On Sun Feb 28 9:00 , Henrik /KaarPoSoft sent:
>> >>> Dear all, >>> >>> I have a net5501, which seems to work with a Kingston 64GB SSDnowV+ >>> (SATA) and Seagate Barracuda 7200.7 (3.5" 160GB) SATA. >>> However, I can not get it to work with my Seagate Barracuda ES SATA >>> 3.0Gb/s 750-GB Hard Drive (ST3750640NS). >>> >>> The 750G Barracuda has worked fine for a year in my Dell PowerEdge T105, >>> and I put FreeBSD 8.0 on it using my Dell OptiPlex 8400, where it also >>> works fine. >>> >>> However, when I put the 750G Barracuda in the net5501, it does not get >>> past POST. >>> Most of the time I get to >>> POST 0123456789bcefgh >>> sometimes to >>> POST 0123456789bcefghip >>> and sometimes it even starts to check memory, but does not get past the >>> 0000 Mbyte >>> >>> Once it acutally got past POST and into the ComBIOS, but the drive still >>> not visible. >>> >> >> This, to me, suggests a power issue. When my Soekris supplied wall warts >> started >> to go, I'd get behavior like that on my 5501 with just a CF card. Assuming >> you're powering the drive through the Soekris and it draws more power than >> the >> other two drives, it could be you're over taxing the power supply. You >> could try >> an experiment and try to find a way to power the drive externally. >> >> >Hi Jed, > >Thanks for the suggestion! > >I am an absolute newbee on embedded and power issues ))-: > >According to the specs the SSD will draw 3.5 -4.2 Watts on operation. >The Barracuda 7200.7 160Gb (which works) draws 12 Watts average on >operation according to spec. >The Barracuda ES 750Gb (which does not work) draws 13 Watts average on >operation according to spec. >However, according to specs both the Barracudas draw up to 2.8 amps on >12V, i.e. a mighty 33.6 Watts on spinup. >So I guess the problem could be that the voltage is dropping during spinup. > >Everything is powered through a 12V, 1.5A C8 power supply (supplied by >Cortex); i.e. 18 Watts. > >I have searched the Soekris specs, but I cannot figure out how much >power the net5501 itself needs, neither how much power it can supply to >the SATA disk. I think this was discussed on the list a little while ago. Maybe it got captured on the wiki, but it should be in the list archives. And that may have been one of those times Soren made a definitive statement. >Would it make sense to purchase another external power supply (e.g. 12V, >3A), or does the Soekris net5501 internally limit the possible power to >the SATA disk, now matter what the external power supply can deliver? I'd think that would be the next thing to try, assuming someone else doesn't come up with a definitive alternative solution. Obviously there are practical limits to the current going through the net5501, e.g. I'd think 200A might tend to convert circuit traces into blown fuses. And the net5501 web page does mention a 20W limit on the external DC input to the 5501. >(I don't think I want to experiment with powering the drive "externally") You could use the PC you built it on as a power supply, being careful with grounding. Borrowing an external disk enclosure would be better if that's an option. HTH, -Jed _______________________________________________ Soekris-tech mailing list [email protected] http://lists.soekris.com/mailman/listinfo/soekris-tech
