I was able to bring chip number 3 back to life ! For all those who wondered, the board will work fine if one chip fails. Since the chip was working on arrival I refused Ztex's offer to send the board back for warranty. I was sad but it turned out that the mistake was on my side. It looks like I used a bit too much thermal grease at the wrong place. Somehow, the grease must have found a way to some components on the board or even the pins of the FPGA.
I removed the heatsink, cleaned the FPGA with ethanol and gave it a good spray of WD40. BAAAM, I'm back in business
New block detected by long polling
bus-0-0: ztex_ufm1_15d4-0001-02-05-1: f=204.00MHz, errorRate=0.00%, maxErrorRa
te=0.50%, hashRate=204.0MH/s, submitted 14 new nonces, luckFactor=0.99
bus-0-0: ztex_ufm1_15d4-0001-02-06-1: f=208.00MHz, errorRate=0.49%, maxErrorRa
te=1.41%, hashRate=207.0MH/s, submitted 10 new nonces, luckFactor=1.01
bus-0-0: ztex_ufm1_15y1-0001-02-07-1: f=212.00MHz, errorRate=0.18%, maxErrorRa
te=2.26%, hashRate=211.6MH/s, submitted 19 new nonces, luckFactor=0.96
bus-0-0: ztex_ufm1_15y1-0001-02-07-2: f=204.00MHz, errorRate=0.00%, maxErrorRa
te=0.00%, hashRate=204.0MH/s, submitted 14 new nonces, luckFactor=1.03
bus-0-0: ztex_ufm1_15y1-0001-02-07-3: Error: Hash rate drop of 6.0% detect. This
may be caused by overheating. FPGA is shut down to prevent damage. 50.0: Devic
e disabled since 2012-05-05T19:04:40
bus-0-0: ztex_ufm1_15y1-0001-02-07-4: f=200.00MHz, errorRate=0.39%, maxErrorRa
te=0.91%, hashRate=199.2MH/s, submitted 15 new nonces, luckFactor=1.03
bus-0-0: poll loop time: 34ms (USB: 3ms network: 31ms) getwork time: 136ms su
bmit time: 218ms
Total hash rate: 1025.8 MH/s
Total submitted hash rate: 1025.5 MH/s
--------
(Re)Scanning bus ...
MAC address: 0004a32dccc0
ztex_ufm1_15d4-0001-02-05: New device: bitfile=ztex_ufm1_15d4 f_default=200.00
MHz f_max=240.00MHz HpC=1.0H
ztex_ufm1_15d4-0001-02-05: FPGA 1: configuration time: 336 ms
ztex_ufm1_15d4-0001-02-05-1: New FPGA
ztex_ufm1_15d4-0001-02-05-1: Set frequency to 200.00MHz
Starting mining thread for bus bus-0-0
bus-0-0: ztex_ufm1_15d4-0001-02-05-1: added
MAC address: 0004a32df1c1
ztex_ufm1_15d4-0001-02-06: New device: bitfile=ztex_ufm1_15d4 f_default=200.00
MHz f_max=240.00MHz HpC=1.0H
ztex_ufm1_15d4-0001-02-06: FPGA 1: configuration time: 337 ms
ztex_ufm1_15d4-0001-02-06-1: New FPGA
ztex_ufm1_15d4-0001-02-06-1: Set frequency to 200.00MHz
bus-0-0: ztex_ufm1_15d4-0001-02-06-1: added
MAC address: 0004a3462b87
ztex_ufm1_15y1-0001-02-07: New device: bitfile=ztex_ufm1_15y1 f_default=200.00
MHz f_max=240.00MHz HpC=1.0H
ztex_ufm1_15y1-0001-02-07: FPGA 1: configuration time: 320 ms
ztex_ufm1_15y1-0001-02-07: FPGA 2: configuration time: 317 ms
ztex_ufm1_15y1-0001-02-07: FPGA 3: configuration time: 317 ms
ztex_ufm1_15y1-0001-02-07: FPGA 4: configuration time: 318 ms
ztex_ufm1_15y1-0001-02-07-1: New FPGA
ztex_ufm1_15y1-0001-02-07-1: Set frequency to 200.00MHz
bus-0-0: ztex_ufm1_15y1-0001-02-07-1: added
ztex_ufm1_15y1-0001-02-07-2: New FPGA
ztex_ufm1_15y1-0001-02-07-2: Set frequency to 200.00MHz
bus-0-0: ztex_ufm1_15y1-0001-02-07-2: added
ztex_ufm1_15y1-0001-02-07-3: New FPGA
ztex_ufm1_15y1-0001-02-07-3: Set frequency to 200.00MHz
bus-0-0: ztex_ufm1_15y1-0001-02-07-3: added
ztex_ufm1_15y1-0001-02-07-4: New FPGA
ztex_ufm1_15y1-0001-02-07-4: Set frequency to 200.00MHz
bus-0-0: ztex_ufm1_15y1-0001-02-07-4: added
3 new devices found.
