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Convert an ATX power supply into a regular DC power supply Answered

I did this project https://www.instructables.com/id/Convert-an-ATX-Power-Supply-Into-a-Regular-DC-Powe/ just today, but all the results came out negative voltage (e.g. -11,45 on the 12v) on the multimeter. Did I do something wrong or is it supposed to be like that?

Discussions

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Padlock

10 years ago

Do you have your multimeter leads crossed? (Assuming that your using a multimeter...)

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kithsoPadlock

Reply 10 years ago

Leads are fine and labeled anyway. All in all Im calling this one a success. It powers my 12v styrofoam cutter (homemade of course) just fine. Also tested it on some 12v pc fans and some other odds and ends.

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Padlockkithso

Reply 10 years ago

How do you power the Styrofoam cutter? ATX Power supplies cut out when they are short-circuited, and since the path has such low resistance I imagine it would cut out.

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kithso

10 years ago

Sorry for the back to back posts but heres the device in question.

100_0399.JPG100_0401.JPG
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guyfrom7upkithso

Reply 10 years ago

depending on your power supply, 12 volts may not be yellow. I think on mine yellow = 3.3 volts

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kithsoguyfrom7up

Reply 10 years ago

Yellow is coming up -11.45 on the meter

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guyfrom7upkithso

Reply 10 years ago

then that may be -12 volts from your powersupply

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kithsoguyfrom7up

Reply 10 years ago

All of the posts I made are coming up negative.

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purduecerkithso

Reply 10 years ago

*guyfrom7up* Any luck?
*kithso* negative, sir.

:-P

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kithsokithso

Reply 10 years ago

Decided to just go ahead and test it on some LED's. Worked ok but i accidentally crossed the wires and now I got nothin. Alas

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Plasmana

10 years ago

That sounds weird... Is your multimeter working fine? Test it on a battery or something like that.

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kithsoPlasmana

Reply 10 years ago

Yeah for some reason the new meter read everything negative but an old (really old) meter reads it just fine. I tested some more stuff on it today it seems to work so Im going to call this one a success.

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guyfrom7upkithso

Reply 10 years ago

can you take a pic of the meter?

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kithsoguyfrom7up

Reply 10 years ago

Heres a pic of both the old and new multimeter on the 12v rail. The needle on the old meter is set to test 10v dc because set to 50 it doesnt move really.

100_0403.JPG100_0405.JPG
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guyfrom7up

10 years ago

You 100% sure you didn't hook the wires up backwards? While power is off, using a continuity meter, check your "ground" with earth ground and the case, they should all register basically 0 ohms, if not then that's not really ground

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kithsoguyfrom7up

Reply 10 years ago

I did exactly as the ible said, when I checked the case itself for current I got something like a .03 or something similar. Didnt shock me when I touched it at least. Got all the black to ground, all the yellow to 12 and so on. Im fairly certain no wires are crossed or anything like that.