Computer will only start sometimes
 

Switch on the power and nothing happens. But sometimes the computer does come on. It would be easy to get the idea that it will come on if there has been quite a time before it was last on; but am not at all sure of this. Is this something to worry about?

(Incidentally, thought it was the on/off switch, so cut it off and twisted the wires together. So now the switch on the wall plug has become its on-off switch. Is this liable to damage it?)

Thanks any help.

:)

Sounds like you are pretty happy poking around inside the case. Not sure about that business with the power switch, so I'll pass on that.

One thing to try is to disconnect all the power connectors to the m/board and drives and see if the power supply on its own still shows the same problem. If it does it is not too expensive to replace it.

If power supply is OK, start reconnecting stuff one at a time, starting with the m/board, and see at what point the problem recurs. In my experience a faulty m/board can stop the power supply starting up.

Thanks for reply! Will do that.

Take it the fan on the power supply will start when it's disconnected - so I'll know its working.:)

The computer I use at my school has the same problem sometimes and it's caused by the power supply because after I turn it off and back on via the rear switch, the computer fires up just fine. So it's probably the power supply which aren't too expensive if you buy them at the right place such as Multiwave or find one on Ebay. In fact, my friend got a 500 watt power supply on Ebay for around $30 and it works great.

You can damage the motherboard if you have the power switch cable twisted together all the time. You just need to lightly make a contact for a few seconds. You can buy a SPST (single-pole, single-throw) switch from any electronic store. Make sure its the model that is always open.

The capacitors on the motherboard could be going or the MOSFETs are not switching right. Usually the capacitors go first because the high frequency of the switching power supply kills them. You can replace them if you a the right equipment.

For power supplies I would suggest buying either Enermax, PC Power & Cooling, or Zalman. You should look for atleast 400 watts if you have a few hard drives, cd-roms, powerful graphics card, and a very fast processor near 3 gigahertz or faster. Many power supplies state they can handle their maximum wattage but this is not true. More expensive power supplies and sometimes heavier ones can handle their maximum wattage ratings.

Thanks for help.:)

Electro - can I use the origional switch? Save me buying a new one.

Is that the most intelligent question ever asked?

:)

You are too cheap to buy a switch that costs a few US cents...sheesh!

If you are really that cheap, find some electronic devices that don't work anymore and desolder the switches.

Thanks.

But have a theory about this:

A few posts further up, yesterday, someone was asking the same question - seemed like: bit ambiguouse. They made the point I should have made: that had kept swithching computer on and off a lot before problem developed (trying to get a network up with only one keyboard.)

How about: BIOS is *designed* to stop the ignorant from buggering the computer; if user keeps switching on and off with low time, measure by clock, between it does what has happened to me, it refuses to switch on untill some time has elapsed. The appauled punter rings the shop; the shop says 'calm yourself my dear' or 'That'll be a few US cents' if there's no warranty. Think this entirely possible.

(Possible the people on here might not know this as common knowledge for they do not ABUSE the on/off button and they have a shed load of keyboards and everything else you can think of.)

Anybody know??

:scratch: