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Reply With QuoteThat is pretty much what I concluded when I posted this:
Current Testing
I was experimenting with the FV24, and figured out it doesn't need the -12 and -5, which makes the power supply much easier. It also hardly using anything on the +12 line.
So..
I'm going to use the MAX787 and MAX 788 for the +5 and +3, then a MAX642 for the +12.
Should be pretty simple, the 787, 788 and 642 only need a few capacitors, resistors, and an inductor to get them working.
I'll basically be using the +5 and +3.3 of the sproggy ( http://sproggy.mp3car.com/psumk25/psu2-5_schematic.pdf ) and create my own similar +12.
MA642: http://dbserv.maxim-ic.com/quick_view2.cfm?qv_pk=1327
Sound good?
That is pretty much what I concluded when I posted this:
Current Testing
MPEGBOX - Plexiglass Computer
www.mpegbox.com
Guess I need to keep up with the power supply forum more often, then
Although it doesn't seem to use the 12V without the fan, the FV24 doesn't seem to want to run without it.
Does it check the rpm of the fan and shutoff if the fan stops? Or does it need the +12 for something else?
If it doesn't need the +12, I could just run the fans unregulated off of the car voltage, and I would have an even easier to make PS!
Since it monitors the +12 in the bios, I assume that it doesn't post unless it sees something reasonable for +12
No, it doesn't look at the fan. I run it with out the fan all the time and not all fans have the rpm wire.
Just because your meter can't measure any draw on the minus 12, it may still use it for the serial port.
It looks like the ohm meter thinks that something is hooked up to the minus 12.
I can say with 99% conf that it doesn't use the -5 though.
Jeff
MPEGBOX - Plexiglass Computer
www.mpegbox.com
I actually cut the -12 and -5 lines. It's run fine all day.
serial / ps2 / video / audio / usb / ethernet all still work fine.
what kinda processor are you running that thing with? you really think a modified sproggy will hold up?
I have a celron 900. at 100% cpu usage, it uses 4A on the +5, and 1.9A on the +3.3
Im running a dreamcast off the sproggy and its practically maxing it out
arb, if you get your idea working i will pay you good money for the smallest fv24 psu availible!! stay in touch
Actually, I think that's the same plan that Jeff Mucha used to make his PSU so small.
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