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questions about the green and red light on front of computer.

Posted on 2011-09-05
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I have an older XP machine that had to be replaced due to the symptoms of a bad mother board or hard drive.
I have one program I need to get done with and then I won't need this system again.

It has come on fine the last 4 times I have used it.
When the power button is pressed the green light comes on, and the red light begins to flash = booting.

Today, however, the red light just goes off and on, one time, and that tells me it is not booting up. So, I hold the power button in until it cuts off and the green light goes off. Then I try to boot again and still the red light won't keep blinking.

The holding in of the power button to cut it off, was getting old. So, I just pulled the power cord out from the back.
The green light "stayed on."
Why?
The power has been disconnected.

So, I plug the power cord pack in and the green light goes off and now won't come on at all.  (??)

Holding the power button in until the green light went off, was my way to know it was off, so I could try to turn it on again. Now, my only indicator is the red light.
5-6 attempts and the red light won't stay on, which tells me it is not booting up.

Now, it may start fine tomorrow.

So, what happened with the green light?
Why did it go off when the power cord was plugged back in, and why did the green light stay on when the power cord was removed?

Also, what is the button near the power cord on the back that has a "o" and a "-"
It seems not to affect anything, whether it is on or off.
(o = on ? )
( - = off ?)

revised:
o appears to be off.

Now I notice there is small black push button between the larger silver plated on-off button for the computer. This black button is located above the main on-off button, and below the red light. The green light, which no longer comes on, is above the red light.

What does this small black button do?
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Question by:nickg5
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The green light indicates there is power, and the red one shows hard disk activity.

The mainboard of the PC has capacitors inside, and even when you remove the power cord from the PC, those capacitors can retain some energy for some time, thus the power light doesn't turn off immediately, it takes some time. So if you had waited a little longer the light would have gone off. It probably was just a coincidence that when you reattached the power cord it went off.

The "0" at the back of the powersupply means "off", it has the same effect as pulling the cord. The "1" means "On". If that switch is set to on and you still can't turn the system on via the front power on button, then it is possible that button is broken, or an internal connector has gotten unplugged, or the powersupply is broken, or the mainboard, etc. etc. etc.
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by:Callandor
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You'll need to post pictures for us to see, as the description is difficult to diagnose with different manufacturers.

When you experience intermittent power on problems, they are most likely due to bad capacitors in the power supply, motherboard, or video card.  The usual symptom is cold booting (starting from a long OFF condition) doesn't work, but warm booting (starting soon after the system was turned off) does work.  This being an old machine tends to reinforce this guess.
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by:nickg5
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With the swtich on "1" the green light is no longer coming on at all.
The red light does, but it only blinks one time = no hard disk activity, as you said.

So, why is there no longer a green light?
And there is a red light?

What about the small black push button on the front.
I owned the pc for 4 years and never even knew it was there.

The program I have, can only be run on XP, so this is my only XP system.
It has periodically come on one day and not the next.

Today, though, over 10 attempts and no hard drive activity (via red light) and now the green light won't come on at all. EVEN THOUGH the system is on.
I know this because the only way to get back to the red light is to hold the main button in for 10-15 seconds, which would be an abnornal shutdown.
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by:nickg5
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Here is the view of the silver on-off button,
the small black push in button that I never even noticed were there,
and then the red and green.

The red and green appear to be on, but they are not.

Acer machine, custom built, I have no idea the manufacturer, but the motherboard was Intel, I think.
pc-001.JPG
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by:rindi
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There could be something wrong with the mainboard or powersupply, and as Callandor has suggested, bad Capacitors are likely suspects.

Without knowing what PC make/model it is, it's difficult to say what the other button is for, but on many PC's there is a "reset" button, which is used to hard reboot the PC.
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by:nickg5
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rindi:
what do you mean by "hard" reboot?

I have not used the pc in a couple weeks, but the temperature around the system has been in the low to mid 80 degree range, so it may be a "cold booting," but the parts have not been subjected to any cold temperatures.

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by:nickg5
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It was custon built so make and model is not known and the shop that built it is gone.

