• Diagnosing between processor and motherboard failure on a laptop
    9 replies, posted
I've been trying to help my friend sort out what's wrong with his laptop, and we've narrowed the problem down to either the processor or the motherboard, but are having trouble diagnosing which one is responsible! All the other relevant hardware has already been tested, and so we can say that it's one or the other with a fair amount of certainty, but that's as close as we can come. Here is the issue: The machine fails to boot. It doesn't even get to a BIOS screen. When the power is turned on, the lights on the laptop turn on and the fans all begin to spin, but then it simply poops out. The lights remain on, but the fans all stop spinning, and there is no more activity. This happens after just a second or two of the machine attempting to boot. This is occurring on every attempt to boot. Prior to the full collapse, my friend says he was experiencing frequent crashes and blue screens, and several of the buttons on his laptop would intermittently cease to work (power button, keyboard keys, etc). This is a relatively new and powerful laptop, so we're hoping to have to avoid scrapping the machine. My friend's hope is that we can either determine what is the problem reliably enough to either sell it as is, with it clearly stated as being nonworking, and links to the parts needed to repair it, or to do the dirty work ourselves and try to resell it afterwards. Time is pretty sensitive here, as the laptop is his only computer, and he'll need something worked out before his next school semester starts. My money is on the motherboard being the problem, but I'm not terribly experienced in this, and would really appreciate a few other opinions! If it were a desktop, I'd just start switching in my spare parts until something worked, but I don't have any spare laptop bits laying around! We can't afford to gamble on which module we purchase, so before we go any further we need some amount of certainty as to what the problem is. For clarification: this is an Asus N73J series laptop.
My guess is the motherboard, but it's hard to say. Did it have a history of overheating before it died?
Not that I can say with any certainty. He was usually pretty good about that stuff. Any time the machine was in use, he had it on a cooling pad, and he didn't marathon on it all that often! If the laptop overheated any, it would have had to have been a problem with the machine, not the handler. From he was telling me about the issues he was having, it didn't sound like a heating problem. The machine was doing all sorts of weird stuff, but after a reboot it would always behave normally again for a while. At least until it didn't.
If the laptop was BSODing, that's usually a sign of bad memory. You said you tested everything, but did you run memtest? (not windows memory diagnostic.) Really bad memory can cause a machine to fail to even start. Another thing, did you test the voltage on the CMOS battery? (not the laptop battery) Some laptops have a "suicide battery" feature where the laptop ceases to work if the CMOS battery is either dead or has too low of a voltage (usually between 2.0-2.4v.) The CPU being bad is very unlikely, unless the cooling system wasn't installed correctly and allowed the CPU to persistently overheat.
If you haven't gone poking around where you shouldn't of on it and if the laptop is fairly new then don't you still have the warranty?
I'd definitely say motherboard. The odds of a CPU being bad are about 1 in every million chips produced.
[QUOTE=GiGaBiTe;41683277]If the laptop was BSODing, that's usually a sign of bad memory. You said you tested everything, but did you run memtest? (not windows memory diagnostic.) Really bad memory can cause a machine to fail to even start. Another thing, did you test the voltage on the CMOS battery? (not the laptop battery) Some laptops have a "suicide battery" feature where the laptop ceases to work if the CMOS battery is either dead or has too low of a voltage (usually between 2.0-2.4v.) The CPU being bad is very unlikely, unless the cooling system wasn't installed correctly and allowed the CPU to persistently overheat.[/QUOTE] Hi, Bohb. OT: Isn't that CPU embedded on the mobo?
[QUOTE=voltlight;41683383]I'd definitely say motherboard. The odds of a CPU being bad are about 1 in every million chips produced.[/QUOTE] Yeah, we're likely just gonna take the gamble and order a replacement board. The simplest answer is usually the correct one, and all that. [QUOTE=Michael haxz;41683351]If you haven't gone poking around where you shouldn't of on it and if the laptop is fairly new then don't you still have the warranty?[/QUOTE] Unfortunately, it was only under a one year warranty. [QUOTE=GiGaBiTe;41683277]If the laptop was BSODing, that's usually a sign of bad memory. You said you tested everything, but did you run memtest? (not windows memory diagnostic.) Really bad memory can cause a machine to fail to even start. Another thing, did you test the voltage on the CMOS battery? (not the laptop battery) Some laptops have a "suicide battery" feature where the laptop ceases to work if the CMOS battery is either dead or has too low of a voltage (usually between 2.0-2.4v.) The CPU being bad is very unlikely, unless the cooling system wasn't installed correctly and allowed the CPU to persistently overheat.[/QUOTE] It's not the memory, we've already tried replacing that, and I have no idea on how to go about testing the "suicide battery." Having the machine plugged in or unplugged makes no difference, if that's any help.
[QUOTE=Drumdevil;41683596]Hi, Bohb.[/QUOTE] Hi. Do you have a problem? [QUOTE=Drumdevil;41683596]OT: Isn't that CPU embedded on the mobo?[/QUOTE] Laptops have socketed CPUs just like desktop machines. [QUOTE=Big Dumb American;41689715]It's not the memory, we've already tried replacing that, and I have no idea on how to go about testing the "suicide battery." Having the machine plugged in or unplugged makes no difference, if that's any help.[/QUOTE] All laptops have CMOS batteries. They're usually smaller batteries than desktop CR2032s, and most of the time in irritating places to get to. You may have to partially or fully disassemble the laptop to get at it.
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