FRIHOSTFORUMSSEARCHFAQTOSBLOGSCOMPETITIONS
You are invited to Log in or Register a free Frihost Account!


Nobody can explain this!





ocalhoun
I challenge you to explain this:
Read this entire post before replying!
I know its a lot to read, but it really is needed for proper understanding.

background info:
I have a "normal" desktop system (Okay, I've made a lot of modifications and it is very quirky)
I have 2 power supplies (one added on later, using a dremel tool and duct tape), but this problem predates the second power supply.
The power supply that does this is an ATX (the other is an AT)
The wiring in my house is perfectly normal 120v ac.
I live in Polk county, Florida (lightning capitol of the world).
I have a surge protector, but no UPS.
BIOS is set: power status after loss of power:<off>

The problem:
This is the only sequence of events that will cause the problem:
1) the computer is running normally
2) There is a power outage
3) Attempted reboot within a few days
this is what happens:
The computer will not boot
The power switch does absolutely nothing

Trouble shooting:
The only way the computer can then be made to work is:
1) unplug the power cable
2) switch it with another cable
This seems simple, but consider these odd facts:
1) if this happens again, switching back to the original power cord will make it work
2) unpluging the power cord and plugging the same one back in will not make it work
3) this happens predictably, and will occur every time the computer looses power when running
4) this does not happen if the power goes out while the computer is off

So, what is going on?
(I'm a computer geek, and expecially good at hardware problems: You can dismiss simple explanations.)
hodgenpodg
have you tried another power supply altogether, and I sure hope you have a good surge protector if you loose power and get lightning strikes that often.
toshlad
Can you explain the power supply config again as I don't really understand why you have 2 PSUs on a standard desktop PC?

How are they connected to the motherboard?

The only explanation I can come to with your current post is that your PSU is cutting out via some sort of internal surge protection that resets after the re-insertion of a power cord (also known as the ICD lead).

When you insert a power cord, you yourself know there is a slight arcing when it contacts with the pins, maybe this is enough to reset whatever it is that is causing it to die?

I hope this helps.
ruff_ryder
Yup, my vote goes for the PSU as well. Try switching it with a different one and see if the problem persists.
ocalhoun
The power supply works fine, as long as it dosen't loose power, so I'm not going to replace it.

For your information, this is how I have 2 power supplies in my case:
One is my original, which is connected to the motherboard.
The other I put in myself here's how:

1) Make sure it is a big case (so it will have enough room)
2) cut a proper shaped hole in the back of the case (yes this involves some metalworking)
3) drill the screw-holes in the back of the case
4) put the new power supply in the right spot and screw it in (it should be an AT power supply)
5) I wired the power switch to a normal wall-socket type switch (its an AT, so this is easy enough if you have a multimeter and the intelligence to reverse-engineer it) MAKE SURE IT IS CONNECTED RIGHT, or it will destroy the power supply
6) I cut a hole in a 3 1/2'' drive bay cover to fit the switch
7) I used epoxy glue to attach the switch to the drive bay cover
8) I connected the power supply to the surplus drives and accessories that I use
9) Installation is complete

Tips:
1) always turn on the second power supply first.
2) remove the motherboard and drives before cutting the case: this prevents metal shavings from getting on them.
eliasr
well since it lose power, 1 eider your power as home , or because the power suply id done, finish, damaged, death. destroyed. bombed, broken, nuked, or ****** up

i had one power suply, it did the same, why, because something was damaged in it (ok, it was normaly running in over a week before i did reset...reset, i sdid not give it a break) well i got my garenty and did fix the problem by changeing the power suply...

since you got 2, will it maybe be a bit hard to find the right one to replace, maybe shall they both replaces.

go to the shop where you got it, say it dont work ,and get 2 new or something. its up to you, but, its the only suggestion as i can see

even that you say there nothing is worng with them, then will i just tell you, you cant see if a konverter is burned out in it, you cant just look after broken components in side the power suply.

it could also be a broken connection in the stick

ust to make fun of it, maybe its connected wrong.
Donutey
Surge protectors especially cheaper ones, often fail over time (repeated surges burn out the mosfets) and it's often impossible to tell by the end user, until equipment is damaged. It might be a good idea to buy a new protector, preferably with indication when it fails (led or such). or a UPS... though with dual PSUs it'll be expensive...
roko
I agree with the surge protector being more issue here...some dont live up to the depands...and specially if u having repeated surges. Only other option would feel remanent static that u might try dispensing...
izcool
There's a few things that I think might be causing it.

My suggestion is to get a few splitters to get your additional devices hooked up with power instead of using 2 separate PSU's.

How exactly are you getting the 2nd PSU to fire up since one can be connected to the motherboard at a time ?

The other possibility is that your home wiring isn't able to accept such of a load with the power. If you have a lot of things plugged into a wall socket, then try taking some of those out to see if that would solve it. I don't think 2 PSU's is normal in a PC. In servers I think it's common, for if one PSU would die, it would kick in off the other.

- Mike.
Clergy
Just make a UPS with a 12-volt car or small vehicle battery hooked up to a slow-drip charger. To the battery, hook up a $2 vehicle accessory socket (i.e. cigarette lighter socket). Grab a 150-watt inverter, plug in a power-strip.

