for those having power supply problems - I am interested what your room temp is at. if i understand correctly higher temps = lower efficiency so you cannot expect the power supply to perform the same at 60 degrees F (15.5 Celsius) vs 80 degrees F (26.5 Celsius). this also would make a difference as to where it is pulling air from (inside the case B2's vs outside the case B2's). i for one replaced mine about 2 hrs after receiving it due to the fact that i wanted to overclock it (if possible). but i did not have any problems with my unit using the stock PS with the room temp at 60 degrees F or below.
short term a cool room the psu will work. long term it is under sized.
be smart pull a blade all worries vanish. this may be the best solution for almost all owners of the gear.
another fairly cheap solution is to replace the power supply with something beefier. my personal recommendation (and what I did for myself) is to spend around $150 and purchase 2x of these 750w kits -
http://www.gekkoscience.com/products/server_supply_breakout_board.html - and run them with power sharing pins and you have more than enough for the S2 (unless we figure how to overclock past 250mhz) and enough for 3 overclocked S1's. and if you have one of these power supplies go bad you can replace it for a cheap $25 from ebay. i keep an extra few on hand for myself anyway for rapid deployment for myself and customers. if you want more info on the maker of these you can read this thread -
https://bitcointalk.org/index.php?topic=379677DISCLAIMER: I am in no way affiliated or compensated by sidehack for this recommendation. he has a decent product and i feel he should make money for his work and research.
EDIT: here's pictures of my setup
[img ]https://dl.dropboxusercontent.com/u/23772269/2x%20power%20supplies%20in%20tandem.jpg[/img]
[img ]https://dl.dropboxusercontent.com/u/23772269/top%20view%20case%20off.jpg[/img]
[img ]https://dl.dropboxusercontent.com/u/23772269/top%20view%20with%20case%20on.jpg[/img]
Thats to tell you how cheap these products are....
Cheap PSU (yike), cheap board design and cheap casing. Yet not very competitive price.
Seeing your pics, i'm wondering how the heck someone can even call this a 4u rackmountable miner. Btw... ppl should stop putting consumer desktop PSU in a rackmountable server case. The 120mm PSU fan isnt designed to take warm air....