sardella@world.std.com (Norman R Sardella) (03/20/91)
Can the 3b1 power supply handle 2 fans wired to the power supply the same way as the 7300 power supply fans are wired. I need this for an external hard. -- Norman "Stormin" sardella Leisure: sardella@world.std.com Home: uunet!world!stormy!norm Work: sardella@sud509.ed.ray.com
floyd@ims.alaska.edu (Floyd Davidson) (03/21/91)
In article <1991Mar20.141053.3852@world.std.com> sardella@world.std.com (Norman R Sardella) writes: >Can the 3b1 power supply handle 2 fans wired to the power supply >the same way as the 7300 power supply fans are wired. I need this for >an external hard. >-- >Norman "Stormin" sardella >Leisure: sardella@world.std.com >Home: uunet!world!stormy!norm >Work: sardella@sud509.ed.ray.com Use an AC fan. That takes the load completely off the power supply. While you are at it, get two fans and replace the DC one in the 3b1 and you will take a little more load off the supply. Floyd -- Floyd L. Davidson | floyd@ims.alaska.edu | Alascom, Inc. pays me Salcha, AK 99714 | Univ. of Alaska | but not for opinions.
renkel@motcid.UUCP (Will Renkel) (03/21/91)
Last fall I had an "overheat" problem when the single fan in my 3b1 was freezing up. The solution - remove the styrofoam by the other inlet and install a second fan using the same power supply. Why should it work? According to an ATT source, the 7300 had the same powere supply setup and 2 fans. In fact, dont know why the second fan was rfemoved from the 3b1. ------------------------------------------------------------------------------ Will Renkel - Motorola - Cellular 1501 W. Shure Drive - Room N258, Arlington Heights, IL 60004 (708) 632-4416 - ...uunet!mcdchg!motcid!renkel ------------------------------------------------------------------------------
murphyn@motcid.UUCP (Neal P. Murphy) (03/22/91)
renkel@motcid.UUCP (Will Renkel) writes: >... >the 7300 had the same powere supply setup and 2 fans. In fact, dont know why >the second fan was rfemoved from the 3b1. The second fan was removed because it didn't add to the cooling. In fact, it would appear that the machine runs cooler with just the one fan pulling air across the power supply. The 3B1 has a power supply that yields an extra 20-50W of power - needed for the bigger disk drives, I imagine. NPN
floyd@ims.alaska.edu (Floyd Davidson) (03/22/91)
In article <6744@bone13.UUCP> murphyn@motcid.UUCP (Neal P. Murphy) writes: >renkel@motcid.UUCP (Will Renkel) writes: > >>... >>the 7300 had the same powere supply setup and 2 fans. In fact, dont know why >>the second fan was rfemoved from the 3b1. > >The second fan was removed because it didn't add to the cooling. In fact, it >would appear that the machine runs cooler with just the one fan pulling air across >the power supply. > >The 3B1 has a power supply that yields an extra 20-50W of power - needed for the >bigger disk drives, I imagine. > >NPN The second fan, if it blows outward, causes a vacuum in the center area of the motherboard. The way around that is to put the fan in the way fans should be, blowing inward so the air can be filtered. Unfortunately the fan by the power supply will spread the heat all around the machine if it is reversed to blow inward. Replacing the fans with AC units takes the load off the DC supply, which is nice, but they are always at full speed and thus make more noise. An AC fan will be more reliable. If the machine starts up cool enough that the DC fan is on low speed, and the fan is old and the bearings worn, the fan may not start. The fan itself then heats up and becomes impossible to start, even when it gets full voltage for high speed (which it will as soon as the power supply overheats). The power supply overheats and shuts down, and recycles itself. Sometimes the case above the power supply melts... Some times the power supply melts... What I've had for three years is two AC fans, with the second one blowing inward and with a filter on it. I put the second fan in before the DC fan went bad, which it eventually did. No problem... It was then replaced with an AC fan. My 3b1 sounds like a 747 but I don't worry about a meltdown either. Floyd -- Floyd L. Davidson | floyd@ims.alaska.edu | Alascom, Inc. pays me Salcha, AK 99714 | Univ. of Alaska | but not for opinions.