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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: lorddef on July 19, 2003, 06:01:52 PM

Title: AT Power Supply Pinouts
Post by: lorddef on July 19, 2003, 06:01:52 PM: I'm trying to rig up the power to my Micronik busboard as explained in this thread (http://www.amiga.org/forums/showthread.php?t=3216).

I need to know what wires are what on the AT psu (more specifically the one in the eyetech mk3 tower).

I know blue is 0v but that's it. I could just take the power from a molex connector, but I'd rather take it from the mobo connecters.
Title: Re: AT Power Supply Pinouts
Post by: KennyR on July 19, 2003, 06:09:00 PM: Are you sure blue is 0V?? In my eyetech tower it's -12V!
Title: Re: AT Power Supply Pinouts
Post by: lorddef on July 19, 2003, 06:33:02 PM: oooooh good call !!!

nearly made my Amiga go bye bye there. Anyhow once I get pinouts for the AT PSU I'll be okay.
Title: Re: AT Power Supply Pinouts
Post by: Gaidheal on July 19, 2003, 06:33:04 PM: Blue is NOT 0v it is -ve 12V.

Only the BLACK (ground) are at 0v relative to all other supplied voltages.
Title: Re: AT Power Supply Pinouts
Post by: lorddef on July 19, 2003, 06:36:13 PM: @Gaidheal

by relative do you mean that I need a different 0v for each other voltagethe mobo uses? (my micronic board has 3 x 0v inputs) Or can I just take 0v from one source?
Title: Re: AT Power Supply Pinouts
Post by: iamaboringperson on July 19, 2003, 06:38:44 PM: Quote
once I get pinouts for the AT PSU I'll be okay.
i cant remember the name of this resourse... it used to be on amiga cover CD's and i think its online
'the hardware book'?
is that it - that has many pinout charts
Title: Re: AT Power Supply Pinouts
Post by: Gaidheal on July 19, 2003, 06:38:47 PM: PC AT PSU:

Orange = "power good"

Red = "+ve 5V"

Yellow = "+ve 12V"

Blue = "-ve 12V"

Black = ground (0v)

White = "-ve 5V"

Hope this stops you toasting the sucker :¬)
Title: Re: AT Power Supply Pinouts
Post by: Gaidheal on July 19, 2003, 06:42:13 PM: Just so you are clear, GROUND is GROUND. It is the potential relative to which all the other voltages are stated. The REAL potential of the +12V line, to the actual floor, might be 20,000V. But in that case the ground line would be 19,988V. Do you follow me?

So, no it matters not, all the black wires are at the same potential. Which as far as your motherboard is concerned, is 0V

P.S. If your PSU was at that kind of potential, nasty #### would happen.. like arcing to ground. So don't worry, it isn't :¬)
Title: Re: AT Power Supply Pinouts
Post by: lorddef on July 19, 2003, 06:46:12 PM: Ah, I get you.

Ta very much for the colour codes!
Title: Re: AT Power Supply Pinouts
Post by: Gaidheal on July 20, 2003, 05:28:30 AM: Most welcome :¬)

I live to serve.
Title: Re: AT Power Supply Pinouts
Post by: Ni72ous on July 20, 2003, 09:44:54 AM: @Gaidheal

This might be a stupid question but waht does the VE stand for?
Title: Re: AT Power Supply Pinouts
Post by: Gaidheal on July 20, 2003, 04:12:56 PM: No.. not a stupid question.. honest answer? It's so intuitive to me, that I can no longer remember. But it is standard practice, with many fields but definitely in electronics to write "+ve" for positive and "-ve" for negative, wrt to potentials where "positive" is "a potential which will result in a current flowing in the same direction as conventional current" As I recall. Some of this seeems a bit verbose.. and to be honest it is. In part here is why...

A "Potential Difference" (aka voltage, as far as this conversation is concerned) is exactly that. A difference in potentials. For an analogy, imagine two building, whose rooves are at different heights. The diference is 2 metres. So we have a "height difference" of 2m. Now, as alluded to earlier.. the "potential" to the ground could be a lot more. Let's say both buildings are large and tower around 400m into the air. The "height difference" to the ground is 400m and 402m respectively! We definitely do not want to fall to ground from either.. but we MIGHT want to jump from one to the other. Now, let us define a CONVENTION that travelling from left to right is POSITIVE flow. It turns out that the building on the left is the taller, which means we have to jump left to right (unless we can fly!) so we now have a "height difference" of +2m. If the taller building were on the right, it would be -2m since we would have a difference that OPPOSED our conventional flow model. OK, this 'conventional' bit, what is that about? Well, it turns out that in fact current flows the other way :¬) This is because electrons are NEGATIVELY charged. At the time this was not known and an arbitrary convention was needed. They had a 50/50 chance of being 'correct'... they were not.

Good luck wading through that, and I know it was tangential!

John

edit: corrected a spelling mistake and changed "left" to "right" in second sentence about "jump flow" :¬) Doh!
Title: Re: AT Power Supply Pinouts
Post by: Ni72ous on July 20, 2003, 04:16:41 PM: @Gaidheal

Thank You.
Title: Re: AT Power Supply Pinouts
Post by: bloodline on July 20, 2003, 05:03:04 PM: Quote

Gaidheal wrote:
Most welcome :¬)

I live to serve.

No, no ,no... noooo.... You live to *Emulate* ;-)
Title: Re: AT Power Supply Pinouts
Post by: Gaidheal on July 20, 2003, 05:03:51 PM: Welcome
Title: Re: AT Power Supply Pinouts
Post by: Gaidheal on July 20, 2003, 05:05:19 PM: LOL

I was in an odd mood when I typed that... :¬)

Just been looking for a job, with this minimized, so I missed your reply, because it was posted before I submitted mine.