puzzled with system start up

[kolos]

Hi All,

I hope you will able to help me, thanks in advance!

For the last 2-3 months, my PC was behaving very strange. Every 2-3 days it did not boot up. I had to turn the Midi tower to the side, sometime even shake it, and then it booted up. (the shaking was come only after I took it apart 3 times put it back, and still could only fix it with shaking ... but sometimes I had to wait 2-3 hours, and than it booted up normally. When it started it was running for days without a freeze.

I was quite puzzled, what the hell could be wrong.

What does not boot up means? All fans, hdd, etc starts up, green light flashing, flat screen on stand-by, mouse, keyboard are dead (without any light).
(I also tried assemble the motherboard (Asus A7S8X + 512mb Samsung DDR 400 ram, AMD 2400+, on board VGA / ATI Radeon 9600?) - still monitor does not exit standby mode.)

About 1 week ago, shaking stopped working. Whatever I did, it just did not left stand-by mode (the monitor, LG M1917TM).

I thought motherboard must have been died, as I though the boot-up procedure stops). At X-mas I wanted to by a new PC, so I bought it ahead with a month.

Tonight I assembled a Asus P5B with 2x 1Mb DDR II RAM Samsung, E6300 Core Duo, Asus GF 7600 GS Silent 256 Mb.
After 5 min searching I realised that I forget the 4-pin power supply and the motherboard sarted up outside of the box - I though I made my new system.

I plugged keyboard, monitor on the system and was ready to look around in my new BIOS. BUT the monitor stayed in stand-by.
The sequence:
- Power on button switched on
- Fans are running
- PS/2 Keyboard flash once (USB optical mouse remain offline)
- and here is the end ... monitor stays on stand-by, keyboard does not even react on numlock, fans are happily running
(no beeps, though I am not sure my speaker is working, as I never heard it working (how to test?))

At this point I become really really puzzled.

I have changed all components except power supply and monitor.

My question: which one is the faulty one?

I could not imagine that the power supply is wrong, as the error in the beginning was coming and going (so far for me a power supply was fried, or working). It is a 300 W DTK supply, nothing on it except the motherboard, lack of power is unlikely.

So can it be the monitor? LG M1917TM, should I take it back to the shop? Anybody seen a monitor does that? (Before you suggest, I tried 1 analogue cable and 1 digital cable as well, with 2 motherboards and 3 video cards – assembly is fine as well, though I do not have another monitor for testing

I was started to test the screen. It reacts perfectly: after plug-in it is looking for a source, I connect either analogue, or digital cable to a motherboard/video card, it immediately recognise the source and display a message (input found, prepare for stand-by) and goes to stand-by, but never comes back

Any idea?

Thanks for reading, and for the help as well.

Kolos

[Cricket]

Get another power supply.

I've never heard of DTK power supplies before so I don't know what kind of quality it has but 300 watts isn't enough to power a C2D based computer reliably.

Cricket

[moodyblues100]

Power Supplies that are underpowered or starting to fail, may act a little flakey rather than failing completely.

[kolos]

Today I got a JEANTECH, ATX 500W from PC World - I read it on a forum that is ok quality and was available localy.

I also checked that 400W should be sufficient (based on Asus info), so I took 25% higher. (specially only for the motherboard, without drives)

Still nothing

Tomorrow I will test it with other monitor, after that I guess I will have to take it back
(Could the old power supply kill the MB? - I guess everything possible, but does not seem likely)

[Planefreak]

Never heard of a problem to your caliber. You mentioned that you were using an Asus board. I don't know if that one support Instant Music or Keyboard/mouse auto on. Mine does. Although my keyboard lights are on all of the time. I have a laser mouse so I am not sure when it actually comes online. First, make sure you have the white cpu power plug in the middle of the board plugged in. I don't think you can get to bios with out a cpu. Second check that you are using a 24 pin atx power supply. If you don't hear the "POST" (power on self test) you will not see the bios start up screen. Peripherals can also stop a booting PC. If I have my flash drive piugged in my PC will not get passed the bios screen. Also, if your speakers are working properly and there is a failure in bios it should alert you.

[ktkendall]

Time to start with the basics:

http://forum.pcmech.com/showthread.php?t=132409

Out of the case new build troubleshooting steps..