Page 1 of 2 12 LastLast
Results 1 to 15 of 18
  1. #1
    Super Moderator BATcher's Avatar
    Join Date
    Feb 2008
    Location
    A cultural area in SW England
    Posts
    3,421
    Thanks
    33
    Thanked 195 Times in 175 Posts
    A local charity has a Dell Dimension 5150, whose system unit occasionally (say every few weeks) will not power on. The internals are quite clean and gunge-free. The BIOS is at the latest level. Yes, of course it is out of warranty! I have already reseated the memory and checked all the internal connectors on a previous visit, and after doing this it did power on! So I thought that was the problem fixed.

    Has anyone any theories why this inability to power on might happen? My only one at the moment is that the front power-on button might intermittently fail to work, so I'm going to suggest that they leave this button alone and in the 'on' position, and power it off at the mains socket at night... Any other Bright Ideas welcomed!
    BATcher

    Time prevents everything happening all at once...

  2. #2
    Plutonium Lounger
    Join Date
    Oct 2001
    Location
    Lexington, Kentucky, USA
    Posts
    12,107
    Thanks
    0
    Thanked 1 Time in 1 Post
    Quote Originally Posted by BATcher View Post
    ... system unit occasionally (say every few weeks) will not power on ...
    Interesting, possibly funny coincidence! I have TWO sitting here with the same symptoms except these will not power on at all. One belongs to me and the other to a staffer at the nursing home - an HP.

    I too have done the things you have and can't get hers to turn on so I was debating a possibly dead power supply. But, when I told her that it could also be the motherboard, she didn't want to invest in a new power supply. So, guess what happened! Her HUSBAND went out and bought a new computer asking me to slave this old drive to it so they can capture their stuff.

    Good luck, sir, and I'll be keeping an eye here to see what you learn.

  3. #3
    Plutonium Lounger Leif's Avatar
    Join Date
    Dec 2000
    Location
    U.K.
    Posts
    14,010
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Quote Originally Posted by BATcher View Post
    My only one at the moment is that the front power-on button might intermittently fail to work, so I'm going to suggest that they leave this button alone and in the 'on' position, and power it off at the mains socket at night... Any other Bright Ideas welcomed!
    Is this 'front power-on button' a mechanical/electrical switch, in that it physically switches the mains power? It's a few years since I've seen one of those on a Dell!

    If it is, presumably you can tell if it has worked or not by there being some kind of power-on indication LED somewhere, even if it is on the motherboard. Yes/No?

    Most modern power switches are actually low-voltage (~5VDC) signal switches. Mains power is applied all the time and a small secondary power supply provides enough power to enable this on/off switch, plus wake-on-lan requirements, etc. When the PC is turned 'ON', the primary power supply is enabled to provide enough energy for the HDs etc.
    Because the on/off switch is not itself turning the mains on, it can have multiple functions, e.g. press-and-hold to power down, short-press for reboot, etc.
    If this type of switch is in use in your case, there could be a variety of reasons for failure. The switch itself could have failed, or have dirty contacts. A signal de-bounce capacitor could have failed, or a dry joint or failed logic circuit having an affect. Because the switched signal is low voltage and low current, it doesn't take much to stop it from working.

    (I did have a similar problem with an old Dell a couple of years back, but in my case, it would only switch on 1 in 20 times. I traced the signal back as far as I could but eventually gave up, assuming a failed IC.)

  4. #4
    Super Moderator BATcher's Avatar
    Join Date
    Feb 2008
    Location
    A cultural area in SW England
    Posts
    3,421
    Thanks
    33
    Thanked 195 Times in 175 Posts
    Quote Originally Posted by Leif View Post
    Is this 'front power-on button' a mechanical/electrical switch, in that it physically switches the mains power? It's a few years since I've seen one of those on a Dell!

    If it is, presumably you can tell if it has worked or not by there being some kind of power-on indication LED somewhere, even if it is on the motherboard. Yes/No?
    Well, that's a good question - I just call it the Power-On Button, and I press it, and when it works fans burst into life and the PC boots!
    I'm assuming the usual green motherboard light comes on at the same time, not to be confused with the green light on the NIC.

