Booting Machine

[John Leddy]

I always started my system by:



1. Turning on the switched surge protector which started the monitor

2. Pressing the start button on the front of the computer



The machine would then boot.



I replaced the old power supply with a new one that has a rocker on off
switch and I am now having trouble. To start the same way as before, I now
have to turn the power supply rocker switch on and off a few times to get
the machine to boot. Once started, all is fine. I also now have to do the
same thing to get the machine to wake up when in the sleep mode.



It has been recommended that I replace the power supply, but everything
works fine after the system boots.



Before I replace the power supply, I would like to know if there is a
procedure to start a system with a power supply that has a rocker on and off
switch.

 

[Blinky the Shark]

Before I replace the power supply, I would like to know if there is a
procedure to start a system with a power supply that has a rocker on and off
switch.

Yes. Leave the PS switch on. Turn the computer on/off with its
On/Off switch.

 

[Michael Hawes]

I always started my system by:



1. Turning on the switched surge protector which started the monitor

2. Pressing the start button on the front of the computer



The machine would then boot.



I replaced the old power supply with a new one that has a rocker on off
switch and I am now having trouble. To start the same way as before, I
now have to turn the power supply rocker switch on and off a few times to
get the machine to boot. Once started, all is fine. I also now have to
do the same thing to get the machine to wake up when in the sleep mode.



It has been recommended that I replace the power supply, but everything
works fine after the system boots.



Before I replace the power supply, I would like to know if there is a
procedure to start a system with a power supply that has a rocker on and
off switch.

Rocker switch is NOT your problem. Why did you replace the PSU? What
make/model is new supply? What was original make/model? There are a lot of
cheap rubbish PSUs out there. Switching on PSU experiences power surges
from various items which cause problems to faulty/crap PSUs, thats why it's
OK when it DOES manage to start. The fact that you have to flip the rocker
switch shows that the PSU is tripping out at power on.

Mike.

 

[John Leddy]

Mike:

I have an older emachines of which I added a graphics card and an audio
card. I felt that the original power supply wouldn't be adequate along with
an additional hard drive.

I installed what I thought was a quality new power supply. I installed a
MGE XG Vortec 600 Watt Power supply and it is supposed to have a lifetime
warranty. I don't know about the company as I haven't received the rebate
yet!

If you suggest, I will reinstall the old emachines power supply (250 watts)
and see what happens.

Thanks for the help!
John

 

[Paul]

Mike:

I have an older emachines of which I added a graphics card and an audio
card. I felt that the original power supply wouldn't be adequate along with
an additional hard drive.

I installed what I thought was a quality new power supply. I installed a
MGE XG Vortec 600 Watt Power supply and it is supposed to have a lifetime
warranty. I don't know about the company as I haven't received the rebate
yet!

If you suggest, I will reinstall the old emachines power supply (250 watts)
and see what happens.

Thanks for the help!
John

At the very least, do not quickly alternate the toggle switch on the back
of an ATX supply. The switch on the back of the supply is not intended
for that kind of operation.

To see why, take a look at this power supply schematic. You will only
need to look at a very small section, to see the nature of the problem.

http://www.pavouk.org/hw/en_atxps.html

NTCR1, in the upper left hand corner of the schematic, is called an
"inrush limiter". It is a thermistor device. That particular one,
when it is cold, it has a high resistance. When the thermistor gets
hot (from self-heating after powerup), the resistance drops to a lower
value.

When the resistance is high, when the power supply is cold, NTCR1 limits
the amount of current charging C5 and C6, the main primary side capacitors.
Limiting the current, helps protect D21,D22,D23,D24, the bridge rectifier.
When you see the lights flicker in your computer room, that is
because of the huge current flow into C5 and C6.

Now, if you rapidly toggle the power switch on and off, NTCR1 is already
hot, and its resistance is low. Much greater currents now flow into the
supply, into C5 and C6. The diodes D21,D22,D23,D24 could be damaged, after
enough repetitions.

In other words, if you switch off an ATX supply, you should wait a number
of seconds, until NTCR1 cools off a bit, before flipping the switch on
again.

An ATX supply is supposed to be "switched" on and off, via the power
button on the front of your computer. Figure out why that is not
happening, rather than torturing the power supply. Otherwise, you
could be in for an expensive lesson (like a fried computer).

If you feel the need to switch the monitor on and off using a power
strip, connect a separate power strip between the monitor and your
main power strip. That way, you can leave the Emachine's new power
supply always "ON" at the back, then use the front power button on the
front of the computer to turn it on and off. PS_ON is what the motherboard
uses to turn an ATX supply on and off. The PS_ON method is not stressful,
like that toggle switch on the back is.