The system I am using now, has a huge power button, green on the right, red on the left and what appears to be a smaller black button, at the bottom which may be the reset button. So both machines appear to have a reset button.

How can I know if the reset button is, on or off?
(or does it matter, maybe it's on when preseed in and off when released)

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by:rindi
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A hard reboot is when the system won't power down or reboot the normal way (by using either the windows shutdown / reboot menu, or the front power off button).
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by:nickg5
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I removed the cover. With the power cord plugged in, there is a green light on, on the mother board. This light stays on continuously, as long as the power cord is plugged in. Once unplugged, the green light blinks and slowly, over a period of maybe 15 seconds, goes dimmer and dimmer and finally off.

Plug it back in and the light comes back on.
--------------------------------------------------------------------------------------
No green power light on the front.
Red light comes on but then off so no activity.

I had 100 sheets to print using this specific program. I got 93 of them done.
I guess the rest are trash unless this system boots up tomorrow or next week, though time goes by and by = colder boot (?)
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by:Callandor
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The green led on the front is the power led indicator, as rindi said, but it sounds like it is malfunctioning (or the connector is loose), since you are getting hard disk activity (red led) with the green led unlit.  It is normal for the red led to flash; it is not normal for the green led to not be lit if your computer is on.

Cold boot, by the way, has nothing to do with the ambient temperature - it just means the system has started from a completely off state.
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by:nickg5
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So the red light on, means the system is on, and getting power?

This pc was off for over a year, before I began to install this program to print these 100 pages. So, being off the last 2-3 weeks did not prepare me, for, no boot.



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by:wrenhal
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The Red blink with no green light on the front means the power supply is bad or there are bad capacitors on the motherboard.  Both these possibilities give off the same symptoms.  Also, the green light on the motherboard itself would continue to light up under either circumstance.  You can inspect the motherboard for items similar to this:  Leaking capacitors  or this:  Bulging capacitors .  If you have neither of these anywhere on the motherboard then the next step is to go ahead and replace the power supply.  If you see these bad capacitors then the motherboard is most likely dead and needs replacing.
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by:Callandor
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The red led is the hard drive, as rindi stated.  The green led is the power indicator, but the pc seems to be powered on, even though the green led does not indicate it (the hard drive cannot run without power, and it clearly is running).
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I'll assume the role of the least knowledgable.

Callander:
So, my hard drive is running, because the red light comes on?
(even though it won't boot up)

And for the red light to come on, that means the power supply is good?

Here are the steps done today.
I attempted to turn on the computer, but it would not bootup. I could tell  because the red light would blink once, and go off. After trying 3-4 times, I thought the quickest way to turn it off and on, would be to unplug the power cord.
THIS is the exact point, at which, the green led on the front of the computer stayed on, and happened to go off, it seems coincidentally, as I was re-attatching the power cord to the back of the computer.
From that point, on the green led on the front never came back on.
But, the red light did and would never boot up.

We have a shop nearby that will diagnose for no charge.
The project is not worth the cost of a used power supply, etc.

I can remove the power cord and inspect the mother board myself.
Is there anything in there like there is with a monitor or a television?
Anything to not touch, or get near?
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by:Callandor
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The red light is an indication of hard drive activity.  It does not mean your power supply is good; only that it has enough power to do something.  Your power supply could be sporadic and give the impression that it is supplying normal power.

The motherboard is safe to inspect - nothing higher than 12v goes to it, and the capacitors are small, so they don't hold a dangerous charge.  Keep in mind that capacitors can look perfectly normal and not work, but if they are bulging or oozing brown stuff, they are probably bad.  www.badcaps.net is another source of information on bad capacitors.
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by:nickg5
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I see no bad capacitors.

This system would over heat "only" when I was watching 5+ minute videos.
The repair shop installed a 2nd fan that kept a specific part, from over heating.
The fan was mounted directly over the part.

So, this motherboard and power supply were deemed good, at that time.
It slowly, with very little usage, started to bootup, or not bootup.

I'll try turning it on once a day for 2-3 weeks and then assume it won't ever come on again.
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by:nobus
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most probably you are suffering from bad capacitors - as said
the fact you don't see one, does not mean they are ok, note that may be INSIDE the power supply also
easiest is to hook up another PS to test
here's how bad ones look
caps.jpg
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by:Insignificant Volunteer
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Did your computer used to make a beep on successful boot?

