Ric_ Posted June 23, 2009 Posted June 23, 2009 We've (Stu and I) come across a strange problem. A laptop trolley contains 30 identical HP nx6110 laptops running Windows XP. 4 of these laptops have recently developed a problem where by they hang at POST. If you tilt the laptop, it will continue to boot... stopping the tilting causes it to hang again... etc. We tried the usual stuff: Re-image: hangs during re-imaging Hardware (memory, hard disk, etc.) test: all come back OK Re-seating every component: this took a while! Re-setting the BIOS options: didn't do anything Removing combo drives (which have had their lasers prised out by the little darlings!): nothing What else can we try? Do we just need to start writing these off?
stu Posted June 23, 2009 Posted June 23, 2009 What else can we try? Do we just need to start writing these off? I personally think laptop Jenga
dalsoth Posted June 23, 2009 Posted June 23, 2009 If they work when you tilt them does that not indicate that it may be something physical that is causing the problem. First thought was a dodgy hard disk causing them not to boot but then that would not stop them posting would it. Perhaps some connector is not physically pushing up properly in the innards that connects when you tilt it? Maybe take the casing off and try to prod and poke things at post to see if you can narrow the search. Maybe a CMOS battery not connected properly when not tilted? Really weird one.
stu Posted June 23, 2009 Posted June 23, 2009 If they work when you tilt them does that not indicate that it may be something physical that is causing the problem. First thought was a dodgy hard disk causing them not to boot but then that would not stop them posting would it. Perhaps some connector is not physically pushing up properly in the innards that connects when you tilt it? Maybe take the casing off and try to prod and poke things at post to see if you can narrow the search. Maybe a CMOS battery not connected properly when not tilted? Really weird one. Have stripped all the casing off and (I squeeze ric tilts same effect) squeezing the region around the touch pad it starts running again then when you stop squeezing it stops have looked at bored for visible damage and cant see anything and all connections are firmly secured. (then rebuilt just to be sure my poking and squeezing didn't inadvertently fix it and it is still faulty.
witch Posted June 23, 2009 Posted June 23, 2009 I agree that it is probably a physical cause - perhaps some little darlings were carrying them all in a pile back to the lapsafe and dropped the lot. Have you looked at the battery? Do they work OK on AC power without the battery? I did have one with a dodgy battery connection but it was fine if the battery just wasn't there
Ric_ Posted June 23, 2009 Author Posted June 23, 2009 @witch: Removing the battery didn't help I was wondering if they had been dropped but I would have expected at least one to be marked Maybe HP just built in an EOL date?
stu Posted June 23, 2009 Posted June 23, 2009 Maybe HP just built in an EOL date? Pretty sure that would be illegal, and if they had been dropped what is the chance of all 4 having the same fault even if there was a sign of damage, and if a pile were dropped the bottom laptop should show considerably more damage than the top
pete Posted June 23, 2009 Posted June 23, 2009 Eyeballed the motherboard for stress cracks / lines? Are the mounts for the motherboard all ok? i.e a friction-fit connector out of place due to a plastic nub being broken?
Ric_ Posted June 23, 2009 Author Posted June 23, 2009 Eyeballed the motherboard for stress cracks / lines? Are the mounts for the motherboard all ok? i.e a friction-fit connector out of place due to a plastic nub being broken? They look fine inside (and outside for that matter). Moe ideas anyone?
Batman Posted June 23, 2009 Posted June 23, 2009 We had the exact same problem, same model, same fault. I dismantled the laptop and checked over the board and while I couldn't find any visible problem with the board itself (and I do know what I'm looking for), I did find what looked like a small piece of a paperclip close to the battery connector which I imagined might be causing the problem by shorting the connectors. In reality this was a red herring and I've still never figured out what was wrong with it. But then for us it's a one off, if you've got four with the same fault it's no joke. I suspect you may end up discarding them. Do the usual, re-seat memory, cpu, all cables etc. Also, I've seen some weird stuff caused by duff batteries. Try using it with a battery from a known good laptop, see if that makes any difference.
alextreadwell Posted June 23, 2009 Posted June 23, 2009 We had a tower computer once built buy some random company bought before i started work for the school and it developed a problem like that but it would only boot if you pressed your finger on the top left corner of the case? There was nothing near where you had to press only the cd drive we had a an idea that it was an earth problem and when we touched it we earthed ths case we changed power supply but there was no difference spent weeks on it and ended up chucking it. A few weeks later another 2 computers did the same thing we ended up swapping everything out of another same type computer and it was never fixed it always had the same problem ended up telling staff to stand with there finger on the tower while it booted up and replaced them as soon as we had the cash. Dosn't help much but could make some stickers tilt until booted
stu Posted June 23, 2009 Posted June 23, 2009 We had the exact same problem, same model, same fault. I dismantled the laptop and checked over the board and while I couldn't find any visible problem with the board itself (and I do know what I'm looking for), I did find what looked like a small piece of a paperclip close to the battery connector which I imagined might be causing the problem by shorting the connectors. In reality this was a red herring and I've still never figured out what was wrong with it. But then for us it's a one off, if you've got four with the same fault it's no joke. I suspect you may end up discarding them. Do the usual, re-seat memory, cpu, all cables etc. Also, I've seen some weird stuff caused by duff batteries. Try using it with a battery from a known good laptop, see if that makes any difference. i did notice that where i was squeezing there was an intel chip but couldn't see any signs of duff joint or anything of the sort. not sure what it was for it was seated directly below the touch pad, Ric reckons it was either the north / south bridge or graphics related.
