There is input voltage monitoring, and an overvoltage shutdown if the input voltage goes over spec. It could be possible that if your supply is idling quite high and there is some voltage sensing circuitry on the supply that isn't connected, you could have enough overshoot to trip that protection. It would be hard to see with a multimeter, but you could be going over 13.2V.
Try connecting the voltage sense lines as klondike_bar suggested to get the voltage back to 12V, and see if that fixes the issue.
This sounds like the most likely candidate to me. In my testing these supplies operate at the high end of the ATX accepted range though still within it. What is the exact voltage cut off for the habanero to shut itself down if it is less than the accepted range it could be causing the shut down.
The current sense wire that people are talking about is already connected on these boards. What is the voltage range that the Habanero accepts is there any way to adjust that to see if that is the issue?
ATX spec is +/-5%, up to a maximum of 10% at peak loading. The VRM will shut down after I believe 5ms above 13.2V.
I agree, under load I typically measure 12.55v and 12.8 max when not loaded and with no connectors attached. Should be well below 13.2v though. Unfortunately I don't have a Habanero to play with so it is hard to diagnose what the issue maybe remotely.
Edit: To close the loop on this I'm told a firmware update fixes this issue.
Thanks MrTeal and thread members for all your help.. Everything is running now! No power issues.
What fixed it was a firmware update (Specially made from the PepperMining guys to handle the voltage with the Gigampz setup).
Having 9 (2 more to go, but had to leave the country on work stuff) Habaneros setup you can image the heat! I am now looking for ways to lower the heat so I can push the MHz up.
Ambient temp in this country (34 degrees Celsius outside) is unfortunately an issue as well, so aircon is running to try and keep the room at about 24 degrees Celsius.
I have a 30" industrial ventilation fan running which pushes about 10,000CFM but I feel the coverage area isn't big enough for 9 Habs on multiple shelving.
My next thought would be to have 2 fans at either end of the Hab board moving air across it and away from the board. Or maybe only a single 250CFM fan is needed.
Any fan recommendations?
Anyone have 5+ Habs in a single room? How are you handling cooling?
