h/s WU:  0.0/m
--------------------------------------------------------------------------------
 [2014-12-06 12:05:21] HEX8 0 failure, disabling!
 [2014-12-06 12:06:42] HEX8 1 failure, disabling!
 [2014-12-06 12:06:57] HEX8 2 failure, disabling!
 [2014-12-06 12:09:33] HEX8 3 failure, disabling!

[Zich]

Soory to say but at time i have the self problem, with no hash!?

At the evening i will test with a second power supply

cgminer version 4.4.2 - Started: [2014-12-06 11:59:35]
--------------------------------------------------------------------------------
 (5s):0.000 (1m):168.9M (5m):3.229G (15m):2.438G (avg):3.443Gh/s
 A:784  R:0  HW:0  WU:49.1/m
 Connected to miner-control.de diff 16 with stratum as user
 Block: d970747b...  Diff:1.08M  Started: [12:14:40]  Best share: 863
--------------------------------------------------------------------------------
 USB management Pool management Settings Display options Quit
 4: HEX8 4  : 220  850/ 800mV  |  0.000 /  0.000h/s WU:  0.0/m
--------------------------------------------------------------------------------
 [2014-12-06 12:05:21] HEX8 0 failure, disabling!
 [2014-12-06 12:06:42] HEX8 1 failure, disabling!
 [2014-12-06 12:06:57] HEX8 2 failure, disabling!
 [2014-12-06 12:09:33] HEX8 3 failure, disabling!

Seem like overheat. Is the fan ok? The fan should be run using 12V.

[Biffa]

Could also be that the pi just doesn't have enough grunt to run two copies of cgminer at the same time.

[Buchi-88]

@Zich

I think it's not a problem with the heat, the miner doesn't start??

The same problem with Hotplug:

cgminer version 4.4.2 - Started: [2014-12-07 14:17:00]
--------------------------------------------------------------------------------
 (5s):0.000 (1m):0.000 (5m):0.000 (15m):0.000 (avg):0.000h/s
 ST: 3  SS: 0  NB: 8  LW: 653  GF: 1  RF: 0
 Connected to miner-control.de diff 16 with stratum as user NTYNy7JWo1LyK9Z51ZxdcpsdzEpfT5C6VV
 Block: 2e05d06d...  Diff:1.01M  Started: [14:33:59]  Best share: 0
--------------------------------------------------------------------------------
 USB management Pool management Settings Display options Quit
 2: HEX8 2  : 220  850/ 800mV  | A:0 R:0/0.00% HW:0/0.00%
--------------------------------------------------------------------------------
 [2014-12-07 14:17:00] Pool 1 difficulty changed to 16
 [2014-12-07 14:17:00] Network diff set to 1.07M
 [2014-12-07 14:17:05] API running in IP access mode on port 4029 (11)
 [2014-12-07 14:19:59] Network diff set to 1.03M
 [2014-12-07 14:19:59] Stratum from pool 0 detected new block
 [2014-12-07 14:23:22] Network diff set to 1.02M
 [2014-12-07 14:23:22] Stratum from pool 0 detected new block
 [2014-12-07 14:23:36] Network diff set to 1.03M
 [2014-12-07 14:23:36] Stratum from pool 0 detected new block
 [2014-12-07 14:25:26] Network diff set to 1.05M
 [2014-12-07 14:25:26] Stratum from pool 0 detected new block
 [2014-12-07 14:26:08] Network diff set to 1.05M
 [2014-12-07 14:26:08] Stratum from pool 0 detected new block
 [2014-12-07 14:27:08] Stratum connection to pool 0 interrupted
 [2014-12-07 14:27:08] Pool 0 difficulty changed to 16
 [2014-12-07 14:30:03] Network diff set to 1.03M
 [2014-12-07 14:30:03] Stratum from pool 0 detected new block
 [2014-12-07 14:33:59] Network diff set to 1.01M
 [2014-12-07 14:33:59] Stratum from pool 0 detected new block
[2014-12-07 14:34:04] HEX8 0 failure, disabling!
 [2014-12-07 14:34:24] Hotplug: hexminer8 added HEX8 1
 [2014-12-07 14:34:37] HEX8 1 failure, disabling!
 [2014-12-07 14:34:50] Hotplug: hexminer8 added HEX8 2

@Biffa

I don't think so the same problem with one instance....

config:

"hexminer8-set-diff-to-one" : "0",
"hexminer8-chip-mask" : "255",
"hexminer8-voltage"  : "850",
"hexminer8-options" : "8:220",
"set_default_to_8" : true

All lights light on the miner, where can i search the defect? THX

regards

[Zich]

@Zich

I think it's not a problem with the heat, the miner doesn't start??

