Computer only switches on after (un)plugging in. Why?

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DavidT
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Computer only switches on after (un)plugging in. Why?

Postby DavidT » 5 Dec 2017, 10:43am

I have an aging computer, but (touch wood) it does work. However in the last month or so it will not switch on....until that is I unplug the stack, wait 30secs or so then plug it back in again. It then starts and runs with no problems, and allows normal shut down. Then it won't start again until I repeat - as above. I have very poor computer knowledge, but am intrigued as to what is going on here. I wonder if anyone can enlighten me in simple terms?

Meanwhile I am bracing for an investment in a new computer, which is presumably on the cards?

Best Regards
David

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[XAP]Bob
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Re: Computer only switches on after (un)plugging in. Why?

Postby [XAP]Bob » 5 Dec 2017, 10:46am

What type of computer.

Sounds like a PSU failure (or imminent failure) which might be only a few quid to replace.
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.

kwackers
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Re: Computer only switches on after (un)plugging in. Why?

Postby kwackers » 5 Dec 2017, 10:51am

PC's are already 'on' and are just waiting for you to press the power button which is just a 'soft' power, i.e. it doesn't physically disconnect.
What's probably happened is a fault on the power supply means the soft on no longer works unless it's reset, which is what happens when you unplug it.

There's a decent chance that if you can be bothered using it as is it'll carry on working.
My recommendation. Soft power it off like usual, then when it goes to sleep, turn it off at the wall. Next day turn it on and power it back up.

Alternatively, assuming it's a standard PC then the power supply is just a module which isn't expensive. You could just swap it for a new one.

pete75
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Re: Computer only switches on after (un)plugging in. Why?

Postby pete75 » 5 Dec 2017, 10:54am

Most likely a problem caused by an ageing power supply. They're not expensive from somewhere like ebuyer http://www.ebuyer.co.uk so it's worth changing it before you spend any money on a new computer or paying someone to diagnose and fix the problem. It takes under 10 minutes to swap a power supply. There will be spec details on the power supply. Get one of similar or higher power output. Unless your computer is extremely old it will use an ATX power supply which has been the norm for most of this century.

DavidT
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Re: Computer only switches on after (un)plugging in. Why?

Postby DavidT » 5 Dec 2017, 10:59am

HP Compaq. Is that enough info? Sorry to be a dunce...

DavidT
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Re: Computer only switches on after (un)plugging in. Why?

Postby DavidT » 5 Dec 2017, 11:01am

Thanks for the feedback. I'll try not to panic just yet then, and the explanation of the "soft" power is interesting.

mercalia
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Re: Computer only switches on after (un)plugging in. Why?

Postby mercalia » 5 Dec 2017, 11:19am

if the 'puter is important get a new power supply, other wise it may fail and "electrocute" your pc

Any pc from the dual/quad era ( 2006ish ) is stil viable even for some intensive tasks eg I ripped a bluray to put on my media center last night and it took just 23 minutes using the video card as a support processor, it did all the heavy lifting

pete75
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Re: Computer only switches on after (un)plugging in. Why?

Postby pete75 » 5 Dec 2017, 12:48pm

DavidT wrote:HP Compaq. Is that enough info? Sorry to be a dunce...


No HP Compaq made many different models. Should be a type no on a sticker on back or side.

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Tigerbiten
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Re: Computer only switches on after (un)plugging in. Why?

Postby Tigerbiten » 5 Dec 2017, 1:25pm

When you say "fail to start" .....
Does nothing at all happen when you go to start it or do you get a very brief surge of activity before everything goes dead until you unplug it ??

If you get a very brief surge of activity, the fans start then stop, then it could be something a silly as the MoBo detecting the CPU fan is a bit sticky and is starting to spin up to slow, so the MoBo shuts everything down. Once the MoBo detects a fail, it keeps everything shut down until a complete power off.
Or it could just be a failing PSU ...... :D

mercalia
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Re: Computer only switches on after (un)plugging in. Why?

Postby mercalia » 5 Dec 2017, 2:13pm

of course could simply be a faulty switch - I have had to replace broken ones very occasionally

hamster
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Re: Computer only switches on after (un)plugging in. Why?

Postby hamster » 7 Dec 2017, 9:34am

I had an identical problem on my HP. It's usually the power supply.
To cut a long and tedious story short, there is was a problem specifically with premature component ageing. A new power supply brick should sort it.