<---------- Main_Surge_Protected_Strip <------ second_strip <--- monitor
|
|"ON"
ATX_PSU_in_Emachine
|
| (PS_ON signal, main power cable)
|
Motherboard
|
Front_Power_Button

Paul

 

[Frank McCoy]

At the very least, do not quickly alternate the toggle switch on the back
of an ATX supply. The switch on the back of the supply is not intended
for that kind of operation.

To see why, take a look at this power supply schematic. You will only
need to look at a very small section, to see the nature of the problem.

http://www.pavouk.org/hw/en_atxps.html

NTCR1, in the upper left hand corner of the schematic, is called an
"inrush limiter". It is a thermistor device. That particular one,
when it is cold, it has a high resistance. When the thermistor gets
hot (from self-heating after powerup), the resistance drops to a lower
value.

When the resistance is high, when the power supply is cold, NTCR1 limits
the amount of current charging C5 and C6, the main primary side capacitors.
Limiting the current, helps protect D21,D22,D23,D24, the bridge rectifier.
When you see the lights flicker in your computer room, that is
because of the huge current flow into C5 and C6.

Now, if you rapidly toggle the power switch on and off, NTCR1 is already
hot, and its resistance is low. Much greater currents now flow into the
supply, into C5 and C6. The diodes D21,D22,D23,D24 could be damaged, after
enough repetitions.

In other words, if you switch off an ATX supply, you should wait a number
of seconds, until NTCR1 cools off a bit, before flipping the switch on
again.

An ATX supply is supposed to be "switched" on and off, via the power
button on the front of your computer. Figure out why that is not
happening, rather than torturing the power supply. Otherwise, you
could be in for an expensive lesson (like a fried computer).

If you feel the need to switch the monitor on and off using a power
strip, connect a separate power strip between the monitor and your
main power strip. That way, you can leave the Emachine's new power
supply always "ON" at the back, then use the front power button on the
front of the computer to turn it on and off. PS_ON is what the motherboard
uses to turn an ATX supply on and off. The PS_ON method is not stressful,
like that toggle switch on the back is.

<---------- Main_Surge_Protected_Strip <------ second_strip <--- monitor
|
|"ON"
ATX_PSU_in_Emachine
|
| (PS_ON signal, main power cable)
|
Motherboard
|
Front_Power_Button

Paul

A thought:
Once running, go into the BIOS and see if there's an option about
booting when powering up instead of hitting the power switch.

 

[w_tom]

I have an older emachines of which I added a graphics card and an audio
card. I felt that the original power supply wouldn't be adequate along with
an additional hard drive.

So you replaced a perfectly good power supply only on speculation.
You can learn why the new supply does not work right OR put the old
supply in and learn (using numbers) whether it is sufficient. Either
way, you need a $20 multimeter and a two minute procedure previously
posted in "When your computer dies without warning....." starting 6
Feb 2007 in the newsgroup alt.windows-xp at:
http://tinyurl.com/yvf9vh

Simply access all peripherals simultaneously (multitask) including
complicated graphics on display. Then measure voltages on the orange,
red, purple, and yellow wires. Voltages must exceed numbers provided
in that post. Also post those numbers here for other useful
information.

How large is that original power supply? Well at 250 watts, then it
may have been rated by the 'clone' power supply industry at 360
watts. This happens when the market is computer assemblers who don't
even know how electricity works. Instead of using their speculation,
measure what you really had.

Why a power supply so massively large (600 watts)? Did you
understand the Tim Allen joke in Home Improvement about "more power"?

First know what you have before fixing what may not be broke. Meter
can also show you why a new power supply 'does not power on first
time'.

 

[John Leddy]

I installed the old power supply and all works perfectly. The new power
supply was defective!
John

 

[w_tom]

I installed the old power supply and all works perfectly. The new power
supply was defective!

First defective could be the power supply controller. That original
power supply corrected the defect. Second, until you have takes
voltage readings with the multimter, you still don't know if the
original supply is sufficient. A defective or undersized power supply
can appear just fine for months when numbers on the meter demonstrate
a problem that results in intermittent failures months later. There
is no way around numbers from that multimeter if quality and
reliability is an objective.

Second, your test does not say a new supply is defective. It says a
new supply is incompatalbe with other parts of the power supply
'system'. How? Why? Just another reason why we fix things ourselves
- to also learn WHY things fail. Your post provided no reasons to
proclaim the new supply as defective because conclusions are based
only in shotgun observations.