The same problem with Hotplug:

.....

Are you using any usb hub? Try to plug it directly to Rpi.
Did Rpi use same power source with miner?
Try to change the usb cable.
Clean the board from dirt then visual check the component.

[Buchi-88]

@Zich

I think it's not a problem with the heat, the miner doesn't start??

The same problem with Hotplug:

.....

Are you using any usb hub? Try to plug it directly to Rpi.
Did Rpi use same power source with miner?
Try to change the usb cable.
Clean the board from dirt then visual check the component.

THX for your answer,

i will test your suggestions, and where appropriate make photos

a time he hashte again today when hotplugin, but after another hotplugin the same...

regards

[2GOOD]

HEX8 needs atleast 860mV to start, if not try 866mV

[cryptonit]

is there any sweet spot at underclocking this hw or is it time to sort them out?
if there any answer please PM me so i dont miss it

i run them now 860 210

[Zich]

is there any sweet spot at underclocking this hw or is it time to sort them out?
if there any answer please PM me so i dont miss it

i run them now 860 210

Unfortunately, that's already the lowest setting.

[gcube1305]

Hi all,

I have a problem with an HEX8A1 board.

I have two HEX8A1 boards. I have change the fans since it was way too noisy, and i use a 220/920 setting. The two boards are linked to a TPlink router with openwrt ("OpenWrt Barrier Breaker r40295", i think it is a 0.3.0) through an USB hub. All (tplink and boards, hub is not externally powered) are powered with the same Corsair CX760.

This was working like a charm for the last 6 months. But since two days now, one of the board is not hashing anymore.

Everything looks fine, the board is seen by cgminer, when i plug/unplug it i can see the board disappearing/reappearing, but the hashrate is always 0. The second board is working and hashing. The led are the same on the two boards.

I have tried to plug only one board, i have tried 210/860, i have change the usb port, i have plug the faultly board directly to the TPlink, i have reset settings to 260/1000, but nothing worked.

I don't think it is a overheat problem, cause the fans are identicall on the two boards, and with those fans and settings the boards seems cooler than with the noisy sunon and 260/1000 settings (i can put my finger on the it for more than 10s ). Moreover, i have a very very low error rate, and i did not change anything on the configuration for the last 6 months (and the room is at 18°).

Any idea ?
How can i see if it is a overheat problem ?

[Zich]

Hi all,

I have a problem with an HEX8A1 board.

I have two HEX8A1 boards. I have change the fans since it was way too noisy, and i use a 220/920 setting. The two boards are linked to a TPlink router with openwrt ("OpenWrt Barrier Breaker r40295", i think it is a 0.3.0) through an USB hub. All (tplink and boards, hub is not externally powered) are powered with the same Corsair CX760.

This was working like a charm for the last 6 months. But since two days now, one of the board is not hashing anymore.

Everything looks fine, the board is seen by cgminer, when i plug/unplug it i can see the board disappearing/reappearing, but the hashrate is always 0. The second board is working and hashing. The led are the same on the two boards.

I have tried to plug only one board, i have tried 210/860, i have change the usb port, i have plug the faultly board directly to the TPlink, i have reset settings to 260/1000, but nothing worked.

I don't think it is a overheat problem, cause the fans are identicall on the two boards, and with those fans and settings the boards seems cooler than with the noisy sunon and 260/1000 settings (i can put my finger on the it for more than 10s ). Moreover, i have a very very low error rate, and i did not change anything on the configuration for the last 6 months (and the room is at 18°).

