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Power supply question
sreed Jan-17-01 11:41 PM
I was given a couple of 486's that I would like
to connect to an ethernet LAN as diskless nodes.
I have been trying to locate some cheap *fanless*
power supplies for them. I haven't checked on the
prices yet, but I've found some at the following URL:


My question is this.. What type of outputs would
I need to power only the AT system board and PCI
ethernet. Could I make do with a single +5? I won't
be needing a floppy drive since I'm putting bootp
roms on the NIC's, they have integrated video, and
I won't be using any of the ports except the ps/2

I would also welcome any suggestions on an alternate
brand or something too. Cost is a major factor.


1. update..
sreed Jan-18-01 06:31 AM
In response to message 0
The ethernet cards I ended up getting (taking what I can get for free) are ISA, not PCI. I am guessing that this will affect my power requirements so I thought I would add that in case anyone can help.

2. RE: Power supply question
lbyard Jan-18-01 06:39 PM
In response to message 0
You have more to contend with than just 5 volts. Voltage regulation is a major consideration and the power supply has to generate a power good signal so the motherboard will not start to boot until the power supply voltages are stable. That could be fudged because the power good signal is about 5 volts, but I would guess it would cause boot-up stability problems. You can probably get away with just +5 volts regulated, but some old motherboards may need 5 volts. Some need +-12 volts for serial interfaces, if there are any. The power supply fan cools both the power supply and the rest of the computer. I would want that fan on a hot summer day. In my experience--which was a very long time ago and with Novell servers and long enough ago that I do not remember the exact details--a boot floppy was a more practical solution than a boot ROM. A floppy is easier to change. AT power supplies are getting very difficult to find. If you open an AT power supply, please remember, if it is on, there are dangerously high voltages inside. You may even get zapped after unplugging it if you reach inside before everything has had sufficient time to discharge. Larry

3. RE: Power supply question
sreed Jan-18-01 09:19 PM
In response to message 2
Thanks a trillion lbyard. This helps bigtime.

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