second power supply

[Guest]

I am trying to use a spare power supply as a supplemental power supply. There
is no room in the case for a second power supply so I put it outside the case
and threaded the cables through the back of the computer case then attached
the cables to unattached hard drives. Then, I turned-on the spare, external,
power supple then turned-on the internal power supple but the spare, external
power supple did not turn-on. What should I do?

 

[VanguardLH]

I am trying to use a spare power supply as a supplemental power
supply. There
is no room in the case for a second power supply so I put it outside
the case
and threaded the cables through the back of the computer case then
attached
the cables to unattached hard drives. Then, I turned-on the spare,
external,
power supple then turned-on the internal power supple but the spare,
external
power supple did not turn-on. What should I do?

The PSU won't power on unless the 20-/24-pin connector is attached to
the header on the motherboard. Since you only have one such header on
the motherboard, only 1 PSU can be connected at a time. If you want
dual PSUs then you have to get those that are made to work as such.

 

[John]

I am trying to use a spare power supply as a supplemental power supply. There
is no room in the case for a second power supply so I put it outside the case
and threaded the cables through the back of the computer case then attached
the cables to unattached hard drives. Then, I turned-on the spare, external,
power supple then turned-on the internal power supple but the spare, external
power supple did not turn-on. What should I do?

First of all, what type of PSU is it (AT, ATX or ATX2)? If it is the
most common type of supply (ATX) then it will require pin 14 of the
Molex connector grounding to bring the PSU to life.

John.

 

[Ken Blake, MVP]

I am trying to use a spare power supply as a supplemental power supply. There
is no room in the case for a second power supply so I put it outside the case
and threaded the cables through the back of the computer case then attached
the cables to unattached hard drives. Then, I turned-on the spare, external,
power supple then turned-on the internal power supple but the spare, external
power supple did not turn-on. What should I do?

You didn't say anything about the cables that supply the power *to*
the power supply? Where did you think it was going to get its power
from?

The power normally gets its power from the cables attached to the
motherboard, and there's only room on the motherboard for one power
supply to be connected. I suppose you could jury-rig another way to
get it power, but you didn't say anything about doing that.

 

[Guest]

I thought the 4 pin hard drive power cables coming from the power supple got
power from the power supple so that when I turn-on the power supple, power
goes to the hard drives.
______________________________________________________

 

[John John]

Buy a bigger proper power supply? The circuit has to be completed on
the PS-ON wire if you want the power supply to run. In other words the
switch is off until you complete that circuit, the same as when you
press the on switch on a computer.

John

 

[Guest]

I think its the standard ATX. Its bigger than a micro ATX.

Are you saying that pin 14 of the motherboard connector brings the PSU to
life?
_______________________________________________________

 

[Guest]

I flipped the on-off switch on the external, supplemental, power supple to
on but that power supple did not turn-on. Are you saying that I _ALSO_ must
complete a circuit to get that power supple to turn on?
__________________________________________________________

 

[John John]

Yes, exactly. In a computer the main switch on the power supply is
always on, you don't switch that off when you turn off the computer, you
open the PS-ON circuit (pres the on/off button) and the power supply
turns off. Think of the lights in your living room, when you want to
turn them off you don't go to the main power panel and switch it off,
you flip the light switch. If you throw the main switch from the off to
the on position at the power panel, if the light switch is off in the
living room the lights won't come on, the same deal with the power
supply, you have to close or complete the PS-ON circuit, that is the
equivalent of the light switch in the living room. You can use the main
switch on the power supply if you want but to do so you will have to
close the PS-On wire to the ground wire, do some searching on the net
and you should find out more about the wire assignement for the PS-ON
wire, then stick a wire from it to the ground, or wire it to a small
switch or use alligator clamps to close the circuit.

John

 

[VanguardLH]

I think its the standard ATX. Its bigger than a micro ATX.

Are you saying that pin 14 of the motherboard connector brings the
PSU to
life?

The PSU is never completely powered off if the power cord is plugged
into it. 5VSB (5 volt standby) is still alive from the PSU to power
logic on the motherboard for controlling the PSU. The switch for
Power on the case doesn't go to the PSU. It goes to the motherboard.
Logic on the motherboard decides when the PSU will fully power on. To
do so, the motherboard drops the PS-ON signal to ground which tells
the PSU to fully power on. PS-ON is the green wire (pin 14 for the
20-pin connector).