Summary:
Bus bus-0-0 : 6 miners
Total : 6 miners
Disconnect all devices or enter `q' for exit. Enter `h' for help.
bus-0-0: ztex_ufm1_15y1-0001-02-07-4: Using LongPolling URL http://mint.bitminte
r.com:8332/lp
bus-0-0: ztex_ufm1_15d4-0001-02-05-1: f=200.00MHz, errorRate=0.00%, maxErrorRa
te=0.00%, hashRate=200.0MH/s, submitted 5 new nonces, luckFactor=1.79
bus-0-0: ztex_ufm1_15d4-0001-02-06-1: f=200.00MHz, errorRate=0.00%, maxErrorRa
te=0.00%, hashRate=200.0MH/s, submitted 5 new nonces, luckFactor=1.79
bus-0-0: ztex_ufm1_15y1-0001-02-07-1: f=200.00MHz, errorRate=0.00%, maxErrorRa
te=0.00%, hashRate=200.0MH/s, submitted 1 new nonces, luckFactor=0.36
bus-0-0: ztex_ufm1_15y1-0001-02-07-2: f=200.00MHz, errorRate=0.00%, maxErrorRa
te=0.00%, hashRate=200.0MH/s, submitted 0 new nonces, luckFactor=0.00
bus-0-0: ztex_ufm1_15y1-0001-02-07-3: f=200.00MHz, errorRate=0.00%, maxErrorRa
te=0.00%, hashRate=200.0MH/s, submitted 4 new nonces, luckFactor=1.44
bus-0-0: ztex_ufm1_15y1-0001-02-07-4: f=200.00MHz, errorRate=0.00%, maxErrorRa
te=0.00%, hashRate=200.0MH/s, submitted 3 new nonces, luckFactor=1.08
bus-0-0: poll loop time: 26ms (USB: 4ms network: 22ms) getwork time: 96ms sub
mit time: 101ms
Total hash rate: 1200.0 MH/s
Total submitted hash rate: 1288.3 MH/s
--------
bus-0-0: ztex_ufm1_15y1-0001-02-07-4: Set frequency to 204.00MHz
bus-0-0: ztex_ufm1_15y1-0001-02-07-2: Set frequency to 204.00MHz
bus-0-0: ztex_ufm1_15y1-0001-02-07-3: Set frequency to 204.00MHz
bus-0-0: ztex_ufm1_15d4-0001-02-05-1: Set frequency to 204.00MHz
bus-0-0: ztex_ufm1_15d4-0001-02-06-1: Set frequency to 204.00MHz
bus-0-0: ztex_ufm1_15y1-0001-02-07-1: Set frequency to 204.00MHz
bus-0-0: ztex_ufm1_15y1-0001-02-07-2: Set frequency to 208.00MHz
bus-0-0: ztex_ufm1_15y1-0001-02-07-3: Set frequency to 208.00MHz
bus-0-0: ztex_ufm1_15y1-0001-02-07-4: Set frequency to 208.00MHz
bus-0-0: ztex_ufm1_15y1-0001-02-07-1: Set frequency to 208.00MHz
bus-0-0: ztex_ufm1_15d4-0001-02-05-1: Set frequency to 208.00MHz
bus-0-0: ztex_ufm1_15d4-0001-02-06-1: Set frequency to 208.00MHz
bus-0-0: ztex_ufm1_15y1-0001-02-07-4: Set frequency to 204.00MHz
bus-0-0: ztex_ufm1_15y1-0001-02-07-2: Set frequency to 212.00MHz
bus-0-0: ztex_ufm1_15y1-0001-02-07-3: Set frequency to 212.00MHz
bus-0-0: ztex_ufm1_15y1-0001-02-07-1: Set frequency to 212.00MHz
bus-0-0: ztex_ufm1_15d4-0001-02-06-1: Set frequency to 212.00MHz
bus-0-0: ztex_ufm1_15d4-0001-02-05-1: Set frequency to 212.00MHz
bus-0-0: ztex_ufm1_15d4-0001-02-05-1: Set frequency to 208.00MHz
bus-0-0: ztex_ufm1_15y1-0001-02-07-2: Set frequency to 208.00MHz
bus-0-0: ztex_ufm1_15d4-0001-02-06-1: Set frequency to 208.00MHz
bus-0-0: ztex_ufm1_15d4-0001-02-06-1: Set frequency to 212.00MHz
