Cold Boot issue
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From: kony on 2 Apr 2008 17:05 On Wed, 02 Apr 2008 11:17:04 +0200, KL <kl(a)tempinbox.com> wrote: >Paul wrote: >> >> The capacitor should be a cylinder with a flat top. There is a seal >> on the bottom of the capacitor, and it can push out if there is >> internal gas pressure inside the cap. If the top bulges, there are >> stress lines in the top of the cap, that are designed to open >> if the pressure inside the capacitor becomes too high. >> >> The electrolyte can leak out the bottom of the capacitor, if the >> seal fails. Sometimes you'll see a brownish deposit under the >> cap when this happens. >> >> If the capacitors were part of the processor power conversion, then >> their failure results in processor instability (crashing just >> as desktop appears etc). They can be replaced, by someone skilled >> with a soldering iron, and solder removal device (solder sucker). >> Motherboards are easy to damage, as the PCB is not of the highest >> quality. The copper foil delaminates pretty easily. >> >> http://www.badcaps.net/images/caps/kt7/image004.png (bulging tops) >> http://www.badcaps.net/images/caps/kt7/image005.png (seal popped on >> the bottom) >> >> Paul > >Thanks Paul. If there is an entire website dedicated to a hardware issue >it seems to be a rather serious one :). > >Some of the capacitors actually seem to be bulged at the top and had the >mentioned mass on them. As I am not really skilled in soldering I guess >it is time for a new mainboard. > >Thanks again Paul, especially for the links. Some would now think it time for a replacement that offers higher performance, but a few just want their existing equipment working again and for that reason badcaps.net does have someone doing board recaps for a fee. http://www.badcaps.net/pages.php?vid=12 I have recapped many a board and do agree it's not the project for someone beginning to learn soldering, but it can be done easily enough given some experience. I don't find the foil delamination problem Paul mentioned to arise very often, but having a high wattage iron with a clean, fairly stout tip is fairly important as many of the caps that fail tend to be across the power and ground planes, both of which 'sink away a lot of the heat needed to melt the solder.
From: Clark on 3 Apr 2008 08:59 KL wrote: > Paul wrote: >> >> The capacitor should be a cylinder with a flat top. There is a seal >> on the bottom of the capacitor, and it can push out if there is >> internal gas pressure inside the cap. If the top bulges, there are >> stress lines in the top of the cap, that are designed to open >> if the pressure inside the capacitor becomes too high. >> >> The electrolyte can leak out the bottom of the capacitor, if the >> seal fails. Sometimes you'll see a brownish deposit under the >> cap when this happens. >> >> If the capacitors were part of the processor power conversion, then >> their failure results in processor instability (crashing just >> as desktop appears etc). They can be replaced, by someone skilled >> with a soldering iron, and solder removal device (solder sucker). >> Motherboards are easy to damage, as the PCB is not of the highest >> quality. The copper foil delaminates pretty easily. >> >> http://www.badcaps.net/images/caps/kt7/image004.png (bulging tops) >> http://www.badcaps.net/images/caps/kt7/image005.png (seal popped on >> the bottom) >> >> Paul > > Thanks Paul. If there is an entire website dedicated to a hardware issue > it seems to be a rather serious one :). > > Some of the capacitors actually seem to be bulged at the top and had the > mentioned mass on them. As I am not really skilled in soldering I guess > it is time for a new mainboard. > > Thanks again Paul, especially for the links. If you have decided to get a new motherboard anyway, then do some checks first. Try booting to a boot CD,since there may be a problem with your hard drive. You could open the system up and take out everything you don't need to boot and check and reseat your other cards, cables, and memory. Clean it out while you are in there. Because you think you changed the memory, don't just assume it can't be that. If you can remove part of it or change it around, you should try that also. But memory problems should give you a beep code, or motherboard lights or something. I am still leaning toward some bad device driver, or maybe a virus, or even a loose cable. Since a warm boot works, the loose cable probably isn't the cause, but you might check it anyway. I can't remember right now what the difference as far as what is not loaded during a warm boot as opposed to a cold boot. I am assuming also that when you say cold boot, you just mean after a complete shutdown, and immediate restart (at least 10 seconds, of course). If you do have to leave it overnight before the problem arises, the fact the hard drive also cools down might be a factor. Clark
From: KL on 3 Apr 2008 11:27 Clark wrote: > > If you have decided to get a new motherboard anyway, then do some checks > first. Thanks again for your helpful reply Clark, actually I already did most of the checks you mentioned. Meanwhile I purchased a new mainboard and am in the process of installing it. I hope this will finally resolve this issue. My only concern now is that capacitors of the power supply could also be involved, hence I'd like to take a look at it too, but am a bit worried about the remaining voltages and so maybe someone could state after which time of being fully disconnected it should be safe to open it. > Try booting to a boot CD,since there may be a problem with your > hard drive. The was one of my initial assumptions, but none of the checks I ran pointed to a faulty hard drive. > > Because you think you changed the memory, don't just assume it can't be > that. If you can remove part of it or change it around, you should try > that also. But memory problems should give you a beep code, or > motherboard lights or something. Yes, I already checked for this too. I ran Memtest86+ (please dont remind me how tedious it was to get a USB stick bootable on XP ;) ) several times individually over the memory chips. > > I am still leaning toward some bad device driver, or maybe a virus, or > even a loose cable. Since a warm boot works, the loose cable probably > isn't the cause, but you might check it anyway. The reason why I almost ruled out the software possibility was not only because it happened immediately after the XP booting (drivers and especially viruses usually take place a bit later) but also because the error remained even after several reinstalls. > I can't remember right > now what the difference as far as what is not loaded during a warm boot > as opposed to a cold boot. From the operating system point of view there shouldnt be any difference. > > I am assuming also that when you say cold boot, you just mean after a > complete shutdown, and immediate restart (at least 10 seconds, of > course). If you do have to leave it overnight before the problem > arises, the fact the hard drive also cools down might be a factor. I actually tried both scenarios. Thanks again Clark.
