I have finally got these two bad girls reasonably stable at asic temp of 68c and power module at 44c/45c
Note the evo 212 coolers are lifted 15mm up. This has reduced the cold airflow over the power modules.
after I used the "Hairdryer Mod" the boards would restart, but the temp. at the power modules would slowly fall.(eventually crashing again)
The cardboard cover is (hopefully) holding the temp. in the power modules and the cold air from the evo is deflected upwards.
The secondary fans are controlling the airflow under the boards, if I move them around then the temp. does change.
https://www.dropbox.com/s/y6dc59y5zzeaub5/IMG_20140110_105218.jpgEDIT still hashing after 3 hours
EDIT 2 crashed after 5 hours
Hello
I have also some crashs during last days from low voltage reset boards, at this moment ( not yet totally confirmed ) i suspect form internet connection: when it stops during few seconds (maybe or more than 30 seconds) boards lower the hash and cool down enough to be unable to restart by its own. Normal boards aren't affected. Discovered this during a router restart.
I changed setup putting this board on not cooled area: hash will be lowered but expect more immunity from connection drop-outs
Regards
For some reason these "low voltage reset" boards need a lot more heat ABOVE the power units, they still need the normal asic cooling and they do benefit from underside cooling(when the board is hashing)
It has to be something to do with the switching state in the power modules.(trying to move up to the next stage before all the temperature conditions are met)
That's why the "hairdryer mod" works.(It brings the temperature up in time for the switching to work)
The problem is that if I remove my "heatshield" after hashing starts, the temperature falls and the "crash happens again".
1. In a normal startup state, the board crashes after just a few seconds(never reaching the stable temperature of the asics or power module)
2. With the "hairdryer mod" the board gets to temperature and starts to hash, then the temperature starts to drop, it crashes after 3 or 4 minutes.
3. Adding the secondary cooling to the bottom of the board, the asic temperature continues to rise towards 70c and the hash speed rises, but the temperature in the power module continues to drop.
It again crashes after about 3 or 4 minutes.
4. With the "heatshield" placed over the power module, the temperatures stay reasonably stable, but I have not managed to keep it hashing for more than about 5 hours.
They readily restart, with the above "conditioning"
I have 7 boards that need this treatment, so a solution will be desirable.
My 8 other boards are well behaved, apart from the rPi deciding to reset occasionally.
