stangest thing!!!!

[rthompson80819]

This is a real long shot, but when you took the computer into the stores did you take everything including the keyboard, mouse and monitor?  Was there anything different hooked up when you were in the shop?

[Computer_Commando]

You don't need a hard drive at all to see anything on the monitor.  You would see the "hardware startup screen" called the BIOS.  You would see the name of the computer if it were a name brand, i.e. Dell, HP, Compaq, etc.
Some computers have only one light at the power button, but that does indicate it is getting some power, i.e. +5VDC.  Therefore, "hydro" is OK.

There's a bunch of fans & a hard drive, none of them spin or make any noise?
What is the make and model of the offending computer?

No disrespect, but I have the feeling you're missing something, I just can't figure out what.  It's hard to believe it works at the store but not at your home.  Something's gotta be different.  You may have to open it up and look for a loose connection.  It could be that the power button itself is almost broken and the techs at the shop got lucky.  The power button is a momentary close and can be done manually by momentarily shorting the two wires together.

[elitenoob]

  This is similar to my recent problem--my power supply went bad--the fans would power up--motherboard lights etc etc--but i kept getting "no input signal" from the monitor.  Some tech guys told me when a power supply goes bad--thats it, its dead and no power or very very low power would be detected.. They were wrong. Especially with these new power supplies that have several internal power cord slots--one port can go bad and the others work etc etc--it can drive you mad trying to diagnose.

  A word of warning--my power supply ended up frying my motherboard/proc/ and possibly my hard drive. It was a nightmare sorting everything out and finally tracking down the cause. If you have an extra power supply laying around--swap into your system and see if that works. I am not sure on how to actually test a powersupply and see if it is putting out proper current from all the ports etc.

  A possibility is that maybe--maybe while moving it around there is a short in the powersupply and thats why it doesnt/hasnt worked at home.  I hope you find an answer soon, I know it can be very frustrating trying to track a problem like this down--never give up!

[Geek-9pm]

Check the settings on  the monitor. Check the cords.
I have a monitor that I sometimes have to turn on and off a couple of times before it finds the sync from the video card.  And make sure the video card is fully seated. With power off!

[mustanger]

The monitor only shows no signal because the computer is not booting up!!
Today i replaced what i believe is called the BIOS battery-small watch sized battery- turned the computer on and it powered up!!  So monitor, keyboard, mouse everything worked fine- went through some programs and everything worked!! Shut the computer down to put everything back together and when i went to restart it- same problem!! would not boot up-no lights or monitor connection!!
My next step is to replace the power supply in the computer.  Question- the Bios battery-is it like a fuse that would have blown or should it still be OK?  My thinking is it should be OK.  Any other thoughts???

[Allan]

Well, just for the heck of it you should probably try the system at someone else's house just to see..........

[Computer_Commando]

Now this is interesting.  You replaced the BIOS battery and it restarted and functioned 1 time?  When you remove this battery it resets the BIOS to default conditions.  When it starts up the 1st time, it looks for RAM, drives, etc and stores this info in the BIOS CMOS.  No, this battery is not like a fuse.

It's possible that some bad component is preventing the computer from starting.  Remove any add-in cards and the data & power cables from the hard drive, CD-ROM, etc, so the BIOS won't see them.  Remove all RAM except for 1, some mobos won't do anything without some RAM.  Then see if you can just get to the BIOS (setup) screen more than once.  This will prove it's not the motherboard.  Then, by deduction, the culprit is one of the devices you removed.  Start plugging them back in, one at a time, until it fails, and you've found the bad one.

BTW, you can check the BIOS (CMOS) battery with a voltmeter.  It's probably a CR-2032 and is 3.0VDC.  I suspect the old one is just fine.

[mustanger]

thanks for some ideas commando!! I'll give them a try sometime and let u know!! I'm not giving up just yet!!!

[Computer_Commando]

A few years ago, I was given a computer that did the same sort of thing.  Sometimes it would turn on and sometimes it wouldn't.  I was working on it one day, turned it on and there was a blinding flash.  Turned out to be an intermittent short on a high output audio card.  It was then easy to find because of the smell and the burn marks on the card.  Removed the card and never had a problem again.

If there is a short somewhere, the power supply will protect itself by not turning on or turning off immediately.  I suspect you have an intermittent shorted +12V component, which are drives, fans and some motherboard stuff.

[mustanger]

Ok so i unplugged everything i could.  Plugged in cd driver and started it up and all was fine.  Shut it down and unplugged cd driver and plugged in CD writer- started it up and all was fine.  Shut it down and plugged in both and the computer wouldn't start-just got no signal sign on monitor.
So... should i assume that the power supply is weak and not putting out enough power to start everything up???  If so, is it difficult to change the power supply.  I would like to try myself.  Now that i've gone this far i'm finding it kind of fun to play around inside the computer!!!

[patio]

Ok so i unplugged everything i could.  Plugged in cd driver and started it up and all was fine.  Shut it down and unplugged cd driver and plugged in CD writer- started it up and all was fine.  Shut it down and plugged in both and the computer wouldn't start-just got no signal sign on monitor.
So... should i assume that the power supply is weak and not putting out enough power to start everything up???  If so, is it difficult to change the power supply.  I would like to try myself.  Now that i've gone this far i'm finding it kind of fun to play around inside the computer!!!

Borrow a known good PSU of the same wattage or greater and swap it in ther overnite...
You will soon know if that's the issue or not...

PS. Glad yer havin fun inside the case...remeber to remove all power sources and take anti-static precautions....

[Computer_Commando]

That seems kind of odd because it all worked in the shop.  It is indicating a weak PSU, however more testing is in order.  Get a voltmeter and measure the voltage at the receptacle.  I know you're in BC, but all North America is the same.  Should be 120VAC +/- 5V.  If it's below 115, you may have a pole transformer problem.  Most of the PSU's have a very wide input range, but if you're a little low compared to the shop, that may be just enough to account for the difference.

While you're at it, you can easily measure the output voltage of the PSU while it is under load.  Plug in the 2 offfending CD's adn attempt to power it on while watching the meter.  Measure between yellow and black on the power plug.  It should be +12VDC.  Between red and black is +5VDC.