From: kony on 3 Apr 2008 15:05 On Thu, 03 Apr 2008 17:27:41 +0200, KL <kl(a)tempinbox.com> wrote: >Clark wrote: >> >> If you have decided to get a new motherboard anyway, then do some checks >> first. > >Thanks again for your helpful reply Clark, actually I already did most >of the checks you mentioned. > >Meanwhile I purchased a new mainboard and am in the process of >installing it. I hope this will finally resolve this issue. > >My only concern now is that capacitors of the power supply could also be >involved, hence I'd like to take a look at it too, but am a bit worried >about the remaining voltages and so maybe someone could state after >which time of being fully disconnected it should be safe to open it. Usually it's safe to open roughly 20-30 seconds later. Give it a few minutes instead or to be extra cautious you could wait a few hours but I have never found that necessary, out of curiosity I check voltage on any I haven't waited long on and never found dangerous voltage remaining. However, technically speaking if you were to only take off the screws and handle the outside of the casing, even with it live (which I don't suggest doing, I'm just posing the scenario for example) on a non-conductive surface you would merely need to refrain from touching anything metal inside. > >> Try booting to a boot CD,since there may be a problem with your >> hard drive. > >The was one of my initial assumptions, but none of the checks I ran >pointed to a faulty hard drive. Now that you've found the bad caps, there's not much point in testing anything else until you have a known good motherboard in for the testing. Instable motherboard can lead one in all kinds of wrong directions. >The reason why I almost ruled out the software possibility was not only >because it happened immediately after the XP booting (drivers and >especially viruses usually take place a bit later) but also because the >error remained even after several reinstalls. One thing to keep in mind is that if the system were instable but not so much to crash, there is the potential for data generated or transferred to have become corrupt. I mean files written on the hard drive since the instability began should be checked, and if the OS still isn't stable (if reusing existing OS install instead of a clean reinstall) then it should be installed again once the system proves stable.
From: KL on 3 Apr 2008 15:24
kony wrote: > > Usually it's safe to open roughly 20-30 seconds later. Give > it a few minutes instead or to be extra cautious you could > wait a few hours but I have never found that necessary, out > of curiosity I check voltage on any I haven't waited long on > and never found dangerous voltage remaining. Well, I waited for almost 20 hours :). I opened it meanwhile and tried to take as much care as possible. The power supply itself looked fine, at least from looking at it. > > However, technically speaking if you were to only take off > the screws and handle the outside of the casing, even with > it live (which I don't suggest doing, I'm just posing the > scenario for example) on a non-conductive surface you would > merely need to refrain from touching anything metal inside. I was cautious because I am not really a hardware guy and missing skills/knowledge/experience often scare people off ;). > > Now that you've found the bad caps, there's not much point > in testing anything else until you have a known good > motherboard in for the testing. Instable motherboard can > lead one in all kinds of wrong directions. Great News! New motherboard and the problem still appears ;). Well, I am slowly starting to get out of ideas as well as to suspect either the power supply (even if it seems to look fine) or the video card to cause it. > > One thing to keep in mind is that if the system were > instable but not so much to crash, there is the potential > for data generated or transferred to have become corrupt. I > mean files written on the hard drive since the instability > began should be checked, and if the OS still isn't stable > (if reusing existing OS install instead of a clean > reinstall) then it should be installed again once the system > proves stable. Yes, thats what I planned. Thanks kony. |