bus-0-0: ztex_ufm1_15y1-0001-02-07-3: Set frequency to 216.00MHz
bus-0-0: ztex_ufm1_15y1-0001-02-07-1: Set frequency to 216.00MHz
bus-0-0: ztex_ufm1_15y1-0001-02-07-3: Set frequency to 212.00MHz
bus-0-0: ztex_ufm1_15d4-0001-02-06-1: Set frequency to 208.00MHz
bus-0-0: ztex_ufm1_15y1-0001-02-07-3: Set frequency to 216.00MHz
bus-0-0: ztex_ufm1_15y1-0001-02-07-1: Set frequency to 212.00MHz
bus-0-0: ztex_ufm1_15y1-0001-02-07-3: Set frequency to 212.00MHz
bus-0-0: ztex_ufm1_15d4-0001-02-05-1: f=208.00MHz, errorRate=0.79%, maxErrorRa
te=0.95%, hashRate=206.4MH/s, submitted 8 new nonces, luckFactor=0.76
bus-0-0: ztex_ufm1_15d4-0001-02-06-1: f=208.00MHz, errorRate=0.35%, maxErrorRa
te=1.10%, hashRate=207.3MH/s, submitted 14 new nonces, luckFactor=1.10
bus-0-0: ztex_ufm1_15y1-0001-02-07-1: f=212.00MHz, errorRate=0.00%, maxErrorRa
te=0.00%, hashRate=212.0MH/s, submitted 11 new nonces, luckFactor=0.68
bus-0-0: ztex_ufm1_15y1-0001-02-07-2: f=208.00MHz, errorRate=0.77%, maxErrorRa
te=1.05%, hashRate=206.4MH/s, submitted 16 new nonces, luckFactor=0.93
bus-0-0: ztex_ufm1_15y1-0001-02-07-3: f=212.00MHz, errorRate=0.67%, maxErrorRa
te=1.70%, hashRate=210.6MH/s, submitted 14 new nonces, luckFactor=1.02
bus-0-0: ztex_ufm1_15y1-0001-02-07-4: f=204.00MHz, errorRate=0.93%, maxErrorRa
te=1.56%, hashRate=202.1MH/s, submitted 11 new nonces, luckFactor=0.83
bus-0-0: poll loop time: 26ms (USB: 5ms network: 21ms) getwork time: 94ms sub
mit time: 115ms
Total hash rate: 1244.7 MH/s
Total submitted hash rate: 1097.5 MH/s
--------
bus-0-0: ztex_ufm1_15y1-0001-02-07-3: Set frequency to 208.00MHz
bus-0-0: ztex_ufm1_15d4-0001-02-05-1: Set frequency to 212.00MHz
bus-0-0: ztex_ufm1_15d4-0001-02-05-1: Set frequency to 208.00MHz
New block detected by long polling
bus-0-0: ztex_ufm1_15d4-0001-02-05-1: f=208.00MHz, errorRate=0.14%, maxErrorRa
te=1.43%, hashRate=207.7MH/s, submitted 11 new nonces, luckFactor=0.76
bus-0-0: ztex_ufm1_15d4-0001-02-06-1: f=208.00MHz, errorRate=0.01%, maxErrorRa
te=1.10%, hashRate=208.0MH/s, submitted 9 new nonces, luckFactor=0.88
bus-0-0: ztex_ufm1_15y1-0001-02-07-1: f=212.00MHz, errorRate=0.07%, maxErrorRa
te=0.71%, hashRate=211.9MH/s, submitted 20 new nonces, luckFactor=0.99
bus-0-0: ztex_ufm1_15y1-0001-02-07-2: f=208.00MHz, errorRate=0.08%, maxErrorRa
te=1.05%, hashRate=207.8MH/s, submitted 10 new nonces, luckFactor=0.82
bus-0-0: ztex_ufm1_15y1-0001-02-07-3: f=208.00MHz, errorRate=0.00%, maxErrorRa
te=0.00%, hashRate=208.0MH/s, submitted 17 new nonces, luckFactor=1.10
bus-0-0: ztex_ufm1_15y1-0001-02-07-4: f=204.00MHz, errorRate=0.38%, maxErrorRa
te=1.56%, hashRate=203.2MH/s, submitted 14 new nonces, luckFactor=0.90