Put in 1 bigger wattage power supply.

 

[John]

I think its the standard ATX. Its bigger than a micro ATX.

Are you saying that pin 14 of the motherboard connector brings the PSU to
life?
_______________________________________________________

I thought I said that.

John.

 

[Unknown]

I don't believe that is true at all. If it were as you say, power would come
on as soon as it were plugged in.
That is not the case. When the switch is pushed in it provides a start pulse
to the power supply. That requires a
normally open switch. All computer power supplies are 'switch mode' and
require a start pulse.
Also, if true as you say, power would immediately drop as soon as the power
on button was pushed in.
That is not the case. It must be held in for at least four seconds.

 

[Unknown]

The only cable that supplies power to the power supply is the line cord.
The standby power is generated within the supply and in effect is routed
through the power on switch to provide a start pulse for the supply.
Regardless, power supplies, particularly switch mode supplies cannot
be paralleled like batteries.

 

[John John]

Once again, as usual, you don't research anything and you argue about
things you know nothing about. If there is a load on the 5v line (b11's
hard drive provides that) the PSU should start. It wasn't my intentions
to search for b11's project but because it is apparent that you can't
use a search engine I did a quick search and found this:
http://www.nfdc.net/home/cbdb/Teardrop 12 V Power Supply.htm

Now, before you come back with more arguments, I should make it
perfectly clear that I do not endorse b11's idea or recommend that
anyone try what he is doing! He could very well fry his whole computer
with his inventions but that is b11's problems, not mine. If he wants
to "thinker" he will have to do his research and homework. Another
poster in another group (b11 multi-posted to other groups) informed b11
that he may also need a 'power good' signal for the PSU to keep
operating, so maybe he needs to do more that close the PS-ON circuit for
this to work, b11 will have to do his research and find out for himself
what need to be done for his project and tinkering to work as he intends.

John

 

[John John]

More information for you here, b11:

http://www.directron.com/2powersupplies.html

John

 

[Unknown]

Once again you read things into items that are not there. Go back and read
the original post. Notice the OP said he
turned on the spare supply (external) then he turned on the internal.
Doesn't this indicate he is paralleling the internal?
This has absolutely nothing to do with taking a power supply and creating a
'bench tool' out of it.
Once again you tell me I don't research anything. I submit you don't
understand b11's project.
I need not search things YOU don't understand.

 

[Unknown]

Once again as usual you don't understand. How for example is power on/off,
standby, and hibernate incorporated on the on/off switch.

 

[John John]

Well now it is absolutely plainly obvious that your reading and
comprehension skills are limited to say the least. The link I provided
was to show the workings and wiring of the PS-ON mechanism on a PSU and
to counter your argument that more needed to be done than closing the
circuit in question to get the PSU to work. A 7 year old child could
have figured that out and logically adapt the instructions to answer
b11's query. Only a fool would assume that that the information PS-ON
information there applies to a bench tool only and only someone like you
would come back with more silly comments and arguments to the post, it
appears to me that you can't keep anything in context.

John

 

[John John]

Why will that matter? You really should read things twice before you
post! The primary PSU will still controll all of these features, the
second PSU is "supplementary", maybe b11 wants to put a disco ball in
his computer! The other link that I gave to b11 shows how to use more
than one PSU and it gives reasons as to why someone might want to do so.
After I read it and thought about what it is that "moders" do the idea
started making a bit more sense, even though I wouldn't use or recommend
using 2 PSU's I now have a better understanding of why some may want to
do so and it isn't such a far fetched idea after all.

John

 

[Unknown]

MINE? you are the one that posted all the ridiculous comments about the
power on switch. (always on etc) I merely refute that. You seem to get your
jollies off when someone either contests or debates with you on your posts
by changing and twisting things around. Then you throw insults. Who are you
trying to impress? Counter my argument that more needed to be done ????. I
was talking about the on/off switch always being on (that YOU said).
Obvious, as displayed in other posts, you can't read and/or add something
not there.
Talk about context----reread this entire string.
Why are you so defensive and insulting when someone questions you?.