I've made a mistake somewhere rebuilding my acer aspire 5551 laptop.
A little while ago the DC jack was damaged by a fall, I opened up the laptop to establish that a loose connection had occured at the jack, the laptop was working fine otherwise as I was able to start it by jiggling the wires. So, I ordered a new jack with the cable that plugs into the motherboard.
Of course getting this cable in requires completely removing the motherboard from the laptop, I was quite confident but I still sought out a disassembly guide, plugged in the cable reassembled the basic components to test charging the battery, battery charge light on - great.
Completely reassembled the laptop - problem, the laptop turns on, the screen lights up, CPU fan comes on, moments later it turns itself back off, nothing is displayed on the screen in the time it is lit.
Any suggestions? Ive made 3 seperate complete disassembly's and reassembly's with no joy.
"The world is a temple to the self, and these days, there's alot of believers"
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There are certainly other possible causes (e.g. a component failure you somehow introduced during the disassembly/re-assembly procedures (i.e. ESD damage)) but here's where'd I'd start if it were mine...
That's the way my laptop acts when it thinks the battery is too low to power the unit for any length of time...when I'm not connected to AC.
But, if you're on AC when that happens, it suggests it's not recognizing that fact and it's not sensing the battery status properly (or the battery has failed since the last time it all worked properly). Since the battery charging LED is on, one would think it should recognize you're on AC power and one would think it should work. All the laptops I've owned have always worked off the manufacturer's AC adapter even with the battery removed.
When on battery only and it does the same thing, then it could be just the battery status is being improperly interpreted or battery has failed.
I've never had one like this...but I've read that some laptops don't work on AC when there is no battery or if the battery is 100% depleted. People said they had to wait until the battery charged up to X% (e.g. 10%) before the laptop would power-up.
My thinking is the odds are with a possible sensor/connector problem. Also make sure that any inter-board ribbon cables within are completely and properly seated as well. I've seen some ZIF cable connectors that were too easy to pull-apart while disassembling a laptop even with the connector-cable lock engaged.
In your handling of the Mobo, you may have accidentally broken the contact between the processor, and or GPU heatsink which will cause the machine to start up for about 8 to 10 seconds and then turn off, sometimes you dont even have time to see any indication on the screen that you even powered on the system before shutting down, I have had this happen on several makes and models, try removing the heatsink, cleaning the old heatsink compound off of the CPU and the heatsink, then put on new heatsink compound making sure to be generous, If your GPU,(graphics chip), is also cooled by the heatsink, then repeat the procedure with it also.
You are not saying that you are recieving any beep codes, so I am suggesting this first.
Hopefully this will alleviate your problem. GPU's are EXTREMELY succeptable to heat and will shut down your system within seconds of detecting a thermal overload.
Hopefully this will help.
Before going through the fairly high-risk procedure of removing and reinstalling a laptop CPU, I'd check that any removable memory modules are properly seated. If more than one module, also try booting with one at a time in the primary slot. I'd even try testing the memory in another laptop before I tried dealing with the CPU.
Bad or improperly seated memory can cause unpredictable boot-time symptoms, including "no beep codes".It's certainly easier to check rule out, and faster and less risky than dealing with the CPU. Remember to use proper ESD handling, and AC and DC power-removal protocols while handling an open laptop.
Thanks for the replies guys, RAM is a no brainer and the first thing I checked. Self caused damage, possible, I'd like to think I was careful enough having removed motherboards in the past, but its always a possibility, I'll get back to you in a few days to let you know how I get on.
"The world is a temple to the self, and these days, there's alot of believers"
Okilly dokilly, Yes I suppose you would check memory seating first, common knowledge, But even completely removing the memory module will not under just about any circumstances cause the computer to turn off, as was the behavior stated, But hey, what do I know LOL, I've only been working on computers since before even windows 3.1 was released, But Obviously I know not what I am speaking of, Deleting my account right now. NOT! theres no "high risk" in removing a ZIFF socketed processor as long as you dont use a hammer to do it. Not trying to be a smart alec, was just making LOGICAL suggestions to get the gentlemans laptop fixed., There are effective ways to disagree with anothers suggestion without feeling the need to exaggerate.
