burninbush Posted January 17, 2015 Share Posted January 17, 2015 Hi folks -- got a little problem here. One of my desktop's power supply has been annoying me with the amount of noise it makes - fans - and so when newegg put a deal in front of me for a new quiet supply I took it. However, got it and installed it, but the mobo won't power up with it. After a couple hours of parts swapping I finally got around to examining the main 24-pin connector, to discover that the new supply had only 23 wires connected. The missing pin is normally a -5v supply. After trying several old PS I had available it seems certain that the missing -5v is why the mobo won't come up; those with that pin all would make the mobo POST, without it, no POST. Manual says absolutely nothing about needing it, I s'pose they just assumed that a standard would always be a standard. So -- is there some designation rev or other way to ID which sort of supply would include that voltage? What is -5v used for these days? Obviously not all mobos need it. My funky mobo is an ASRock with an AME-3 socket. And FWIW, my other desktop is also an ASRock mobo, and it doesn't need -5v. Quote Link to comment Share on other sites More sharing options...
Capt.Crow Posted January 17, 2015 Share Posted January 17, 2015 Send it back.. Quote Link to comment Share on other sites More sharing options...
b2cm Posted January 18, 2015 Share Posted January 18, 2015 (edited) The 24-pin connector will have only 23 pins connected. The 20th (preceded by 3 ground, followed by 3 +5V pins) pin is a NC. Try another power cable. Or test the PSU by shorting the pin 16 (green--PS ON) and one of the ground pins (the 3 that follows it). Edited January 18, 2015 by b2cm 1 Quote Link to comment Share on other sites More sharing options...
burninbush Posted January 18, 2015 Author Share Posted January 18, 2015 OK, I have done more research, and have found that there are 'Version 1.0' and 'Version 2.0' ATX power supplies. The 2.0 have a 24-pin connector but the last 4 pins are on a separable section, can be split so the 24-pin supply will plug into a 20-pin mobo socket. (the extra 4 pins on Version 2.0 duplicate voltages on other pins in the connector) So I apparently have a version 1.0 mobo which needs the -5v, but sellers like newegg are not distinguishing between the two types. Newegg still sells some 24-pin supplies that include the -5v pin, but you have to read the details to discover which they are. I have two PS here that still work so the mobo isn't dead just yet. Reckon it's time for a mobo upgrade. Meanwhile this is a pitfall for anybody with an older mobo that needs a new power supply. It isn't enough to just order an 'ATX' supply. The ATX 'standard' has apparently been revised 4 times since the 24-pin connector -- at version 1.2 the -5v pin became optional. Sorry to trouble you all with this -- just assumed that the mavens here would already know all about it. Quote Link to comment Share on other sites More sharing options...
Capt.Crow Posted January 18, 2015 Share Posted January 18, 2015 It's most likely that you will find exactly what you need in the local recycle yard . or charity shop . for which you will pay peanuts . Myself I just gather the old stuff from "dumpsters" This may not be an option for you especially if you are tight for storage . It's very rare that I don't have something that I can use for a work around . I picked up 4x 1gb ram cards the other day . Still in the wrappers. Quote Link to comment Share on other sites More sharing options...
abarbarian Posted January 19, 2015 Share Posted January 19, 2015 It's most likely that you will find exactly what you need in the local recycle yard . or charity shop . for which you will pay peanuts . Myself I just gather the old stuff from "dumpsters" This may not be an option for you especially if you are tight for storage . It's very rare that I don't have something that I can use for a work around . I picked up 4x 1gb ram cards the other day . Still in the wrappers. That is some posh dumpster. We would be lucky to get the wrappers. Quote Link to comment Share on other sites More sharing options...
b2cm Posted January 19, 2015 Share Posted January 19, 2015 The ATX 1.3 standard did away with that -5V pin more than 10 years ago because it was useless. You had to have a mobo with ISA slots and use an ISA card to need that -5V pin. 1 Quote Link to comment Share on other sites More sharing options...
Capt.Crow Posted January 19, 2015 Share Posted January 19, 2015 Well you just have to be lucky enough to pass by when the builders are clearing out a house/shop/apartment prior to refurbishment. Quote Link to comment Share on other sites More sharing options...
abarbarian Posted January 19, 2015 Share Posted January 19, 2015 Well you just have to be lucky enough to pass by when the builders are clearing out a house/shop/apartment prior to refurbishment. Indeedy, I remember finding a huge industrial fan 30" with shroud in a skip. I checked that it spun freely and was going to cannibalise it for a project but on a whim I fitted a plug and it worked as smooth as silk and very quiet. So I stashed it in the garage and sold it to a builder chappy who made a portable extraction unit out of it. He was happy and so was I with the £40 I made (ten years ago). 1 Quote Link to comment Share on other sites More sharing options...
Capt.Crow Posted January 20, 2015 Share Posted January 20, 2015 That 40quid came in very handy "no doubt" . Anything I bring home that doesn't work get broken down for the metals or goes up the chimney for free heat . Have you seen the price of copper these days. Quote Link to comment Share on other sites More sharing options...
Guest LilBambi Posted January 29, 2015 Share Posted January 29, 2015 http://www.metalprices.com/p/CopperFreeChart Quote Link to comment Share on other sites More sharing options...
Capt.Crow Posted January 30, 2015 Share Posted January 30, 2015 Last time I looked it was 3200euro the ton . Quote Link to comment Share on other sites More sharing options...
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