problem with computer starting up

After I shut down my computer, I usually have to wait approx. 8-10 hours before I can turn it back on. I thought maybe there was a problem with overheating, so I've already replaced both fans inside my computer. It didn't help. Any ideas what it might be or how to correct this?

 

This is a new one on me. Try removing the case cover or just one side if the case is built that way and putting a fan blowing right into the side and see if it will boot any faster. This is one way to verify that a chip or something is locking up with the heat. At least you will probably be able to boot it up much faster with the fan..

If that works and it boots faster, I would remove or unplug everything you can before trying it again, even the hard drive. Boot from a floppy and just let it run for awhile to heat up and go at it again. You might be able to track it down this way if it isn't the motherboard, etc., thats essential to turn the computer on. Pull all the memory modules you can if there's more than one, unplug the fans (DON'T uplug the CPU fan), etc. Also, it could be the power supply locking up. If it has relays that might do it. A little detective work over a few hours or days might find the problem. I love a good problem. Have fun.

 

Hi res1966

Heating problems generally don't wait for you to "shut down "... but it could be a heat related problem. My suspicions lie in the on/off switches. With some technical help from more hardware gifted poster, need to bypass the switches immediately after a "hot" shutdown / won't restart to test.

 

Yep, it could be the off/on switch. Actually there isn't an off/on switch on ATX cases. It's just a momentary contact switch that runs to the motherboard/power supply. That's why when you shut down Windows it automatically shuts down the computer. You might open the computer and with a flashlight, locate the two pins that the off/on are connected to. (Your motherboard manual will tell you also. The plugs should also be stamped with what they are.) Note where they are and then locate the two pins for the reset switch. Note where they are. Both the off/on and reset switches are the same, just momentary contact switches. Unplug the off/on and plug in the reset to those two pins. Now the reset swtich is the off/on switch. If you actually have a bad off/on switch this will confirm. If not then you can eliminate that possibility. The voltage there is very low and will not shock you but do all the pins stuff with the power off.

Waiting 8-10 hours for a chip or MOSFET to cool down is a very long time and that doesn't make sense. A chip could get hot and refuse to flip states when the power is again applied but the cases the chips are encased in are designed to dissipate the heat and 8-10 hours is way too long. One of the caps (capicators) could be going bad and shorting to ground but it is unusual for one to start working again.

I would flip the 0/I switch on the back of the power supply off and on a number of times to loosen it up. Then, I would suspect the power supply as being bad.