Another Power Supply Question

[lemonyx]

Hi guy's,

I've gone thru these two links: http://www.procooling.com/index.php?...s&disp=52&pg=2 and http://www.antennex.com/preview/archive3/powers.htm and have modded my two PC PS's.

I'm sure I have missed this, but what do you do with the black "switch" cord
(it's that cord on the right of the bunddled wires) do you just leave it or do you cut it off? There was a mention to wire the PS up together for power, I guess I can use this cable to do that. I would assume that I just keep the connections the same.


*Note: Most PC Power Supplies have an ORANGE wire that provides the "Power Good" signal back to the supply. Tie this wire to the +5 VDC leads. Not all supplies have this feature, however, the supply will provide no output voltages without seeing a positive going 5 v signal on this line.

With this orange"sense" wire connected to the +5v will I still need the resistor? On the interface and driver bd's, would that be enough of a load to not have to use the resistor across the +5v and gnd? (will be using Paul's 4 axis interface and the picstep's for drivers)


we must connect the 1 or 2 ohm resistors I mentioned in the supplies list across the +5 volt connections. In other words, one end of the resistor must go to one of the red (+5v) wires and the other end of the resistor must go to one of the black wires (negative). The reason we must do this is that to ensure the power supplies provide a nice clean supply of current, the +5 volt section must have a load placed on it at startup. If you do not do this, the power supplies will not function correctly


I'm not an EE by any means, but I use to layout PCB's for a living back in Cali.
My easy question just got complicated - sorry guy's.

Tia

[davesaudio]

Tell us something more about these power supples,
they sound like AT units (200-250w?) from 286-386 units not ATX?
I don't remember any ATX units with hardwired AC side switches but I could be wrong.
If they are are AT then you only need the minimum resistor load on 5V.

You can cut those wires short and connect them inside if you don't want to control them from the existing switches. Usually a double pole-double throw-switch, wires are brown blue black white? IIRC.

[davesaudio]

caution-some units like Dell did not follow convention on pinouts and colour
show us the label under the voltmeter and tell us the colours

[lemonyx]

They are AT's. The pix if from one of the site used for reference. But has that same cable to the right of the colored wires. It went to the front of the PC case that I salvaged the PS from -for power on/off. No these are not Dell's.

The colors are yellow +12, red +5, white and blue which have been cut, black gnd or common and orange, the sense wire.

I will post a pix when I get home of the PS that I have.

[davesaudio]

Took a peek at one I have here:
inside the black power cable- black and white go to the connector where the AC power cord plugs in, so this is the source.
If you have a meter you can confirm via continuity yours is the same.
The switch connects the
black to brown
white to blue
when switched on

does that fit what you have?

[davesaudio]

from the linked article:
*Note: Most PC Power Supplies have an ORANGE wire that provides the "Power Good" signal back to the supply. Tie this wire to the +5 VDC leads. Not all supplies have this feature, however, the supply will provide no output voltages without seeing a positive going 5 v signal on this line.

WRONG

http://www.epanorama.net/links/psu_computer.html

Most but not all require a load on +5V to regulate properly, a few require aload on +12 as well. PWR_OK signal has nothing to do on ther controlling of ATX power supply operation. PWR_OK is an output from the supply. "PWR_OK is a "power good" signal. It should be asserted high by the power supply to indicate that the +12 VDC, +5VDC, and +3.3VDC outputs are above the undervoltage thresholds.

now, for ATX:
To activate ATX power supply, only PS_ON is needed. PS_ON can be activated by connecting ATX power output pin 14 (PS_ON) to pint 15 (ground).

[lemonyx]

Took a peek at one I have here:
inside the black power cable- black and white go to the connector where the AC power cord plugs in, so this is the source.
If you have a meter you can confirm via continuity yours is the same.
The switch connects the
black to brown
white to blue
when switched on
does that fit what you have?

Yep, that's what I have
Thanks for the link -







This switch is the same on both PS's

[lemonyx]

Well, I guess now I'm screwed. Since I have cut the connectors off, I don't know which is/was pin 14.

[davesaudio]

If I can see correctly yours is reversed?
the cord plugs into the lower (closer to the pcb) connector which is blue and brown?
white and black are on the switched side going to the aux connector -(female) then to the psu pcb?

[davesaudio]

I suspect this a simple AT supply and you don't need the orange - just tape it up
yellow and red and black are standard.

[davesaudio]

checking my notes- this is pretty much the definitive link for connectors colour codes etc
http://www.pcguide.com/ref/power/sup...erboard-c.html

[lemonyx]

Forgot to include this



But you are correct the main power plug is on the bottom. Simple AT PS. So you think it'll still startup without the sense wire? But I'll still need the resistors, right? Across +5 I assume??


Thanks for your help.