Any idea ?
How can i see if it is a overheat problem ?

Seem like hardware problem. Try to let the board cool down for few hours, check if there is any hardware burn mark. Then try again. Then please post cgminer api log.

[gcube1305]

Hi all,

I have a problem with an HEX8A1 board.

I have two HEX8A1 boards. I have change the fans since it was way too noisy, and i use a 220/920 setting. The two boards are linked to a TPlink router with openwrt ("OpenWrt Barrier Breaker r40295", i think it is a 0.3.0) through an USB hub. All (tplink and boards, hub is not externally powered) are powered with the same Corsair CX760.

This was working like a charm for the last 6 months. But since two days now, one of the board is not hashing anymore.

Everything looks fine, the board is seen by cgminer, when i plug/unplug it i can see the board disappearing/reappearing, but the hashrate is always 0. The second board is working and hashing. The led are the same on the two boards.

I have tried to plug only one board, i have tried 210/860, i have change the usb port, i have plug the faultly board directly to the TPlink, i have reset settings to 260/1000, but nothing worked.

I don't think it is a overheat problem, cause the fans are identicall on the two boards, and with those fans and settings the boards seems cooler than with the noisy sunon and 260/1000 settings (i can put my finger on the it for more than 10s ). Moreover, i have a very very low error rate, and i did not change anything on the configuration for the last 6 months (and the room is at 18°).

Any idea ?
How can i see if it is a overheat problem ?

Seem like hardware problem. Try to let the board cool down for few hours, check if there is any hardware burn mark. Then try again. Then please post cgminer api log.

I have unplug the board last night, and replug it this morning, without any result. The board is not hot at all. There is absolutely no burn mark on the board.

Here is the CGMiner API log (a few minutes after a restart of tplink) (for information, error rate is 0 because of tplink reboot; after many hours i have never seen error rate over 0.1%, most of the times it is between 0.01 and 0.08) :

Code:

[Firmware Version] => 20140328
cgminer: 4_1_0_afb9743
Reply was 'STATUS=S,When=1424607810,Code=70,Msg=CGMiner stats,Description=cgminer 4.2.1|STATS=0,ID=HEX80,Enabled=Y,Status=Alive,Elapsed=510,MHS 5s=262.5G,MHS av=238.2G,Hardware Errors=0,Hardware Errors%=0.0000,USB Read Errors=0,USB Write Errors=0,USB Reset Count=0,Last Share Time=1424607807,Chip Count=8,Frequency=220,Core Voltage=920,PIC Voltage Readings=930,Chip1 Nonces=34,Chip1 Engines=30,Chip1 Dupes=0,Chip2 Nonces=25,Chip2 Engines=32,Chip2 Dupes=0,Chip3 Nonces=25,Chip3 Engines=32,Chip3 Dupes=0,Chip4 Nonces=27,Chip4 Engines=32,Chip4 Dupes=0,Chip5 Nonces=25,Chip5 Engines=32,Chip5 Dupes=0,Chip6 Nonces=33,Chip6 Engines=32,Chip6 Dupes=0,Chip7 Nonces=26,Chip7 Engines=32,Chip7 Dupes=0,Chip8 Nonces=26,Chip8 Engines=32,Chip8 Dupes=0|STATS=1,ID=HEX81,Enabled=Y,Status=Alive,Elapsed=510,MHS 5s=0.000,MHS av=0.000,Hardware Errors=0,Hardware Errors%=0.0000,USB Read Errors=0,USB Write Errors=0,USB Reset Count=0,Last Share Time=0,Chip Count=8,Frequency=220,Core Voltage=920,PIC Voltage Readings=800,Chip1 Nonces=0,Chip1 Engines=0,Chip1 Dupes=0,Chip2 Nonces=0,Chip2 Engines=0,Chip2 Dupes=0,Chip3 Nonces=0,Chip3 Engines=0,Chip3 Dupes=0,Chip4 Nonces=0,Chip4 Engines=0,Chip4 Dupes=0,Chip5 Nonces=0,Chip5 Engines=0,Chip5 Dupes=0,Chip6 Nonces=0,Chip6 Engines=0,Chip6 Dupes=0,Chip7 Nonces=0,Chip7 Engines=0,Chip7 Dupes=0,Chip8 Nonces=0,Chip8 Engines=0,Chip8 Dupes=0|STATS=2,ID=POOL0,Elapsed=510,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=128.00000000,Min Diff=128.00000000,Max Diff=128.00000000,Min Diff Count=398,Max Diff Count=398,Times Sent=223,Bytes Sent=26248,Times Recv=246,Bytes Recv=30822,Net Bytes Sent=26248,Net Bytes Recv=30822|STATS=3,ID=POOL1,Elapsed=510,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=0.00000000,Min Diff=0.00000000,Max Diff=0.00000000,Min Diff Count=0,Max Diff Count=0,Times Sent=0,Bytes Sent=0,Times Recv=0,Bytes Recv=0,Net Bytes Sent=0,Net Bytes Recv=0|STATS=4,ID=POOL2,Elapsed=510,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=0.00000000,Min Diff=0.00000000,Max Diff=0.00000000,Min Diff Count=0,Max Diff Count=0,Times Sent=0,Bytes Sent=0,Times Recv=0,Bytes Recv=0,Net Bytes Sent=0,Net Bytes Recv=0|'
[STATUS] =>
(
   [STATUS] => S
   [When] => 1424607810
   [Code] => 70
   [Msg] => CGMiner stats
   [Description] => cgminer 4.2.1
)
[STATS0] =>
(
   [STATS] => 0
   [ID] => HEX80
   [Enabled] => Y
   [Status] => Alive
   [Elapsed] => 510
   [MHS 5s] => 262.5G
   [MHS av] => 238.2G
   [Hardware Errors] => 0
   [Hardware Errors%] => 0.0000
   [USB Read Errors] => 0
   [USB Write Errors] => 0
   [USB Reset Count] => 0
   [Last Share Time] => 1424607807
   [Chip Count] => 8
   [Frequency] => 220
   [Core Voltage] => 920
   [PIC Voltage Readings] => 930
   [Chip1 Nonces] => 34
   [Chip1 Engines] => 30
   [Chip1 Dupes] => 0
   [Chip2 Nonces] => 25
   [Chip2 Engines] => 32
   [Chip2 Dupes] => 0
   [Chip3 Nonces] => 25
   [Chip3 Engines] => 32
   [Chip3 Dupes] => 0
   [Chip4 Nonces] => 27
   [Chip4 Engines] => 32
   [Chip4 Dupes] => 0
   [Chip5 Nonces] => 25
   [Chip5 Engines] => 32
   [Chip5 Dupes] => 0
   [Chip6 Nonces] => 33
   [Chip6 Engines] => 32
   [Chip6 Dupes] => 0
   [Chip7 Nonces] => 26
   [Chip7 Engines] => 32
   [Chip7 Dupes] => 0
   [Chip8 Nonces] => 26
   [Chip8 Engines] => 32
   [Chip8 Dupes] => 0
)
[STATS1] =>
(
   [STATS] => 1
   [ID] => HEX81
   [Enabled] => Y
   [Status] => Alive
   [Elapsed] => 510
   [MHS 5s] => 0.000
   [MHS av] => 0.000
   [Hardware Errors] => 0
   [Hardware Errors%] => 0.0000
   [USB Read Errors] => 0
   [USB Write Errors] => 0
   [USB Reset Count] => 0
   [Last Share Time] => 0
   [Chip Count] => 8
   [Frequency] => 220
   [Core Voltage] => 920
   [PIC Voltage Readings] => 800
   [Chip1 Nonces] => 0
   [Chip1 Engines] => 0
   [Chip1 Dupes] => 0
   [Chip2 Nonces] => 0
   [Chip2 Engines] => 0
   [Chip2 Dupes] => 0
   [Chip3 Nonces] => 0
   [Chip3 Engines] => 0
   [Chip3 Dupes] => 0
   [Chip4 Nonces] => 0
   [Chip4 Engines] => 0
   [Chip4 Dupes] => 0
   [Chip5 Nonces] => 0
   [Chip5 Engines] => 0
   [Chip5 Dupes] => 0
   [Chip6 Nonces] => 0
   [Chip6 Engines] => 0
   [Chip6 Dupes] => 0
   [Chip7 Nonces] => 0
   [Chip7 Engines] => 0
   [Chip7 Dupes] => 0
   [Chip8 Nonces] => 0
   [Chip8 Engines] => 0
   [Chip8 Dupes] => 0
)
[STATS2] =>
(
   [STATS] => 2
   [ID] => POOL0
   [Elapsed] => 510
   [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] => 128.00000000
   [Min Diff] => 128.00000000
   [Max Diff] => 128.00000000
   [Min Diff Count] => 398
   [Max Diff Count] => 398
   [Times Sent] => 223
   [Bytes Sent] => 26248
   [Times Recv] => 246
   [Bytes Recv] => 30822
   [Net Bytes Sent] => 26248
   [Net Bytes Recv] => 30822
)
[STATS3] =>
(
   [STATS] => 3
   [ID] => POOL1
   [Elapsed] => 510
   [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] => 0.00000000
   [Min Diff] => 0.00000000
   [Max Diff] => 0.00000000
   [Min Diff Count] => 0
   [Max Diff Count] => 0
   [Times Sent] => 0
   [Bytes Sent] => 0
   [Times Recv] => 0
   [Bytes Recv] => 0
   [Net Bytes Sent] => 0
   [Net Bytes Recv] => 0
)
[STATS4] =>
(
   [STATS] => 4
   [ID] => POOL2
   [Elapsed] => 510
   [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] => 0.00000000
   [Min Diff] => 0.00000000
   [Max Diff] => 0.00000000
   [Min Diff Count] => 0
   [Max Diff Count] => 0
   [Times Sent] => 0
   [Bytes Sent] => 0
   [Times Recv] => 0
   [Bytes Recv] => 0
   [Net Bytes Sent] => 0
   [Net Bytes Recv] => 0
)