bus-0-0: poll loop time: 25ms (USB: 5ms network: 20ms) getwork time: 93ms sub
mit time: 107ms
Total hash rate: 1246.6 MH/s
Total submitted hash rate: 1125.7 MH/s
--------
New block detected by long polling
bus-0-0: ztex_ufm1_15y1-0001-02-07-2: Set frequency to 212.00MHz
bus-0-0: ztex_ufm1_15y1-0001-02-07-2: Set frequency to 208.00MHz
bus-0-0: ztex_ufm1_15d4-0001-02-05-1: f=208.00MHz, errorRate=0.28%, maxErrorRa
te=1.43%, hashRate=207.4MH/s, submitted 21 new nonces, luckFactor=0.98
bus-0-0: ztex_ufm1_15d4-0001-02-06-1: f=208.00MHz, errorRate=0.06%, maxErrorRa
te=1.10%, hashRate=207.9MH/s, submitted 19 new nonces, luckFactor=1.02
bus-0-0: ztex_ufm1_15y1-0001-02-07-1: f=212.00MHz, errorRate=0.22%, maxErrorRa
te=0.71%, hashRate=211.5MH/s, submitted 9 new nonces, luckFactor=0.87
bus-0-0: ztex_ufm1_15y1-0001-02-07-2: f=208.00MHz, errorRate=0.76%, maxErrorRa
te=1.71%, hashRate=206.4MH/s, submitted 5 new nonces, luckFactor=0.68
bus-0-0: ztex_ufm1_15y1-0001-02-07-3: f=208.00MHz, errorRate=0.00%, maxErrorRa
te=0.00%, hashRate=208.0MH/s, submitted 17 new nonces, luckFactor=1.12
bus-0-0: ztex_ufm1_15y1-0001-02-07-4: f=204.00MHz, errorRate=1.58%, maxErrorRa
te=1.93%, hashRate=200.8MH/s, submitted 19 new nonces, luckFactor=1.05
bus-0-0: poll loop time: 25ms (USB: 4ms network: 20ms) getwork time: 94ms sub
mit time: 104ms
Total hash rate: 1242.0 MH/s
Total submitted hash rate: 1176.5 MH/s
--------
bus-0-0: ztex_ufm1_15y1-0001-02-07-1: Set frequency to 216.00MHz
bus-0-0: ztex_ufm1_15y1-0001-02-07-1: Set frequency to 212.00MHz
bus-0-0: ztex_ufm1_15y1-0001-02-07-3: Set frequency to 216.00MHz
bus-0-0: ztex_ufm1_15y1-0001-02-07-3: Set frequency to 212.00MHz
bus-0-0: ztex_ufm1_15d4-0001-02-05-1: f=208.00MHz, errorRate=0.16%, maxErrorRa
te=1.43%, hashRate=207.7MH/s, submitted 16 new nonces, luckFactor=1.01
bus-0-0: ztex_ufm1_15d4-0001-02-06-1: f=208.00MHz, errorRate=0.01%, maxErrorRa
te=1.10%, hashRate=208.0MH/s, submitted 12 new nonces, luckFactor=0.97
bus-0-0: ztex_ufm1_15y1-0001-02-07-1: f=212.00MHz, errorRate=0.51%, maxErrorRa
te=1.13%, hashRate=210.9MH/s, submitted 15 new nonces, luckFactor=0.91
bus-0-0: ztex_ufm1_15y1-0001-02-07-2: f=208.00MHz, errorRate=0.02%, maxErrorRa
te=1.71%, hashRate=208.0MH/s, submitted 19 new nonces, luckFactor=0.82
bus-0-0: ztex_ufm1_15y1-0001-02-07-3: f=212.00MHz, errorRate=2.22%, maxErrorRa
te=2.22%, hashRate=207.3MH/s, submitted 17 new nonces, luckFactor=1.14
bus-0-0: ztex_ufm1_15y1-0001-02-07-4: f=204.00MHz, errorRate=1.55%, maxErrorRa
te=1.93%, hashRate=200.8MH/s, submitted 12 new nonces, luckFactor=1.01
bus-0-0: poll loop time: 25ms (USB: 4ms network: 20ms) getwork time: 91ms sub
mit time: 104ms
Total hash rate: 1242.6 MH/s
Total submitted hash rate: 1206.5 MH/s