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squirrel-steam
June 28th, 2008, 02:48 PM
I have a quantex with a Am486dx4-S 120mhz and im thinking of gutting it and using the case for a retro styling case for my gaming computer, it has a little mhz display on the front. I think it runs on 5v power, but i took my volt meter and hooked it up to the leads for it (it runs on a special connector directly from the power supply,) and it showed up as 3.3v. Confused, I connected the voltmeter to the 5v wires on the molex adapters from the power supply, and it showed up as the same 3.3v. Then i tested the 12V leads, and it showed up as 10v. I think the power supplies they used in them (AGI,) were pretty spotty. This computer had it replaced in '97. So I guess after 11 years, you might see some drop in voltage. But I can't believe the comptuer runs so good on that large of a drop of voltage.

Also, do you guys think its ok to gut that computer (it actually was a pent 1 75mhz, but i downgraded it to a am486dx4-s cpu,) or should i keep it. It would make a really cool new case mod.

Druid6900
June 28th, 2008, 06:58 PM
I doubt the computer would work if the 5VDC was actually at 3.3VDC

That's WAY outside the tolerance range and almost a 40% drop from ideal.

A 486 system wouldn't draw that heavily on the +12VDC line and it's below tolerance as well.

I suspect that your meter is out by around 2V DC

modem7
June 28th, 2008, 10:30 PM
it actually was a pent 1 75mhz, but i downgraded it to a am486dx4-s cpu,
The Pentium 75 runs on 3.3V (see http://en.wikipedia.org/wiki/Pentium).
So it sounds like you have an ATX power supply (see http://www.playtool.com/pages/psurailhistory/rails.html), found the +3.3V line, but have yet to locate the +5V line.

squirrel-steam
June 29th, 2008, 09:11 AM
Yes, it is atx, but I was taking the voltages from the molex adapters for a hard drive/cd drive.

I'll have to check that meter with another power supply. It might be bad, but its a 1500 dollar one my dad had from when he worked at waterlift (where they made the legs for the lunar lander.)

Druid6900
June 29th, 2008, 11:12 AM
Well, it just seems that, if you added 2V to the readings you got they would be close to ideal.

Since you say the system works, the voltages on the those two lines would have to be within, oh, plus or minus 10% or strange things would start happening

IF you the voltages were as you indicate, a switching supply probably wouldn't even tick over.

squirrel-steam
July 2nd, 2008, 07:43 AM
incorrect fuse in the volt meter, replaced it with a correct one, now it shows up to 4.9v, and 12.2v.

Druid6900
July 2nd, 2008, 11:45 AM
incorrect fuse in the volt meter, replaced it with a correct one, now it shows up to 4.9v, and 12.2v.

Much better.

modem7
July 3rd, 2008, 04:03 AM
I'll have to check that meter with another power supply. It might be bad, but its a 1500 dollar one my dad had from when he worked at waterlift (where they made the legs for the lunar lander.)

incorrect fuse in the volt meter, replaced it with a correct one, now it shows up to 4.9v, and 12.2v.
Well, that explains some of the problems that NASA had with the Lunar Lander all those years ago.

Dwight Elvey
July 3rd, 2008, 02:25 PM
incorrect fuse in the volt meter, replaced it with a correct one, now it shows up to 4.9v, and 12.2v.

Hi
I'd love to know how a fuse can effect the voltage read by a meter??
Dwight

Druid6900
July 3rd, 2008, 02:52 PM
Well, I was thinking about that too, and, the only thing I could think of would be a voltage divider set up by the resistor in a slo-blo fuse.

squirrel-steam
July 3rd, 2008, 06:17 PM
Well, it hasen't been replaced in about 10 years because of lack of use, and apparently was a corroded paper clip, I guess I should have specified that instead of saying "incorrect fuse." Probalby why the "fuse" didn't blow when it was on the 12v leads, and i set it to 2.5v dc. I wonder how it withstood that big of a overload without blowing.

modem7
July 4th, 2008, 02:35 AM
What? Substituting a fuse with a paper clip. What incompetence. Everybody knows that you use a nail.

Druid6900
July 4th, 2008, 11:35 AM
What? Substituting a fuse with a paper clip. What incompetence. Everybody knows that you use a nail.

Oh, puh-leeze...

Nails are SO 1900s

A 15mm depleted uranium slug from a Phalanx anti-missile system is what ALL the cool people are using.

modem7
July 4th, 2008, 05:37 PM
Oh, puh-leeze...
Nails are SO 1900s
A 15mm depleted uranium slug from a Phalanx anti-missile system is what ALL the cool people are using.
Thanks so much for bringing me up-to-date. Do I feel like an idiot now. I got to keep up with the trends. I only just found out that LOL doesn't stand for Little Old Lady, which is a relief because I had got the impression that a few forum members were women in their nineties.

squirrel-steam
July 5th, 2008, 01:09 PM
Well, at least it wasen't a loaded .22 bullet. Hmm, it would fit...

Druid6900
July 5th, 2008, 03:27 PM
@Modem7 - Oh, don't feel badly. If you don't subscribe to the "Fantastic Fuses" mailing list, how could you possibly know? :)

@the squirrel dude - yeah, why don't you try that out and let us know how it works for you. If we don't hear from you for a while (or forever), we'll know :)

carlsson
July 6th, 2008, 01:30 AM
I'd save the bullet for those computers who refuse to work properly and I don't bother trying to troubleshoot - I'd just remove "trouble".