PC will only switch on after PSU is 'discharged'

  Newuser38 18:44 01 Apr 03

HP Pavilion 600 Athlon, 256sdram 2xhdd running 98se and Xp home dual boot. PSU special HP 185

All of a sudden slowed down and powered off. Could not switch it on. Checked all the Dead PC etc threads. Then went to HP who on web helpsite suggested holding power switch (button) in for 60 secs to discharge PSU. Did that and then PC could be switched on. After a time it powered down again. Cleaned out much old dust and fluff blew out same from what is labelled as processer a largish black structure with fins sitting under a case fan. Still would not start in the normal way but does after holding in switch button.

Checked all contacts etc and seem no problems. Machine is now running as normal after starting it as above. As I dont want to have to press the button for 2mins every time I want to turn it on would appreciate help please.
PSU is a special HP one 20 months old after I blew the previous one by moving voltage switch. Machine has now run for 2hrs 15 mins w/o power down??

  Newuser38 19:38 01 Apr 03


  flecc 20:33 01 Apr 03

Have you tried switching off at the mains switch after shutting down?

Try that and then see if it boots from a single press of the switch. If it does, it's likely to be a power supply fault again.

  Newuser38 21:21 01 Apr 03

Thanks I will try that when I shut down. Just back from evening meal and 1 glass of red. I am making sure I really have everything backed up in case it finally gives up. Will it make any difference that it and machine 2 go via surge protection to main switch?

  Newuser38 21:19 05 Apr 03


Yes it does restart if I do as you suggested and restart immediately. Once it has been running for a time, and it has now gone all day w/o powering down, it will restart at once after shutdown. If I leave it overnight it will only start after I use the HP discharge system.

Does this still look like PS or could it be a switch ?

  flecc 00:35 06 Apr 03

It's unlikely to be the switch since that has no element which could be time dependent. The power supply has capacitors which leak to zero charge with time, so the power supply has to be the chief suspect although I've never heard of this before.

The fact that this has gone before could be an indicator of course, it could be a weakness in the design of that special item. It certainly sounds as though HP are well aware of this fault.

  Newuser38 10:20 06 Apr 03


Thanks, I note that HP no longer supply the model which I have had twice, so ?. The new one, replacement, is 200 watt instead of 185 and £10 more expensive £84 + delivery. The problem is the PC case is not standard so I cannot just go out and pick up one from any where.Will try our mutual friends Maplin on the offchance. Thanks as always for the help, all the normal PSU commentators seem to have gone very quiet on this.

  flecc 13:51 06 Apr 03

That's another clue I think, the slightly higher rating which could improve matters. 200 watt these days is a very low output and the £84 is a terribly high price, but as you say, there's no option with these machines.

I think it best to avoid some of these major suppliers, HP, Packard-Bell, Time/Tiny, and even some of PC World's offerings, since they often use these non-standard components, leading to later expense.

  Newuser38 17:30 13 Apr 03

It was suggested by a non-HP person that I might consider re-casing if I could not get power unit to fit.
Bought a new case incl 300PSU and case fan etc. Before doing the big job I decided to try the PSU from the new case in The HP. It fitted, just, so I took out the HP one and put the new one in. It works, no more hang up. Hope the rest keeps going. Case now put by for future possible use.

  Newuser38 17:31 13 Apr 03

Should have said with a slight physical modification to HP case to accomodate power switch on the new PSU.

  justme 18:31 13 Apr 03

Well done Newuser38 on modifying your HP computer case. That's what angle grinders were made for 8-)

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