[/code]

[gcube1305]

Hi all,

I have a problem with an HEX8A1 board.

I have two HEX8A1 boards. I have change the fans since it was way too noisy, and i use a 220/920 setting. The two boards are linked to a TPlink router with openwrt ("OpenWrt Barrier Breaker r40295", i think it is a 0.3.0) through an USB hub. All (tplink and boards, hub is not externally powered) are powered with the same Corsair CX760.

This was working like a charm for the last 6 months. But since two days now, one of the board is not hashing anymore.

Everything looks fine, the board is seen by cgminer, when i plug/unplug it i can see the board disappearing/reappearing, but the hashrate is always 0. The second board is working and hashing. The led are the same on the two boards.

I have tried to plug only one board, i have tried 210/860, i have change the usb port, i have plug the faultly board directly to the TPlink, i have reset settings to 260/1000, but nothing worked.

I don't think it is a overheat problem, cause the fans are identicall on the two boards, and with those fans and settings the boards seems cooler than with the noisy sunon and 260/1000 settings (i can put my finger on the it for more than 10s ). Moreover, i have a very very low error rate, and i did not change anything on the configuration for the last 6 months (and the room is at 18°).

Any idea ?
How can i see if it is a overheat problem ?

Seem like hardware problem. Try to let the board cool down for few hours, check if there is any hardware burn mark. Then try again. Then please post cgminer api log.

I have unplug the board last night, and replug it this morning, without any result. The board is not hot at all. There is absolutely no burn mark on the board.

Here is the CGMiner API log (a few minutes after a restart of tplink) (for information, error rate is 0 because of tplink reboot; after many hours i have never seen error rate over 0.1%, most of the times it is between 0.01 and 0.08) :

Code:

[Firmware Version] => 20140328
cgminer: 4_1_0_afb9743
Reply was 'STATUS=S,When=1424607810,Code=70,Msg=CGMiner stats,Description=cgminer 4.2.1|STATS=0,ID=HEX80,Enabled=Y,Status=Alive,Elapsed=510,MHS 5s=262.5G,MHS av=238.2G,Hardware Errors=0,Hardware Errors%=0.0000,USB Read Errors=0,USB Write Errors=0,USB Reset Count=0,Last Share Time=1424607807,Chip Count=8,Frequency=220,Core Voltage=920,PIC Voltage Readings=930,Chip1 Nonces=34,Chip1 Engines=30,Chip1 Dupes=0,Chip2 Nonces=25,Chip2 Engines=32,Chip2 Dupes=0,Chip3 Nonces=25,Chip3 Engines=32,Chip3 Dupes=0,Chip4 Nonces=27,Chip4 Engines=32,Chip4 Dupes=0,Chip5 Nonces=25,Chip5 Engines=32,Chip5 Dupes=0,Chip6 Nonces=33,Chip6 Engines=32,Chip6 Dupes=0,Chip7 Nonces=26,Chip7 Engines=32,Chip7 Dupes=0,Chip8 Nonces=26,Chip8 Engines=32,Chip8 Dupes=0|STATS=1,ID=HEX81,Enabled=Y,Status=Alive,Elapsed=510,MHS 5s=0.000,MHS av=0.000,Hardware Errors=0,Hardware Errors%=0.0000,USB Read Errors=0,USB Write Errors=0,USB Reset Count=0,Last Share Time=0,Chip Count=8,Frequency=220,Core Voltage=920,PIC Voltage Readings=800,Chip1 Nonces=0,Chip1 Engines=0,Chip1 Dupes=0,Chip2 Nonces=0,Chip2 Engines=0,Chip2 Dupes=0,Chip3 Nonces=0,Chip3 Engines=0,Chip3 Dupes=0,Chip4 Nonces=0,Chip4 Engines=0,Chip4 Dupes=0,Chip5 Nonces=0,Chip5 Engines=0,Chip5 Dupes=0,Chip6 Nonces=0,Chip6 Engines=0,Chip6 Dupes=0,Chip7 Nonces=0,Chip7 Engines=0,Chip7 Dupes=0,Chip8 Nonces=0,Chip8 Engines=0,Chip8 Dupes=0|STATS=2,ID=POOL0,Elapsed=510,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=128.00000000,Min Diff=128.00000000,Max Diff=128.00000000,Min Diff Count=398,Max Diff Count=398,Times Sent=223,Bytes Sent=26248,Times Recv=246,Bytes Recv=30822,Net Bytes Sent=26248,Net Bytes Recv=30822|STATS=3,ID=POOL1,Elapsed=510,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=0.00000000,Min Diff=0.00000000,Max Diff=0.00000000,Min Diff Count=0,Max Diff Count=0,Times Sent=0,Bytes Sent=0,Times Recv=0,Bytes Recv=0,Net Bytes Sent=0,Net Bytes Recv=0|STATS=4,ID=POOL2,Elapsed=510,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=0.00000000,Min Diff=0.00000000,Max Diff=0.00000000,Min Diff Count=0,Max Diff Count=0,Times Sent=0,Bytes Sent=0,Times Recv=0,Bytes Recv=0,Net Bytes Sent=0,Net Bytes Recv=0|'
[STATUS] =>
(
   [STATUS] => S
   [When] => 1424607810
   [Code] => 70
   [Msg] => CGMiner stats
   [Description] => cgminer 4.2.1
)
[STATS0] =>
(
   [STATS] => 0
   [ID] => HEX80
   [Enabled] => Y
   [Status] => Alive
   [Elapsed] => 510
   [MHS 5s] => 262.5G
   [MHS av] => 238.2G
   [Hardware Errors] => 0
   [Hardware Errors%] => 0.0000
   [USB Read Errors] => 0
   [USB Write Errors] => 0
   [USB Reset Count] => 0
   [Last Share Time] => 1424607807
   [Chip Count] => 8
   [Frequency] => 220
   [Core Voltage] => 920
   [PIC Voltage Readings] => 930
   [Chip1 Nonces] => 34
   [Chip1 Engines] => 30
   [Chip1 Dupes] => 0
   [Chip2 Nonces] => 25
   [Chip2 Engines] => 32
   [Chip2 Dupes] => 0
   [Chip3 Nonces] => 25
   [Chip3 Engines] => 32