Is the monitor light changing from amber to green at any time when you try to power up the PC?

You say that the PC wasn't used for a year or so.  Did you maybe give it a bump when you took it out of a closet or when you were connecting it all up again?

Just wondering if one of the connectors that joins the wires from the front panel (power switch, lights, etc) to the motherboard may have an intermittent connection after being bumped heavily OR if you perhaps dislodged a wire if you pulled off the front panel to blow dust out before firing her back up again.

At one of the edges of the motherboard you will see connectors something like the image below where the thin (often twisted) wires coming through a hole in the front side of the metal chassis have thin plastic connectors that go over thin gold pins:
http://duhvoodooman.com/mitchedo/Dell/panelconnected.jpg
http://img.tomshardware.com/us/2002/09/18/building_your_own_pc/panel_leitungen.jpg

Look and see if any of the connectors are sitting up higher than the rest.

Being right at the edge of the board, they are often crammed right up against the inside of the case and are a real pig to reconnect with the correct pins while the  motherboard is still in the case if one is accidentally tugged off, so if you see one sitting up higher than the rest and try to push it down be VERY careful.  Use a toothpick or something.

Avoid touching the motherboard components with your hands (or feet for that matter ;-) because we all emit static electrical charges that can damage the chips.

I tend to think along the lines of what the other experts are leaning towards, ie. bad power supply unit probably caused by bad capacitors inside it.
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by:nickg5
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Let me look closer. I saw no bulging capacitors or leaking ones, based on the photos.

Would it do harm to tap on each capacitor with the butt of a small screw driver?

There are some cables inside that are not hooked up. I'll post a photo.
The shop did a full test on hard drive, etc. and these long digital videos were causing a part to over heat, and shut the system down like a light switch.
They installed a special fan over this part.

Let me post a couple photos.
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by:nobus
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>>  Would it do harm to tap on each capacitor with the butt of a small screw driver?  <<  no , but i don't see what you want to achieve with it (unless one calls out a 4 letter word at you..)

 
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by:nickg5
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I've got a TV whose picture gets smaller, top to bottom. I tap on the sides of the TV and it works fine for weeks and weeks.

When this PC is headed for the trash unless it bootups up again, I was reaching into the sky for a stroke of luck, and tapping the capacitors might get any bad one, to work a couple more times. I know the chances are 0.01%.
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by:nobus
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>>  I tap on the sides of the TV and it works fine for weeks and weeks  <<  bad contacts - best resolder the place where it reacts most
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by:Insignificant Volunteer
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Nick, it seems you now have a screwdriver in your hand.  Please ** DO NOT ** take the "TV" (Monitor) to pieces OR take the computer's Power Supply Unit apart:
http://tech.blorge.com/wp-content/uploads/2009/01/power-supply-1.jpg

There is a lot of power stored inside them for a long time AFTER they are switched OFF and it can kill you - or at least throw you across the room and give you a hairstyle like Brian May!!
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Someone said there were capacitors to inspect inside the power supply.

The small fan in that photo looks like the one the repair shop installed to control my overheating.

I'll check the board for any loose connections, since the thing I lost first, was the green LED on the front. Coincidentally it went off, for good, and all I did was unplug the power court, instead of holding in the on-off button on the front.

Any fuses?

Seems a little curious that the green light dies, upon pulling the power cord from the back of the computer.
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by:Callandor
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Coincidence - there shouldn't be any correlation.  Tapping bulging capacitors doesn't fix them; once they've gone bad, they're gone (typically the electrolyte solution inside has turned to gas).
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by:nobus
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>>  Someone said there were capacitors to inspect inside the power supply.   <<   for inspecting them, all you need to do is remove the cover of the PS - (4 screws) and look at it; so there is no danger involved
for replacing them - yes then you need to be careful; but if you unload the 2 big capacitors by shorting them (gives a flash) all possible harm is gone also
   
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I think I'll take the computer to the shop and get a free diagnosis.

Symptom is the green light stopped coming, on but the red light does, and let them run their test.

I looked in there again, and the system has not been moved, etc. so no loose wires, etc. I'm getting the same result day after day, red light blinks once, green LED on the front won't come on.

They will easiliy be able to hook this up, to a good power supply and see what happens.
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by:nobus
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good luck
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by:nickg5
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Repair shop says power supply.
I think he said a "450" (?)
So, luck on the motherboard, etc. being good.

I watched the event.
The red light came on and stayed on, and the green light never came on.
I asked about that and he said the green light did not come on, because he did not have the hard drive hooked up.

New power supply and labor is $40 + $20.
I doubt the project I had to complete, is worth that, unless I want to have the computer as a working spare.
Maybe a used power supply locally on Craigslist.

So, let me go back to the top and look for power supply being mentioned.
And close the question.

Anyone want to throw out anything, about my search for a used power supply?
Just search for the exact model I have?
Easy installation by me? (looked like a few screws and a couple wires)

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by:Callandor
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You can buy one and install it yourself - the supply is held in place by 4 screws in the back, and you just disconnect everything it is connected to.  You didn't mention the manufacturer, and you might get a better deal buying a different one on sale, or a used one that someone wants to get rid of.  New power supplies can go for $20 for a low-powered machine, if you know where to look.

I think the power and hard drive lights are switched, since green is typically used for power and red for the hard drive.  It's not important to get it right, in any case.
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by:nobus
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he mentioned a 450 W because that is what is currently sold
you can look what power supply is in there; probably 300 W or even lower
these can be found cheap in any old PC now
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by:Insignificant Volunteer
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You will get a new boxed Power Supply on eBay for the same or less than the technician would charge, and save the $40 labour.  Actually, those rates are quite reasonable.  He could have quoted more, but obviously realised that you were deciding if the cost was worth it.

Look at all the cables from your current power supply and where they connect to the motherboard.  All power supplies will have a long rectangular connector:
http://www.karbosguide.com/books/pcarchitecture/images/979.jpg
http://www.pcfixzone.co.uk/images/MB08.jpg

Pentium 4 processors also need the additional square 4-pin one:
http://stuff.h-i-r.net/blogstuff/pstest-2.jpg
http://computershopper.com/images/tips08/55.jpg

I highly doubt whether your computer is new enough to have SATA drives, and so should have the wide flat "rubbon cables" connecting hard drives/cd to motherboard rather than the thin SATA connectors.  I'm pretty sure it will not have any PCI-E slots either.  In that case you don't need a Power supply with either the PCI-E 6-pin connector OR the SATA connectors as shown here:
http://morechristlike.com/blog/wp-content/uploads/2011/03/power-connectors-atx.jpg

The "Molex" connectors in the image are the ones that connect to your hard drive(s) and CD- drives, and the Floppy connector is self-explanatory.

If you have a Pentium 4 computer, then you will need an ATX "Pentium 4 ready" power supply with the 4-pin connector.  Most new and boxed older spec ATX Power Supplies will have a Pentium 4 connector just in case it is needed.

To remove the old power supply and fit the new one you MAY have to remove your CD or DVD drive at the top, and possibly also your memory sticks, depending on where they are placed and how much space you have inside the chassis.  If removing ANY components, make notes of where they came from and ONLY handle the memory sticks by their edges if you need to remove them.

This is actually a very good video if you can overlook the advert at the start, the young man's mo-no-to-nous voice, horse's ass hairstyle, and the missing "h" from words like "here" and "have":
http://www.videojug.com/film/how-to-install-or-change-my-computers-power-supply
Just concentrate on what he is doing.

Go to YouTube and search for "how to fit install a new power supply".  You will get loads of videos showing the various layouts of different PCs.  Compare them to your own layout and watch a few times to get the idea in your head then it should be very simple.

Take a note of what the label says on your current power supply and post them here if you need any help once you find what you think is a suitable one.
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by:nickg5
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Broken power supply was first mentioned by the first responder, rindi.
And that was the culprit, the power supply.
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by:Insignificant Volunteer
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Thank you Nick, and good luck with getting your PC fixed and finishing your project.
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