Edwin Meyer said:...NOT! theres no "high risk" in removing a ZIFF socketed processor as long as you dont use a hammer to do it. Not trying to be a smart alec, was just making LOGICAL suggestions to get the gentlemans laptop fixed., There are effective ways to disagree with anothers suggestion without feeling the need to exaggerate.
Edwin Meyer said:...try removing the heatsink, cleaning the old heatsink compound off of the CPU and the heatsink, then put on new heatsink compound making sure to be generous, If your GPU,(graphics chip), is also cooled by the heatsink, then repeat the procedure with it also....
I responded based on your specific advice included in that answer that the processor heatsink(s) be removed, cleaned, and re-applied. I also believe that your telling people there is "no 'high risk' " and "as long as you don't use a hammer to do it" are significant exaggerations. The difference is that telling people there's "no 'high risk' " can have potentially disastrous or costly results by providing a false sense of security which may encourage people to take shortcuts and/or not adequately educate themselves in the details and/or practice on how to perform such procedures.
As you can see, I do strongly disagree with you regarding the degree of risk associated with this...especially heatsink removal/re-install actions on the processors. This is the basis for my rather detailed response.
I believe these procedures are of such a risk level that people shouldn't go in with a false sense of security. I believe it is a mistake and irresponsible to tell people there are no risks in any repair action on laptop processors. Doing so only leads to under-informed decisions and actions and gives low-experience or non-skilled people a false sense of confidence that can destroy a potentially $1000 investment with one mistake.
To further reduce risks, they should also first practice these types of procedures on at least one "junker", before risking an important and/or expensive laptop. It's their choice of course, but it should be based on more detailed information.
While the risks can be reduced, they remain relatively high compared to just about any other repair action on a laptop (excluding anything requiring soldering, disassembling/reasssembling an conductive polymer strip connection for cables or displays (where the usually transparent contacts are just a few hundred atoms thick), etc). In addition to the mechanical issues, the user is also potentially needlessly exposing all the electronics in the laptop to direct ESD. That's something many people ignore entirely, even those who should know better and are trained in ESD reduction methods (and then they wonder why their system has "unexplainable" or "different" errors...even after the original failure has been repaired)
I've read of and personally seen a number of cases in which even highly skilled people have ripped the top casing off a laptop processor while attempting to remove the heatsink. Sometimes the manufacturer used an epoxy-based thermal compound, but sometimes even "grease" thermal compounds dried out and ended up strongly gluing the heatsink to the processor's case. The risk is substantially lower when the manufacturer instead uses a thermal conductive pad. Unfortunately, one often can't tell which was used until the heatsink is removed. Thermal pads may not be used by a manufacturer as the pads are significantly less effective in conducting heat from the processor to the heatsink and the processor "runs hotter" as a result.
Also, some manufacturers make getting to the CPU very difficult. Depending on the laptop design the risk can be quite high that a person will damage something else simply while trying to gain access to the processor(s)...whether or not the processor itself uses a ZIF socket is irrelevant.
You are also assuming the CPU/GPU has a ZIF socket. Some people won't understand what that means and based on the "no 'high risk' " statement, they may try to remove the heatsink only to accidentally rip the processor off the motherboard (or damage the processor's now exposed silicon chip as well). ZIFs are not universally used in laptop motherboards.
