Delay in startup after pressing power button of desktop computer

Question

It took me a while to find my solution, so I thought I would post my problem and solution here.

The problem: The computer sometimes only turns on after a delay.

After I press the PC's power button three scenarios can happen:

• The system turns on normally and boots up.
• The system turns on after several seconds of delay (3 to 20 seconds) and boots up.
• The system does not turn on.

I have read many messages about BIOS POST etc and power supply issues. But did not match my problem. The word 'boot up' can be ambiguous. So to be very specific, let's differentiate between:

• the system turning on: just after the bower button, you hear the fans start spinning, if you listen closely you can hear the drives start etc.
• the system booting up: this is just after the system turning on, the bios doing its thing (whatever that all is) and finding the boot device.

(If I have diverged from existing terminology, please let me know.)

So the problem seemed to exist in the turning on phase.

It did not happen every time I turned on the pc. If it did not turn on at all, sometimes I switched off the power supply's main switch and waited 20 seconds; then I switched it back and because I have a BIOS setting "turn on after power loss", most of the times the system turned on and booted normally. This hack was starting to get annoying and did not always work.

The question is: why is my system showing this behaviour and how can I fix it? Do I really need to get another power supply?

Answer 1

I had already contacted my vendor for advice, but over the weekend I visited IKEA and I stumbled upon those CR 2032 Lithium round flat batteries which IKEA calls "PLATTBOJ".

Beforehand, while troubleshooting I did find some references to the CMOS battery, but most of the suggestions where leaning towards buying another power supply. Because the batteries at IKEA were very cheap I thought: let's give it a go.

1. Save the current settings of the BIOS.

I entered BIOS first and tried to find some sort of save function (or I would simply have taken pictures if the BIOS did not support this). I found a save and restore function. I could save about 10 different profiles. Jippie! - I saved my config which was custom made by my vendor.

2. Turn off PC, turn off Main Power.
3. Replace the CMOS battery located on the Motherboard.
4. Turn on Main Power, turn on PC, go into BIOS and restore your previous settings.

My motherboard even suggested (via a message on screen) that this was the first time I turned it on. After I restored and saved the settings I turned off the PC.

Then I turned it on again and everything worked fine. The PC turned on immediately after I pressed the power button and I have not experienced any delays after this. (Now about 5 days after.)

Answer 2

For other users that are experiencing this issue, I thought I'd follow up with my own experience. I had the same problem, pushed the power button on the computer and nothing, no beep, no post, etc. After a few minutes the machine would magically turn on. This problem got worse and worse, and the delay before start longer. I replaced the CMOS battery and the problem persisted. I didn't suspect the power supply because the green led on the main board was lit and on. I was wrong. I replaced the power supply, and the machine starts right up again. This is a home build btw, and the power supply that failed was a 4 year old Thermaltake TR-2 600W ATX power supply.