ATX Connector

[bigbeark]

On the 24-pin ATX connector, the 4-pin part is frequently "detachable".
So when you detach, you have a 20-pin connector, however this 20-pin connector is missing one wire.

Many PSUs come with an adapter, into which you plug both pieces (20 + 4)and the other end, to plug into your motherboard has 20 pins.

What is the impact of plugging the "un-adapted" 20-pin into your motherboard? Can this damage your 20-pin motherboard because of the "missing" wire?

[Th3_uN1Qu3]

Re: ATX Connector

The 20-pin connector is missing the -5v wire. Not a problem unless you are running a PIII era board.

[bigbeark]

Re: ATX Connector

Right you are. I checked the documentation on my Tyan Tiger S2460 motherboard and it says any PSU to ATX 2.03 standard which omits the -5volt connector, so that's OK.

The question is, why did I pop CPU#1 on startup with my Thermaltake TR2 $30W PSU(new).

The lable calims to supply 30W on both the 3.3 and 5v rails, which is what this mobo requires. I looked up some tests of this PSU which says it can't in fact, deliver those AMPS.

Is falling short on AMPS likely to blow the CPU?

[shovenose]

Re: ATX Connector

You popped the cpu.
What do you mean, you fried it?

[bigbeark]

Re: ATX Connector

You popped the cpu.
What do you mean, you fried it?

Yes. I smelled something burning and saw the magic smoke coming from the vicinity of CPU#1. Both CPU fans were spinning, but no post.

[shovenose]

Re: ATX Connector

Oops. Btw the extra four pins 21-24 are one extra each of 3,3, 5, 12v and one ground. This has to do with the pci express port

[dood]

Re: ATX Connector

Wow... dual Socket A and it doesn't have a 4 pin aux connector? I'm surprised it doesn't melt the ATX connector.

Here's what Tyan has to say about a typical configuration:

TYPICAL PSU:

5V = 30+A TYPICALLY
300+W ATX 2.03 PSU (minimum)


TYPICAL System:

2 AMD Athlon MP 1.2GHz CPUs
4 256MB PC2100 DDR Memory Modules
1 4X AGP video card
2 ATA-100 IDE Hard Disk Drives (HDDs)
1 Floppy Disk Drive (FDD)
1 CD-ROM Drive
1 Sound Card
1 Gigabit LAN Card


Keep in mind, that's only 1.2ghz CPUs. What do you have in it? Also, keep in mind... Watts and amps are not the same thing! You need to make sure that PSU is capable of delivering 30 AMPS on the 5v rail.

[dood]

Re: ATX Connector

Also, I've seen adaptors to go from a 20 pin PSU to a 24 pin motherboard, but never from a 24pin PSU to a 20 pin motherboard...

[mathog]

Re: ATX Connector

Oops. Btw the extra four pins 21-24 are one extra each of 3,3, 5, 12v and one ground. This has to do with the pci express port

A lot of motherboards with PCIe slots will work fine with a 20 pin supply plugged into their 24 pin socket - so long as the PCIe slot is empty. The socket is keyed so the 20 ping plug has to go in the right way. (One down side, the plug "clamp" will not engage the little stop on the socket.) I have a couple of Asus A8N5X boards running this way. The do have itty bitty PCI graphics cards in them, but these are only used to set up (get to the BIOS). When the boards are running the cards stay in text mode, not even a basic windowing environment running. These boards with single core Athlon 64 3700+ cpus consume 60W when idle (clock drops to 1000MHz) and 110W when running cpuburn (clock jumps to 2200 MHz). In other words, minus a power sucking PCIe graphics card the power requirements for the rest of a computer can be quite modest.

[shovenose]

Re: ATX Connector

You can run it with a 20pin even with a geforce 9800

[Th3_uN1Qu3]

Re: ATX Connector

You can run it with a 20pin even with a geforce 9800

The 9800 has an auxiliary power connector and it gets most of its juice thru that.

[shovenose]

Re: ATX Connector

Not the 9800pe version. Has no pci-e power plug.
Pe=power efficient

[bigbeark]

Re: ATX Connector

Wow... dual Socket A and it doesn't have a 4 pin aux connector? I'm surprised it doesn't melt the ATX connector.

Here's what Tyan has to say about a typical configuration:

TYPICAL PSU:

5V = 30+A TYPICALLY
300+W ATX 2.03 PSU (minimum)


TYPICAL System:

2 AMD Athlon MP 1.2GHz CPUs
4 256MB PC2100 DDR Memory Modules
1 4X AGP video card
2 ATA-100 IDE Hard Disk Drives (HDDs)
1 Floppy Disk Drive (FDD)
1 CD-ROM Drive
1 Sound Card
1 Gigabit LAN Card


Keep in mind, that's only 1.2ghz CPUs. What do you have in it? Also, keep in mind... Watts and amps are not the same thing! You need to make sure that PSU is capable of delivering 30 AMPS on the 5v rail.

Board actually uses Three power connectors: 20-pin ATX, 4-pin auxiliary & 4-pin molex.
Took the board out of the case and dismantled it. One Cpu is definitely smoked. I can see a bubble on the back side of the CPU. Will post pics tomorrow.

[dood]

Re: ATX Connector

Board actually uses Three power connectors: 20-pin ATX, 4-pin auxiliary & 4-pin molex.
Took the board out of the case and dismantled it. One Cpu is definitely smoked. I can see a bubble on the back side of the CPU. Will post pics tomorrow.

Oh, okay. Looking at the picture on Tyan's website, I only saw the main ATX connection. What you say makes a lot more sense!