   [Chip3 Dupes] => 0
   [Chip4 Nonces] => 27
   [Chip4 Engines] => 32
   [Chip4 Dupes] => 0
   [Chip5 Nonces] => 25
   [Chip5 Engines] => 32
   [Chip5 Dupes] => 0
   [Chip6 Nonces] => 33
   [Chip6 Engines] => 32
   [Chip6 Dupes] => 0
   [Chip7 Nonces] => 26
   [Chip7 Engines] => 32
   [Chip7 Dupes] => 0
   [Chip8 Nonces] => 26
   [Chip8 Engines] => 32
   [Chip8 Dupes] => 0
)
[STATS1] =>
(
   [STATS] => 1
   [ID] => HEX81
   [Enabled] => Y
   [Status] => Alive
   [Elapsed] => 510
   [MHS 5s] => 0.000
   [MHS av] => 0.000
   [Hardware Errors] => 0
   [Hardware Errors%] => 0.0000
   [USB Read Errors] => 0
   [USB Write Errors] => 0
   [USB Reset Count] => 0
   [Last Share Time] => 0
   [Chip Count] => 8
   [Frequency] => 220
   [Core Voltage] => 920
   [PIC Voltage Readings] => 800
   [Chip1 Nonces] => 0
   [Chip1 Engines] => 0
   [Chip1 Dupes] => 0
   [Chip2 Nonces] => 0
   [Chip2 Engines] => 0
   [Chip2 Dupes] => 0
   [Chip3 Nonces] => 0
   [Chip3 Engines] => 0
   [Chip3 Dupes] => 0
   [Chip4 Nonces] => 0
   [Chip4 Engines] => 0
   [Chip4 Dupes] => 0
   [Chip5 Nonces] => 0
   [Chip5 Engines] => 0
   [Chip5 Dupes] => 0
   [Chip6 Nonces] => 0
   [Chip6 Engines] => 0
   [Chip6 Dupes] => 0
   [Chip7 Nonces] => 0
   [Chip7 Engines] => 0
   [Chip7 Dupes] => 0
   [Chip8 Nonces] => 0
   [Chip8 Engines] => 0
   [Chip8 Dupes] => 0
)
[STATS2] =>
(
   [STATS] => 2
   [ID] => POOL0
   [Elapsed] => 510
   [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] => 128.00000000
   [Min Diff] => 128.00000000
   [Max Diff] => 128.00000000
   [Min Diff Count] => 398
   [Max Diff Count] => 398
   [Times Sent] => 223
   [Bytes Sent] => 26248
   [Times Recv] => 246
   [Bytes Recv] => 30822
   [Net Bytes Sent] => 26248
   [Net Bytes Recv] => 30822
)
[STATS3] =>
(
   [STATS] => 3
   [ID] => POOL1
   [Elapsed] => 510
   [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] => 0.00000000
   [Min Diff] => 0.00000000
   [Max Diff] => 0.00000000
   [Min Diff Count] => 0
   [Max Diff Count] => 0
   [Times Sent] => 0
   [Bytes Sent] => 0
   [Times Recv] => 0
   [Bytes Recv] => 0
   [Net Bytes Sent] => 0
   [Net Bytes Recv] => 0
)
[STATS4] =>
(
   [STATS] => 4
   [ID] => POOL2
   [Elapsed] => 510
   [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] => 0.00000000
   [Min Diff] => 0.00000000
   [Max Diff] => 0.00000000
   [Min Diff Count] => 0
   [Max Diff Count] => 0
   [Times Sent] => 0
   [Bytes Sent] => 0
   [Times Recv] => 0
   [Bytes Recv] => 0
   [Net Bytes Sent] => 0
   [Net Bytes Recv] => 0
)

[/code]

What is strange to me is the PICVoltage that is always 800 for the faulty board (i can see this with putty and cgminer output too ...). This let me think of a power problem, this is why i have tried with only the faulty board, without any success.

[loshia]

The voltage is read through usb when nonce comes
As long as board is not hashing nonces get recived va usb.it will stay constant...that is the answer.