dalsoth Posted June 23, 2009 Posted June 23, 2009 Perhaps try swapping each possible component with another working laptop and then perhaps even the working motherboard into the faulty casing. Perhaps it could be something like the case pinching something.
ozzy Posted June 23, 2009 Posted June 23, 2009 If you tilt the laptop, it will continue to boot... stopping the tilting causes it to hang again... what about cutting two of the table legs shorter then you have a tilting table, laptops boot:D no stress for you two everyone happy. Sorry I could'nt resist it
stu Posted June 23, 2009 Posted June 23, 2009 We had a tower computer once built buy some random company bought before i started work for the school and it developed a problem like that but it would only boot if you pressed your finger on the top left corner of the case? There was nothing near where you had to press only the cd drive we had a an idea that it was an earth problem and when we touched it we earthed ths case we changed power supply but there was no difference spent weeks on it and ended up chucking it. A few weeks later another 2 computers did the same thing we ended up swapping everything out of another same type computer and it was never fixed it always had the same problem ended up telling staff to stand with there finger on the tower while it booted up and replaced them as soon as we had the cash. Dosn't help much but could make some stickers tilt until booted lol good stoy but its the kid laptops so they would read all kind of instructions in that
Batman Posted June 23, 2009 Posted June 23, 2009 i did notice that where i was squeezing there was an intel chip but couldn't see any signs of duff joint or anything of the sort. not sure what it was for it was seated directly below the touch pad, Ric reckons it was either the north / south bridge or graphics related. Sounds like a BGA problem. Fairly common on boards these days, the chip is soldered to the board by a special machine using tiny blobs of solder instead of pins. If you get a dry joint it can cause problems, often putting some pressure on the right spot can be just enough to get the contacts together so that is works. This is very common on G3 and G4 Apple iBooks... a lot of people have made shims to go in the case to put pressure on the chip, or even clamped the iBook to the desk with G-clamps. It keeps the laptop going for a while but it's never a permenant fix. I did repair a tft monitor using a similar technique recently. This fine example is the pyromaniac's solution I think 1
SYNACK Posted June 23, 2009 Posted June 23, 2009 Heard about using a heat gun to rejoin these chips from an hp printer engineer (designer) who was one of my lecturers. This problem is indeed common if the joins are not just right.
Batman Posted June 23, 2009 Posted June 23, 2009 Yes, I used to use the same technique in my old job doing pcb repairs (my boss wouldn't pay out to repair the BGA machine so I never got to use it ). All great when it works but if you get it too hot you end up with a giant lake of molten solder underneath the BGA chip...
K.C.Leblanc Posted June 23, 2009 Posted June 23, 2009 You could redeploy them to a building with subsidence or issue them to all your one legged students.
Ric_ Posted June 23, 2009 Author Posted June 23, 2009 @Batman: That link is amazing! The only problem is that I now need to beat stu to work or risk the building burning down! Anyway... now to think of a suitable metallic weight to apply pressure whilst I warm one up with the blow-torch fitting on the soldering iron (I always wondered what I would use that for ). I've got nothing to loose after all
Batman Posted June 23, 2009 Posted June 23, 2009 You shouldn't need to apply pressure particularly, and you shouldn't need too much heat either. I have this image of someone squeezing a cream cake and it all gushing out of the sides in my head... that's not exactly what happens but it won't be pretty if you do mess it up. I would seriously suggest trying a shim for it first if you can because the mess is irreversible if the heatgun technique goes wrong! Sorry if that's too much warning for one post, I just don't want any laptops to get hurt
Ric_ Posted July 1, 2009 Author Posted July 1, 2009 @Batman: We completely ignored you and found a fix for the 'problem'. Enjoy... Fixing a HP nx6110 EDIT: Also see http://blip.tv/file/2307490/
buzzard Posted July 1, 2009 Posted July 1, 2009 loving the "tidy" desk whislt using a blow torch! I love Stu's hand about 1:40 sheilding the heat 1
stu Posted July 1, 2009 Posted July 1, 2009 (edited) I was shielding from the air con to see if it would work better Edited July 1, 2009 by stu
john Posted July 1, 2009 Posted July 1, 2009 Woo Glad it worked, maybe when we get 10 minutes of spare time we shall give it a go with some of ours, but need to buy a nice shiny new Iron first, I think i'll go for a nice Nimrod one again
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