Bitfury 400G FIRE Hazard (pics)

[AMD FTW]

So I own a bunch of these 400G fully populated units and they've been hashing for the past 1.5 weeks roughly. Today I get a 15 minute  BTCGUILD idle miner notification. I go out to check on the unit and its just flashing a red light on the raspberry pi. So I'm thinking that's weird as all my other units are plugged into backup APC smart UPS units and they are all still hashing away. I'm thinking ok a dead raspberry pi or a bad SD card. I restart the unit and it boots up and then an arc of light and it shut down again. Now I'm thinking WTF that's not good. So that's when I noticed the melted wires on the XFX 850w unit. Right now all my 12 rigs are powered via separate 1250 xfx gold psu's except 2 units. My other 2 units are being powered by the XFX 850w Gold and also a corsair AX 850w Gold. All my psu's being used are not being overloaded as you can see and they are all top rated power supplies as I don't mess around with cheap equipment or inferior equipment. I also have my cards completely heatsinked to remove the excess heat and my ambient room temperature is 15C or about 60F. The ambient air next to the rigs is 21C or about 70F. Cooling isn't an issue being outside temps are around 0C or 32F and I can open windows more of less depending on temps.

These units should all have 3 points of power to fill the amperage that this thing uses. That means the 2 6 pin pci express connectors should be used and also the other 12v screw connections should be used. I'll be making adapters for my other rigs that will have a 6 or 8 pin pci-e female end that goes to a ring terminal so I can screw it on. All my boards were 100% factory stock settings from megabigpower and these were the V2.2 H cards that have adjustable potentiometer on them. I brought this up numerous times in the bitfury thread which I'll have to post the link where I brought my concern about this.

Thread where I mentioned my concern regarding overloaded power connectors..post 198

https://bitcointalk.org/index.php?topic=287590.msg3228270#msg3228270

Now the Pics (Click Pic to Expand)










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[JakeTri]

Both 6 pin PCIe connectors and the wires are really hot on my fully populated BitFury rig (october version). My PSU is Corsair AX860W Platinum.

Using default chainminer settings I get ~640W power usage at the wall. To reduce the loads on wires and PCIe connectors I created a custom best.cnf file and force reduce speed to 51. With this settings I got about 560W to the wall and wires/pcie connectors are worm to the touch but as expected the hashing performance is lower.

Do you know where can we order some 6 pin pci express adapters for the 12v screw connections ?

[AMD FTW]

Both 6 pin PCIe connectors and the wires are really hot on my fully populated BitFury rig (october version). My PSU is Corsair AX860W Platinum.

Using default chainminer settings I get ~640W power usage at the wall. To reduce the loads on wires and PCIe connectors I created a custom best.cnf file and force reduce speed to 51. With this settings I got about 560W to the wall and wires/pcie connectors are worm to the touch but as expected the hashing performance is lower.

Do you know where can we order some 6 pin pci express adapters for the 12v screw connections ?

You can order this part here, while its not the cheapest silverstone does make quality components. Then buy some ring terminals (blue or yellow colored is fine....just make sure the hole diameter isn't too large....Autoparts stores or hardware stores will have them) pictured below and solder it to cut power cable that you purchased. This should reduce the load on each 6 pin by 50%.

http://www.newegg.com/Product/Product.aspx?Item=12-162-036

http://www.google.com/imgres?imgurl=http://wiki.talkbass.com/images/6/63/Ring_terminal.jpg&imgrefurl=http://wiki.talkbass.com/index.php?title%3DFile:Ring_terminal.jpg&h=400&w=400&sz=7&tbnid=K8SsPEKGFXrRBM:&tbnh=92&tbnw=92&zoom=1&usg=__Cwgph3kXNHC914M8YXVsh3fOGcA=&docid=XbWIe9KxSihMVM&sa=X&ei=QJ2TUoTgJ5LroAS5voLgDg&ved=0CG4Q9QEwAg

[AMD FTW]

Both 6 pin PCIe connectors and the wires are really hot on my fully populated BitFury rig (october version). My PSU is Corsair AX860W Platinum.

Using default chainminer settings I get ~640W power usage at the wall. To reduce the loads on wires and PCIe connectors I created a custom best.cnf file and force reduce speed to 51. With this settings I got about 560W to the wall and wires/pcie connectors are worm to the touch but as expected the hashing performance is lower.

Do you know where can we order some 6 pin pci express adapters for the 12v screw connections ?

I only tested 2 units and they typically were taking 550-580 watts on stock settings. I tested it via a P3 Kill a Watt power strip

http://www.p3international.com/products/consumer/p4320.html

[Isokivi]

Thanks for posting, this led me to balance the load between my psu's. Had one with warm cables, hope swapping some h-boards to another m-board is sufficient.

