[electrochimp]

HP a1747c desktop doesn't turn on or show any signs of life when button is pushed. green light is on near power plug inlet. Unit was working fine. just went to turn it on after it was off just a few hours and no response at all. monitor shows "no signal" when monitor switched on/off.

thank you

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I told my wife this the other day...The green light being lit means that the green light works - nothing more

Seriously, depending on the source of the problem it's possible that the only thing getting power is the green light (but not as likely as some other issues).

Most times that I've seen this, it's been a bad power supply. Nearly as often it's been a bad switch on the front of the case. Do you have the skills necessary to test this? If not, I'd suggest that you get a diagnostic from a reputable repair shop.

The only other thing to do is to check the cables and power source. Plug a light into the place that you plug the computer in - to test that. Try another cord from the plug to the computer. Check all the connections inside of the case.

[usasma]

I told my wife this the other day...The green light being lit means that the green light works - nothing more

Seriously, depending on the source of the problem it's possible that the only thing getting power is the green light (but not as likely as some other issues).

Most times that I've seen this, it's been a bad power supply. Nearly as often it's been a bad switch on the front of the case. Do you have the skills necessary to test this? If not, I'd suggest that you get a diagnostic from a reputable repair shop.

The only other thing to do is to check the cables and power source. Plug a light into the place that you plug the computer in - to test that. Try another cord from the plug to the computer. Check all the connections inside of the case.

[electrochimp]

I checked the voltages of the power supply using the jumper from green to black wire connections on the 24 pin connector. The readings were similer to what are listed for each color. I saw later a plug, square with black/yellow wires that I didn't measure the voltage.
The on/off front panel switch feels ok, but maybe I can bypass the switch to test?
Is there a reset?

Thanks

[usasma]

The switch on the front of the case is a momentary contact type. Try shorting the leads briefly to see if that turns it on.

[electrochimp]

I removed the plug from the board and checked continuity through the side slots of the plug with the probes of the multimeter. The panel switch works.

[usasma]

Time to try another power supply. Do you have another computer you can borrow one from? Or, can you purchase one that you can return (in case it's not the power supply)?

Some power supplies have a fuse inside of them - but be careful as the capacitors in there hold a large charge for a long time!

[electrochimp]

i picked up an Antec BP350 Basiq today, should that be ok ? I also picked up a SATA II adapter for the dvd player. Thanks

[usasma]

I'd suspect that the PSU would handle your system, but to be sure check it by using the calculator at this link: http://educations.ne...calc/index.html

[electrochimp]

I installed the the new PSU and no signs of life.

[electrochimp]

I had a network card installed a couple of months ago...two months of good service. I don't know if I should remove this since it did work last time it was on. Can defective devices/drives keep the computer from starting up?

[usasma]

Yes, defective hardware can cause the system to not start. You're at the point where you're going to start swapping parts around - and this is gonna get expensive really fast!

I'd suggest stripping the system of all parts that aren't necessary to start it up (being sure to have the system unplugged from the wall and that you hold onto the metal of the case to prevent static discharge). This is usually the PSU, the mobo, the CPU and it's cooler. It also means to remove the RAM, the CD/DVD drive, the hard drive, and any plug-in cards on the mobo.

If you get signs of life, then add the video card (if so equipped) and try that.
Then try the RAM (1 stick at a time)
Then the hard drive.
After that add the rest of the stuff (one-by-one)

If you don't get signs of life, then it's a problem with what's left - the case, PSU, mobo, or CPU.

Edited by usasma, 30 May 2009 - 06:34 AM.

[electrochimp]

Well, I removed the plugs from the drives and removed network card..didn't work so I just put everything back and it works !!!! Maybe something wasn't making a good connection when I changed the PSU before or can unplugging and plugging back in components do something? I think I'll leave it alone with the new PSU in there.
Thanks for the help.

[usasma]

I'd say you've got it right! Leave it alone since there's nothing wrong with it now.
Backup your stuff in case this happens again and you can't get it started.

Thanks for letting us know!

[Pete1229]

I am having the same problem on the same HP model, I have tried everything stated in this thread plus replacing the motherboard (not the processor). FYI When I plug in the power supply the green indicator light on the PSU illuminates brightly if the ATX cable is NOT connected to the mobo. When the connection is made (ATX to Mobo) and PSU is plugged in, the green indicator light is very dull, barely lit. I have tried all the steps with the new Mobo installed, to no avail. Which is more likely, the PSU or the CPU? I did not replace the original PSU

Edited by Pete1229, 29 June 2009 - 03:45 PM.