OK, I am willing to accept your comments on the processor, and I suppose I was remiss in omitting the information reguarding the heatsink removal process, which can in select circumstances damage the top of your CPU, The question though was posed by someone who appears at least somewhat familiar with the disassembly of a laptop, and the componants within, and therefore not a "novice" . Certain types of compounds can in fact "glue" the heatsink to the processor head, and once again based on his ability to physically dissassemble the laptop and reassemble it without problems (other than the problem in quesation), I " assumed" the questioner was at least a layman in this instance.,(ok, as Benny Hill said, Never Assume"). but my original diagnosis still stands. As I stated before, you can remove both the processor AND the memory and the laptop will still not shut itself down as described, The shutdown feature is a built in feature on most laptops as a safety device when high heat is detected in order to avoid doing damage to the processor or GPU. Proper memory however, unless severely damaged, will NOT under ANY circumstances that I am aware of shut down the computer completely at boot.
So in conclusion, I offer my apology for my poor choice of words while I still stand by my probable diagnosis.
Bottom line is that debugging the memory is much safer to the computer, faster, easier, and cheaper to perform and rule-out than removing and reinstalling processors and heatsinks (high quality thermal compound isn't cheap). I also believe a memory subsystem issue is far more likely than a processor issue. Just the fact that memory is customer accessible and more often handled by a human user (skilled or unskilled) than the processors makes them more vulnerable and more likely to be damaged or incorrectly installed. If I recall correctly, when I first mentioned memory debugging, Jon had not yet indicated what, if any, memory subsystem debugging he had performed. Hence my suggestion regarding the debugging. Thus, it was illogical to go through the complex (and in my opinion highly risky) removal and reinstall of the processors before easily and quickly ruling-out the memory subsystem as a possible cause. Once that is done, it then makes sense to go after the suspects that are generally less likely and more difficult and time-consuming to debug.
Edwin Meyer said:...The shutdown feature is a built in feature on most laptops as a safety device when high heat is detected in order to avoid doing damage to the processor or GPU. Proper memory however, unless severely damaged, will NOT under ANY circumstances that I am aware of shut down the computer completely at boot.....
Well, to be fair, I was at first responding to your comment about why your first suggestion was to go to the processors when there weren't any beep codes.
Edwin Meyer said: You are not saying that you are recieving any beep codes, so I am suggesting this first....
You are correct about one common shutdown protocol on overheating processor(s), however, firmware can be written to shutdown the computer in the event of a number of additional different faults detected during boot diagnostics, whether or not memory module(s) is present. Naveen Goud suggested a couple other scenarios (like a damaged motherboard or power issue), and as you suggested, even "severely damaged" memory modules could result in a shutdown as well.
My experience has been that faulty/damaged memory subsystem or incorrect memory module (or pci-bus card) installation, is responsible for many reported boot problems. Memory subsystem associated fault symptoms can present as virtually anything, including "no beeps", unexplained display behavior, system shutdown, and more.
Edwin Meyer said:
And by the way, the Acer Aspire 5551 does in fact have a ZIF socket as opposed to a soldered embedding.
I added that last paragraph in the relevant post to simply address the general case for completeness, and to not assume a ZIF socket was used. My comment about ZIF sockets was to cover the potentiality that a given version of a motherboard may or may not use a ZIF socket. I've seen major design differences in motherboards used in the same model of a computer, including the absence or presence of sockets for various components. Initial production run and cost-reduction redesigns can result in significant variations in motherboard design over the life of a particular model of computer. I've been bitten on the butt a number of times by making assumptions...and will be again, I'm sure.
...Ive made 3 seperate complete disassembly's and reassembly's with no joy.
A bit of expansion on my first post.
Not that one more disassembly/reassembly wouldn't be painful, but did you check the continuity and voltages of ALL the battery contacts from the battery contacts themselves to the ultimate termination point of that connection? (e.g. from arbitrary battery contact "A" to arbitrary sub-daughter board "pointX"). Some batteries for example have N contacts, while others might just have 3. The 3rd - Nth contacts may be either sensor or sub-voltage connections. Obviously one would assume that all connections need to be intact from the battery to any circuitry. Each battery contact may also have to go to more than 1 connection. For example, I've got one laptop where one of the battery contact wires is later split and goes to 2 different circuit boards. Unfortunately, you might need a known good battery to compare measured values.