Hi people!
Once again this common and complex problem.
Clues:
~something smells burnt in the tower! But nothing extreme like melt parts etc!
~don't remember what I was doing before on the computer, or if it was working. I woke up and found it like this!
~monitor says no signal, monitor is OK.
~All Fans working.
~on/off button working.
~tried connecting the monitor cable on both the on-board and PCI graphic card, nothing
~tried minimal synthesis, CPU, motherboard, on-board graphic card, still no signal
~no beep, no sound from m-board, even without both RAMs.
~hard-drives seem to work, I hear sound.
~USB ports respond.
~CD/DVD rec neither opens/closes, nor lights on.
~experimented with CPU by taking the fan off and putting it back on quickly. It used to become hot. I suppose this means it is probably working. Intel don't burn easily I heard, and also the CPU is the last one to burn. I don't think it's the CPU.
~north bridge controller, (Intel 865 GV chipset) heatsink becomes hot.
~cleared CMOS 2-pin with jumper, still no monitor signal
~took battery off, put it back on, still no signal.
~Asrock P4i65GV prescott 800, Intel pentium 4 3 GHz.
~unfortunately, no one 's stayed for holidays having a PC to help providing his PC parts.

SO, WHO'S TO BLAME? MOTHERBOARD OR POWER SUPPLY!
MERRY CHRISTMAS TO ALL, APART FROM MY COMPUTER! ANY SUGGESTIONS ALWAYS APPRECIATED!

I would change the p/s first. Chances are the M/B is fried, but the p/s is a cheaper fix, and if the p/s is screwed, it could fry a new M/B (been there, done that, lesson learned)

I agree with Harryleather. Chances are Mobo is dead. If you are not getting posting beeps, that is bad. Power supplies fail much more regularly, they usually just quit altogether though. I have seen a few that will give mixed results just as yours. I would look on the motherboard, around the CPU. You will see capacitors (if you don't know what they are, they are about the size of a regular pencil erasure) The are some of the most common failing devices on a Mobo. If you look closely, you will see they have a "x" grooved into the top of them. As capacitors get old and wear out, they will either leak through those grooves, or they will expand out (posibly just a little) making the top bulged. Again, it is not a definite sign of failure, but if you have caps leaking, they will fail sooner or later.

BTW, I am not sure if you fired up the PC with the heatsink on the CPU, but as durable as Intel are, they can still burn up in about 2 seconds with no heatsink. I would not try that as a test in the future.

What I did with the CPU was that WHILE THE FANS WERE TURNING AND NO MONITOR SIGNAL, I took the heatsink & fans off, touched the CPU(!) and when I felt it just becoming hot, after, say 4-6 seconds, place the fan&heatsink back on. I did this as an awkward idea to see if the CPU becomes hot==working?? I smelled NOTHING burning after this, all evil happened before. I know it is risky/thoughtless, won't do it again(think so!) but I'm sure it didn't burn the CPU. The heatsink is a very good Gigabyte, made of copper, with a fan whose speed is adjustable. It should not be the CPU. At least I don't think I carelessly experimenting, burnt it too! ALL THE CAPACITORS seem fine, nothing bulged, or leaky, just checked them. If I still have time I'll buy a PSU today. Else Monday. Thanks for the advice!

Still no monitor signal with new PSU. Time to check the mobos warranty. I realised that my SVGA monitor cable has 1 pin missing in both ends. I saw others like that one. Anyone knows why?

Still no monitor signal with new PSU. Time to check the mobos warranty. I realised that my SVGA monitor cable has 1 pin missing in both ends. I saw others like that one. Anyone knows why?[/QUOTE]


I don't have a definite answer, But I can give you a little heads up. Standard analog monitors do not need all 15 pins to operate, how many for sure, I do not know. They only use 3 colors, Red, Green and Blue (RGB) each of those colors needs 1 wire, and a ground for a total of six. Then there is a shield and 1 or two others for refresh or latency (been a while since I paid attention) so basically, you could be missing a lot more than just one and you would never miss it.

Bummer about the computer still not working. Also, all I was saying for the CPU is be careful. I do not think I would ever try it as a test if there was any posibility the CPU was still good. You can have the best heat sink in the world, but when its not touching the CPU it does no good.

Hope you get it up in running. If it is an ASUS board, they have up to 3 years warranty.

Ok guys, it was the motherboard! The new motherboard (the same one, Asrock P4i65G) arrived yesterday and now it works fine. Thank you for your interest!