[buzzdave]

Thanks for the details AMD - I'm sending this info to the developer and manufacturer - we'll make any necessary design changes immediately.

In the meantime, I hope everyone remembers these are high wattage devices that need special care - keep them away from anything flammable, similar to what AMD has done here.

Stay safe!

Regards
Dave

[greaterninja]

where's my quote???  hmmm?  

Yes, the resistor is 10k, but people are measuring it in-circuit and getting distorted values.

Oh ok, that makes sense now.

So another question for you. Do you happen to know what the masterboard rated safe wattage is. From what I've seen a full loaded bitfury setup takes around 400 watts. Being that there are 2 6 pin pci express connectors which are normally rated for 75 watts and an 8 pin is rated for 150 watts. Both the 6 pin and 8 pin have 3 hot wires while the 8 pin has 2 more grounds.

With an overclocked complete bitfury 400 ghash units possibly overclocked to 500 ghash or more, do you think the master board is capable of handling 500-600 watts through just 2 6 pin pci express connectors. I know most quality psu's use 18 ga wire which can handle 10 amps each (not that I'd want to run that much current through 18ga), would mean the wire is good for 600 watts, but is the masterboard capable of this?

Otheriwse it may be better to only run 12 overclocked boards in each master and just run additional masterboards and raspberry pi's to not over draw to much current

This is a major concern of mine as well.  I think some power supplies will get melted if OC and max capacity (all 16 slots) take place.

Putting 400-650 watts on 2 x 6 pin PCI-E power cables is risky depending on your power supplies.  Specifically, I learned this with 2 x 8 pin PCI-E cables on a 7990 Malta and Seasonic Gold 850 watt PSU.

Bitfury products are superior...but guys (customers)...please load balance your power and power cables per unit.

[Isokivi]

After some thinking (and testing) the real fire hazard is not the bitfury. It's that retarded pci-e cable, just use two of them (you got plenty with the pus's) and your good.

[edit] The cable is bad because it's insufiscient for the power needed, note that having two separate cables halves the load on the copper.
[edit2] Apparrently this conclution was allready reached.

[jimrome]

One of my rigs is V1 MB based and has been running heavily OC'd (>500GH/s across 16 boards) for months. I noticed yesterday that the white plastic male connectors (minifit jr 6P) were darkening (near the contacts) due to heat damage - fortunately there was no damage to the PSU or PSU cabling. The connectors were hot to the touch, likely due to the current handling capabilities of the pins are being exceeded. I'll upload a pic when I get home

This rig is in my basement which is very, very cool. PSU is a Corsair AX850. No damage has been observed on any connectors (board or cable) either on this rig or my other two. Heatsinks are installed on every HB and 3 HSFs per rig.

I'd advise everyone to check connectors regularly, and to exercise caution when overclocking.

[buzzdave]

One of my rigs is V1 MB based and has been running heavily OC'd (>500GH/s across 16 boards) for months. I noticed yesterday that the white plastic male connectors (minifit jr 6P) were darkening (near the contacts) due to heat damage - fortunately there was no damage to the PSU or PSU cabling. The connectors were hot to the touch, likely due to the current handling capabilities of the pins are being exceeded. I'll upload a pic when I get home

This rig is in my basement which is very, very cool. PSU is a Corsair AX850. No damage has been observed on any connectors (board or cable) either on this rig or my other two. Heatsinks are installed on every HB and 3 HSFs per rig.

I'd advise everyone to check connectors regularly, and to exercise caution when overclocking.

Thanks Jim - I second that emotion!

Folks please power your rigs with two *seperate* cables from the PSU.  Full rigs should probably use a 1000w or great power supply for safety's sake.  Check your rigs often.  This is all stuff we faced back in the GPU mining days

[tacotime]

I've been GPU mining litecoin/bitcoin for years and have never seen this .. the problem is that you're exceeding the 6-pin's capacity severely. These power cables are only intended to carry 75w each, while 8 pin connectors can carry 150w each.  If you intend to have these running at 600w as the latest rigs have been, you need 4x 8 pin connectors.  Why the designers chose to do something so glaringly out of spec is a mystery to me.

In the meantime, I would suggest that people begin connecting the 12v lines from molex or 6/8 pin adapters directly to the +/- terminals at the other end of the hboard in addition to the 2x 6 pin adapters. My rig is only pulling 390w, but both cables remain warm even at an ambient temp of 4C

[punin]

We've had this incident once (happened overnight) with a rig that had both cables plugged. How well they were plugged, that's another question. The Molex Mini-Fit Jr is an ok connector and should handle 13A on each circuit, but sometimes it doesn't connect properly and you get arcing and overheating. And sometimes PSU manufacturer saved by using thinner cable

[punin]

These power cables are only intended to carry 75w each, while 8 pin connectors can carry 150w each.

This is PCIe spec, not molex.

[tacotime]

These power cables are only intended to carry 75w each, while 8 pin connectors can carry 150w each.

This is PCIe spec, not molex.

Well, each 6 pin has 3x 18 gauge awg 12v + ins, which should hold 10 or 11 amps each in theory. That means a max wattage of 360 - 400w each, but you get pretty close to the max at 600w load. If the psu cheaps out and uses 20 or 22 gauge awg you will probably run into problems.

[Pentium100]

Folks please power your rigs with two *seperate* cables from the PSU.  Full rigs should probably use a 1000w or great power supply for safety's sake.  Check your rigs often.  This is all stuff we faced back in the GPU mining days

Or just solder big fat wires directly to the board and the PSU bypassing any connections that might cause you trouble.

Though I doubt that there would be any point in using a overpowered PSU other than efficiency. Any good quality power supply can handle full load (though I would modify them to spin their fans at full speed all the time instead of the "silent" nonsense). If you buy a low quality power supply, it can just blow up (shorting the outlet) because it uses active PFC and the primary cap dies (I have repaired one such PSU and have ordered parts to repair another).

[goxed]

One of my rigs is V1 MB based and has been running heavily OC'd (>500GH/s across 16 boards) for months. I noticed yesterday that the white plastic male connectors (minifit jr 6P) were darkening (near the contacts) due to heat damage - fortunately there was no damage to the PSU or PSU cabling. The connectors were hot to the touch, likely due to the current handling capabilities of the pins are being exceeded. I'll upload a pic when I get home

This rig is in my basement which is very, very cool. PSU is a Corsair AX850. No damage has been observed on any connectors (board or cable) either on this rig or my other two. Heatsinks are installed on every HB and 3 HSFs per rig.

I'd advise everyone to check connectors regularly, and to exercise caution when overclocking.

Thanks Jim - I second that emotion!

Folks please power your rigs with two *seperate* cables from the PSU.  Full rigs should probably use a 1000w or great power supply for safety's sake.  Check your rigs often.  This is all stuff we faced back in the GPU mining days

+1

[jimrome]

We've had this incident once (happened overnight) with a rig that had both cables plugged. How well they were plugged, that's another question. The Molex Mini-Fit Jr is an ok connector and should handle 13A on each circuit, but sometimes it doesn't connect properly and you get arcing and overheating. And sometimes PSU manufacturer saved by using thinner cable

Hi Punin, as I'm sure you know, 13A/pin is dependant on the type (and quality) of the pin used in the housing. I think it's quite possible, even likely, that the contacts used in the PSU adapters are the culprit, at least in my case.

[jimrome]

These power cables are only intended to carry 75w each, while 8 pin connectors can carry 150w each.

This is PCIe spec, not molex.

Well, each 6 pin has 3x 18 gauge awg 12v + ins, which should hold 10 or 11 amps each in theory. That means a max wattage of 360 - 400w each, but you get pretty close to the max at 600w load. If the psu cheaps out and uses 20 or 22 gauge awg you will probably run into problems.

Contacts (e.g. pins) have a current rating as well, which is independent from the capacity of the wire.

[Unacceptable]

Here's a decent chart for current capacities of AWG sizes 

http://www.powerstream.com/Wire_Size.htm

Learn it,live it.......or burn it 

Get male connectors from here,add the pins though,not auto included:

6pin:
http://www.frozencpu.com/products/8620/ele-361/FrozenCPU_ConnectRight_6-pin_Male_PCI-Express_Power_Connector_-_Black.html?tl=g51c385s1005

8pin:
http://www.frozencpu.com/products/8693/ele-369/PCI-E_8-pin_Male_Power_Connector_-_Black.html?tl=g51c383s1007

[AMD FTW]

After some thinking (and testing) the real fire hazard is not the bitfury. It's that retarded pci-e cable, just use two of them (you got plenty with the pus's) and your good.

[edit] The cable is bad because it's insufiscient for the power needed, note that having two separate cables halves the load on the copper.
[edit2] Apparrently this conclution was allready reached.

For a heads up, all my rigs use separate 6 pin pci-e power cords. You can see from my pictures that there are 2 psu cords plugged into that XFX 850. I didn't use one cable with 2 6 pin pci-e ends being that would be 550w through 18 ga wire which you'd fry in no time.