    I'll take the cover off tomorrow and have a look before powering up. But from what you're saying, I'm not going to get anywhere with my theory about leaving the front button switched on (because it doesn't work that way), and then controlling the power via the 13A socket...

    The main problem is, of course, the very occasional nature of the failure - about 1 time in 50 or so.
    BATcher

    Time prevents everything happening all at once...

  5. #5
    Plutonium Lounger Leif's Avatar
    Join Date
    Dec 2000
    Location
    U.K.
    Posts
    14,010
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Quote Originally Posted by BATcher View Post
    I'm assuming the usual green motherboard light comes on at the same time, not to be confused with the green light on the NIC.
    I think it is quite normal for there to be another small LED (yellow/orange?) somewhere on the motherboard to indicate mains power is available - regardless of whether or not the PC is 'ON'.
    I've certainly noticed this on our Dells here when you take the cover off and the mains is still connected.

  6. #6
    Plutonium Lounger Leif's Avatar
    Join Date
    Dec 2000
    Location
    U.K.
    Posts
    14,010
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Quote Originally Posted by BATcher View Post
    Well, that's a good question - I just call it the Power-On Button, and I press it, and when it works fans burst into life and the PC boots!
    I did mean to add - does the switch appear to mechanically latch, in that you can see it is in physically different positions when 'on' and 'off'?

    It could still be a low voltage logic-type switch, just latching as opposed to momentary.

    (In my view, there is a good reason for the low-voltage switching, albeit that there can be unnecessary quiescent power wasted. Apart from enabling 'background power' to always be available for network cards, modems, etc., the pc is intrinsically safer, with all mains voltages contained within the 'PSU cage'. If there is a mains on/off switch, it is most likely to be by the IEC mains inlet on the PSU itself.)

  7. #7
    Super Moderator BATcher's Avatar
    Join Date
    Feb 2008
    Location
    A cultural area in SW England
    Posts
    3,421
    Thanks
    33
    Thanked 195 Times in 175 Posts
    Quote Originally Posted by Leif View Post
    I did mean to add - does the switch appear to mechanically latch, in that you can see it is in physically different positions when 'on' and 'off'?
    I think it's just a "press to change state" switch, but I will check this tomorrow. Thanks!
    BATcher

    Time prevents everything happening all at once...

  8. #8
    Super Moderator BATcher's Avatar
    Join Date
    Feb 2008
    Location
    A cultural area in SW England
    Posts
    3,421
    Thanks
    33
    Thanked 195 Times in 175 Posts
    Quote Originally Posted by BATcher View Post
    I think it's just a "press to change state" switch, but I will check this tomorrow. Thanks!
    And so it is (and the machine is actually a Dell Inspiron 530). There's a blue central light on the power button, and at the back a green light next to the PSU but no On-Off rocker switch. The motherboard has an orange light when power is applied to the PSU. I've checked every internal plug and socket, and all are solid. So I'm fairly baffled. The user is going to keep a note of any occasion when it won't power up. Maybe it should be left on 'permanently'?
    BATcher

    Time prevents everything happening all at once...

  9. #9
    Super Moderator
    Join Date
    Dec 2000
    Location
    Renton, Washington, USA
    Posts
    12,560
    Thanks
    0
    Thanked 4 Times in 4 Posts
    I had issues with one tower, where the switch housing cracked away from the front of the case. As one pressed the switch, the crack separated a bit more and sometimes far enough that the switch would not toggle between positions.

    Now running HP Pavilion a6528p, with Win7 64 Bit OS.

  10. #10
    Silver Lounger
    Join Date
    Jan 2001
    Location
    Swanzey, New Hampshire, USA
    Posts
    1,707
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Quote Originally Posted by BATcher View Post
    Maybe it should be left on 'permanently'?
    Only in the case of severe weather when there is the possibility of losing electric power do I shut down my machines. They run 24/7. I've chosen to do this since I first owned a PC, yes, even after reading what all the [s]environmental wackos[/s], er ummm planet conscientious, Nobel prize contenders/hopefuls have written to warn how dangerous and wasteful this is.