Voila. Power goes out? No problem.
Kestrel
One question... why are you using two PSUs? For just a normal desktop PC they are not needed, really, unless you have a ton of things running, along with internal case modifications (neon lights, extra fans, etc). What I would do is just use one, see if it has a problem. If it does, replace it. If it doesn't use JUST the other one to see if IT has a problem. You could always go to your computer manufacturer and ask them for assistance. Though they will probably say that they are unable to help you since you tampered with the original PC configuration. But it's worth a shot. Wink
ocalhoun
I have 2 PSU's running because if everything I have in my computer was hooked up to the first one, it would blow. I have already lost one internal power cable this way.

By the way, I know its the power supply or the surge protector or something, but how does it know that the power cord has been replaced and not just reseated?
ChunkyBustout
Now, you said this problems pre-dates the addition of the second power supply so I would say either the cords you use aren't identical or one of them is is not quite up to snuff even though it works.

Try testing each lead with a multimeter to check on resistance. I'll bet you find different readings for each cable even if they are identical. This is one way how your PS would "know" the cable has changed. In any case, I would suggest you get a ups with line conditioning. A new power supply would hurt either (just to keep power-related issues from arising).
Arnie
izcool wrote:
How exactly are you getting the 2nd PSU to fire up since one can be connected to the motherboard at a time ?
He already said that: the 2nd PSU is AT. And AT doesn't start via the motherboard like ATX does. It has a direct power switch. I use old AT PSUs for stuff like stand-alone CD players - simply a PSU, powerbutton, CD-drive and headphones.
Clergy
ocalhoun wrote:
I have 2 PSU's running because if everything I have in my computer was hooked up to the first one, it would blow. I have already lost one internal power cable this way.

By the way, I know its the power supply or the surge protector or something, but how does it know that the power cord has been replaced and not just reseated?


I just use a 500+W PS.
ocalhoun
Clergy wrote:
I just use a 500+W PS.

300W + 250 W = 550W
What's wrong with doing it the cheap way?

... should have just made a thread about dual power supplies first.
Clergy
ocalhoun wrote:
Clergy wrote:
I just use a 500+W PS.

300W + 250 W = 550W
What's wrong with doing it the cheap way?

... should have just made a thread about dual power supplies first.


hehe.. fair enough.
izcool
Well doing it the cheap way isn't always the best way of doing it. Although it's cutting corners and generating more heat, getting a power supply with more wattages may be able to handle all of the power that your system is taking when it's running.

- Mike.
Arnie
Why would you throw away a good old AT PSU ánd your old, weak ATX PSU to then buy a stronger PSU? That's triple wasting: you're throwing away 2 that you could use and buying 1 that you don't need. I think it's really cool what this guy did, he's recycling old hardware that's still usable.
izcool
Arnie wrote:
Why would you throw away a good old AT PSU ánd your old, weak ATX PSU to then buy a stronger PSU? That's triple wasting: you're throwing away 2 that you could use and buying 1 that you don't need. I think it's really cool what this guy did, he's recycling old hardware that's still usable.


I never said that he should throw it away (as in the garbage) but I would just recommend buying a much more powerful PSU for it to power all of the things in his computer. Rolling Eyes That's all.

- Mike.
Neo7
My computer sometimes does this.

To solve it:

1. If you have a "master power switch" (like the one on the normal PS2), then switch it to off for 15 seconds and switch it back on

OR

2. Unplug your machine for 15 seconds and replug it in. Make sure that your computer is off.

OR

3. Move to another outlit.
johanfh
When I read your question about the cable I guess there can be different problems (and I know you are a geek and stuff Wink ):
1. There is something wrong with your PU: when you switch the power cable that takes some time. That time is enough to fix the problem (unload a condensator, cool something down like a spool wich gets overheated by the lightining or something else like that. A problem inside wich stays there if the machine is connected to the poweroutlet). You can try this by taking of the powercable, putting it somewhere away, don't use the computer for an quarter of an hour and replug it. If the problem persists it really is something in the cable.
2. In that case there is something wrong with your cable. Maybe it has a greater resistance than the other one or something like that or it has a leak.
3. Other case: if the powercable is broken it could be that it's getting to warm and then the resistance of the cable becomes lower. Maybe there comes a powerconnection inside the cable (I don't now the english word, a powerleak or something) that goes away when the cable cooles down. You could test that by directly taking the cable and use it to boot another pc.

Succes and let us know the solution!
JohanFH
grantmaster
In my experience as a computer technician...

The reason a PC won't power on is because there is a short somewhere.

It doesn't necessarily have to be in the power supply. I've seen shorted modems (from power spikes and outages), video cards, etc. cause the computer not to start.

If it were me I would go get a brand new, good quality power supply and power cable, and plug that in to a good surge protector. Not a power strip but a surge protector with a fuse, maybe even two. It is after all "the lightning capitol".

If it still continues then it is probably a damaged expansion card or even motherboard...
paul_indo
I used to run a 2 PSU's like you are because I have a lot of Hard drives and CD/DVD drives a CD writer and a DVD writer plus extra fans.

I also had similar problems to yours and I thought fo a long time that it was something wrong with my PSU's.

Eventualy I bought a UPS and ALL my problems went away.

I have since replaced my PC with a newer system but I will always us a UPS for the rest of my life.

Electronic components don't like surges or cuts to their power and this can cause all sorts of weird problems. A UPS can eliminate this possability.
Related topics
Reply to topic    Frihost Forum Index -> Computers -> Computer Problems and Support

FRIHOST HOME | FAQ | TOS | ABOUT US | CONTACT US | SITE MAP
© 2005-2011 Frihost, forums powered by phpBB.