Hello people. I have this pc that stopped working about a year ago and i need to repair it for my old lady. This computer one day stopped working (it had shutted off alone a couple times) and wouldnt turn back on. When i plug the power cable it just starts all by itself and reset and power buttons wont do anything. I plugged my POST card and it just wont emmit a code, only clue it gives me is the RST (reset) led is turned on along with the voltajes ones. I checked the manual and it says to check de reset circuit to be connected propperly or otherwise the reset circuit is broken. I interpreted this as to be a problem of the mobo conection with the cabinet's buttons, checked them, unplugged them and this just keeps happening. I have no clue how to get the post card to diagnose if this wont start.
Suggest you pull all external parts (no keyboard, mouse, monitor, etc) and see if it posts. If no then open case and remove all PCI, PCIe card. Does it post? no, leave them out and remove memory. Does it post? (you'll know when it beeps the no memory beep code. Google beep code). No pull hard drive and optical signal and power. Post? No Try breadboarding (see psot above) or swap in a new power supply.
I have tried those things and it isnt posting. I thought it might be the power supply, so i plugged it to the one im using on my PC and exactly the same happens. All voltaje leds (-12 12 +5 +3.3 V) turn on and so does the Reset one, but no code is displayed, even though its breadborded (is that spelled right? )
I have no idea what my next step should be. Should i get a new Mobo? Should i remove the CPU from the mother and see if it posts?
Edit: I am avoiding the removal of the cpu because i have no silicon to replace the old one, but if its necesary i will get some
The symptoms are the same with bad power supply, MB and CPU. Power supply can be bad even if it tests normal with a multi-meter.
The percentage play is bad Power supply. (1) Its more frequent. (2) It's cheaper (3) it's easier to replace.
The next play is bad MB. It's never the CPU.
re the "mobo's south bridge is broken" Excellent. Can your friend point me to how I can diagnose a failed south bridge. The only MB part I know how to diagnose is fails caps. I don't think they fail much anymore, but you diagnosed them this way. http://en.wikipedia.org/wiki/Capacitor_plague
i've only seen exploded capacitors in old mobos. My friend actually proposed the broken south bridge as a theory, he never saw the mobo, he just diagnosed based on the things i told him. His words were, if the mother starts on its own no matter the power supply u use it is probably the south bridge wich handles power management on the mother.