    Actually, I do have my monitor set to turn off after 1 hour of non-use.
    Jeff
    simul iustus et peccator

  11. #11
    Super Moderator
    Join Date
    Dec 2000
    Location
    Renton, Washington, USA
    Posts
    12,560
    Thanks
    0
    Thanked 4 Times in 4 Posts
    I do the same on 7/24 except when weather or being away for a extended time.

    Some of these same "[s]environmental wackos[/s]" have a 1,000 or so red and green lights showing when the house is dark. They forget about all of those other toys that must have "Instant on" feature

    Now running HP Pavilion a6528p, with Win7 64 Bit OS.

  12. #12
    Uranium Lounger viking33's Avatar
    Join Date
    Jun 2002
    Location
    Cape Cod, Massachusetts, USA
    Posts
    6,308
    Thanks
    0
    Thanked 1 Time in 1 Post
    Quote Originally Posted by Pilgrim View Post
    Only in the case of severe weather when there is the possibility of losing electric power do I shut down my machines. They run 24/7. I've chosen to do this since I first owned a PC, yes, even after reading what all the [s]environmental wackos[/s], er ummm planet conscientious, Nobel prize contenders/hopefuls have written to warn how dangerous and wasteful this is.

    Actually, I do have my monitor set to turn off after 1 hour of non-use.
    We aren't going to get into the "leave it on, turn it off" debate AGAIN are we?
    BOB
    http://lounge.windowssecrets.com/S/flags/USA.gif http://lounge.windowssecrets.com/S/f...sachusetts.gif


    Long ago, there was a time when men cursed and beat on the ground with sticks. It was called witchcraft.
    Today it is called golf!

  13. #13
    Silver Lounger
    Join Date
    Jan 2001
    Location
    Swanzey, New Hampshire, USA
    Posts
    1,707
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Quote Originally Posted by viking33 View Post
    We aren't going to get into the "leave it on, turn it off" debate AGAIN are we?
    Evidently not! The OP asked the question (perhaps rhetorically?) that perhaps he should leave his system on. Dave and I simply answered that to do so wouldn't be a bad choice, at least that is our personal practice. If someone chooses to not leave their PC on, then what's wrong with that?
    Jeff
    simul iustus et peccator

  14. #14
    2 Star Lounger
    Join Date
    Jan 2001
    Location
    Rothesay, New Brunswick, Canada
    Posts
    135
    Thanks
    0
    Thanked 0 Times in 0 Posts
    I have had the same problem with my PC. However, it only happened when I removed the fuse for the wall plug to which it is attached. I forgot both times to shut down the computer before removing the fuse to do some electrical work in my house. Both times it eventually powered up again after playing with the wires on the computer.
    Even when the computer didn't power on the keyboard number lock light was on and the sound card was working. No fan or other perypheral came on.
    Once poweredup I could shut down and it would restart with no problem.
    My solution has been not to forget to shut down before cutting power to the electrical circuit.
    I realize this doesn't explain why it happens but perhaps some of the gurus can come up with some explanation.
    BTW I'm using XP Home edition SP3 on AMD Athlon 64 X2 Dual 2.83 GHz
    Cheers,
    Jack
    Jack

  15. #15
    New Lounger
    Join Date
    Dec 2009
    Location
    North of Dallas, Texas
    Posts
    1
    Thanks
    0
    Thanked 0 Times in 0 Posts
    I recently had a problem similar to what has been described in this thread. After talking to a few different Dell technicians, I was given a solution that has worked a few times now. It seems that some Dell systems can store up static electricity and cause power up problems. The process of dissipating this static electricity is quite simple and easy. All you have to do is unplug the power cord from the system and then press & hold the power button for at least 20 seconds. After that, plug the power cord back in and power up the system. The system should start up normally. I have had to perform this little trick two or three times across different Dimension and XPS type systems. Hope that helps.

    Regards,
    Jeff W.

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •