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brooksmosesSeveral months ago, I posted a comment on the This Is Broken weblog, noting my frustration with motherboard-mounted AC power jacks on laptops, and noting that I had fixed a couple of them by following some online directions. Since then, I seem to regularly be getting comments in this journal asking me to explain how I did it. Clearly I need to just write this up once and thoroughly, post it, and be done with it.
First, the keywords. My experience is with a Compaq Presario 1210 laptop (which is very similar to the 1600 series), and a pair of HP Pavilion xf235 laptops, but this should apply to most similar laptops; the advice is mostly generic.
The problem, in short, is that most laptops have their AC power jacks hard-mounted to the motherboard just like any other soldered-on component. But, unlike most other components, they regularly get yanked on when someone steps on the power cord or such, and eventually the solder joints (or the mounting tabs, which after all are pretty thin metal) start to fatigue, and eventually they crack. At this point, the laptop will only charge if the plug is twiddled "just so", and doesn't work reliably.
The official solution, of course, is to replace the motherboard -- which fixes the symptom, but not the overall design problem. On a laptop with a street value of $300, this is also not an economical solution. But it does mean that you don't really have anything to lose if you toast the motherboard trying to fix it yourself.
So. Enough preamble. Here's how I fixed the problem.
DISCLAIMER: THIS IS A DESCRIPTION OF HOW I DID THIS REPAIR. FOLLOW THESE INSTRUCTIONS AT YOUR OWN RISK, AND USE YOUR OWN JUDGEMENT; I MAKE NO WARRANTY THAT YOU WILL HAVE A WORKING LAPTOP WHEN YOU FINISH. SOME MINOR STEPS HAVE BEEN OMITTED.
On the Compaq, I used the solution that I found on http://www.delanoscientific.com/cpq1675.html. Essentially, you take a three-inch strand of some form of heavy-but-flexible two-conductor wire -- that site recommends a good grade of speaker wire, but I happened to have a dead iBook power supply that I salvaged some wire from -- and solder a socket on the end of it that matches the plug on the power cord, feed it through the original power jack hole in the case, and solder the other end to the motherboard where the original power jack used to be. One trick is to tie a knot in this new pigtail just inside the case, so that pulling on it only pulls on the knot, rather than pulling on the solder connections.
On the two HP Pavilion computers, I found a better solution. There is a hole in the case, right next to where the power jack goes, that's intended for a PS/2 keyboard or mouse plug. However, it's unused and blanked off, which makes it a great place to put a case-mounted power jack -- and it turns out that a standard 1/2"-diameter panel-mount jack fits perfectly. I used a Philmore No. 248 "DC Power Jack", which has 2.5mm x 5.5mm pin and socket diameters, thereby matching the original plug. While you're at the electronics shop, get a decent soldering iron and a power supply for it that lets you control the temperature. If you haven't done much soldering before, find some sort of discarded computer-board junk that you can practice on.
Here's what the new case-mounted jack looks like when it's installed; the original power jack hole is just to the left of it:
Actually doing the replacement took me about two hours, on the last one I did. The time-consuming part is that you need to completely disassemble the laptop to remove the motherboard. This starts (on the HP Pavilion computers) with gently popping out the panel above the keyboard that has the CD playback and volume controls on it, and continuing by removing every screw you come across. A digital camera is a very useful timesaver here; photograph the screwdriver pointing to every screw you remove, put the screw next to a number on a numbered piece of paper, and photograph it there -- then, go through the photos backwards and you have a detailed set of reassembly instructions.
When you have the motherboard all the way out, the next step is to remove the remnants of the old power jack, and solder on some one-inch-long wires (or the pigtail, if you're not using a case-mounted jack; remember to feed it through the case first!) in its place.
Here, it's worth noting that the original power jack has three pins, and acts somewhat like a switch. One pin goes to the ground, and becomes connected to the power-adaptor ground when the adaptor is plugged in to the laptop. The second pin is the +19.5V (or whatever the power voltage is) line; when the adaptor is not plugged in, it becomes connected to the ground pin. The third pin is a logic pin for determining when the adaptor is connected; it is open-circuit when the adaptor is not plugged in, and connected to the ground pin when it is.
This could theoretically be problematic with the pigtail-mounted socket, as that socket only has two connections -- the logic line for sensing whether the adaptor is connected does not exist. I simply ignored this problem on the Compaq laptop, and the computer seemed to work fine; it may or may not work properly on other computers. On the case-mounted jack, there are three lines, so this is not an issue.
Meanwhile, speaking of the case-mounted jack for the HP Pavilion laptops, there's the issue of attaching it in the case. Remove the blanking plate by appropriate means (I did this by grinding off the heat-swaged mounting pins), and install the jack in the hole that this leaves. You'll need to remove a bit of material from the inside top of the jack to prevent interference with the top half of the case later; now is a good time to do that. Also, if you want to be fancy, you can cut a small rectangle out of the blanking plate and superglue it in place to cover the old power-jack hole.
Anyhow, you then reinstall the motherboard (with its new wiring) in the case, and -- if using the case-mounted jack -- connect the wires to the jack. On the HP Pavilions, make sure the wires aren't over the LEDS immediately behind it on the motherboard; there are clear-plastic "light pipes" that have to go on top of those, and the wires can easily get in the way. Then reassamble the laptop, and that's "all there is to it".
First, the keywords. My experience is with a Compaq Presario 1210 laptop (which is very similar to the 1600 series), and a pair of HP Pavilion xf235 laptops, but this should apply to most similar laptops; the advice is mostly generic.
The problem, in short, is that most laptops have their AC power jacks hard-mounted to the motherboard just like any other soldered-on component. But, unlike most other components, they regularly get yanked on when someone steps on the power cord or such, and eventually the solder joints (or the mounting tabs, which after all are pretty thin metal) start to fatigue, and eventually they crack. At this point, the laptop will only charge if the plug is twiddled "just so", and doesn't work reliably.
The official solution, of course, is to replace the motherboard -- which fixes the symptom, but not the overall design problem. On a laptop with a street value of $300, this is also not an economical solution. But it does mean that you don't really have anything to lose if you toast the motherboard trying to fix it yourself.
So. Enough preamble. Here's how I fixed the problem.
DISCLAIMER: THIS IS A DESCRIPTION OF HOW I DID THIS REPAIR. FOLLOW THESE INSTRUCTIONS AT YOUR OWN RISK, AND USE YOUR OWN JUDGEMENT; I MAKE NO WARRANTY THAT YOU WILL HAVE A WORKING LAPTOP WHEN YOU FINISH. SOME MINOR STEPS HAVE BEEN OMITTED.
On the Compaq, I used the solution that I found on http://www.delanoscientific.com/cpq1675.html. Essentially, you take a three-inch strand of some form of heavy-but-flexible two-conductor wire -- that site recommends a good grade of speaker wire, but I happened to have a dead iBook power supply that I salvaged some wire from -- and solder a socket on the end of it that matches the plug on the power cord, feed it through the original power jack hole in the case, and solder the other end to the motherboard where the original power jack used to be. One trick is to tie a knot in this new pigtail just inside the case, so that pulling on it only pulls on the knot, rather than pulling on the solder connections.
On the two HP Pavilion computers, I found a better solution. There is a hole in the case, right next to where the power jack goes, that's intended for a PS/2 keyboard or mouse plug. However, it's unused and blanked off, which makes it a great place to put a case-mounted power jack -- and it turns out that a standard 1/2"-diameter panel-mount jack fits perfectly. I used a Philmore No. 248 "DC Power Jack", which has 2.5mm x 5.5mm pin and socket diameters, thereby matching the original plug. While you're at the electronics shop, get a decent soldering iron and a power supply for it that lets you control the temperature. If you haven't done much soldering before, find some sort of discarded computer-board junk that you can practice on.
Here's what the new case-mounted jack looks like when it's installed; the original power jack hole is just to the left of it:
Actually doing the replacement took me about two hours, on the last one I did. The time-consuming part is that you need to completely disassemble the laptop to remove the motherboard. This starts (on the HP Pavilion computers) with gently popping out the panel above the keyboard that has the CD playback and volume controls on it, and continuing by removing every screw you come across. A digital camera is a very useful timesaver here; photograph the screwdriver pointing to every screw you remove, put the screw next to a number on a numbered piece of paper, and photograph it there -- then, go through the photos backwards and you have a detailed set of reassembly instructions.
When you have the motherboard all the way out, the next step is to remove the remnants of the old power jack, and solder on some one-inch-long wires (or the pigtail, if you're not using a case-mounted jack; remember to feed it through the case first!) in its place.
Here, it's worth noting that the original power jack has three pins, and acts somewhat like a switch. One pin goes to the ground, and becomes connected to the power-adaptor ground when the adaptor is plugged in to the laptop. The second pin is the +19.5V (or whatever the power voltage is) line; when the adaptor is not plugged in, it becomes connected to the ground pin. The third pin is a logic pin for determining when the adaptor is connected; it is open-circuit when the adaptor is not plugged in, and connected to the ground pin when it is.
This could theoretically be problematic with the pigtail-mounted socket, as that socket only has two connections -- the logic line for sensing whether the adaptor is connected does not exist. I simply ignored this problem on the Compaq laptop, and the computer seemed to work fine; it may or may not work properly on other computers. On the case-mounted jack, there are three lines, so this is not an issue.
Meanwhile, speaking of the case-mounted jack for the HP Pavilion laptops, there's the issue of attaching it in the case. Remove the blanking plate by appropriate means (I did this by grinding off the heat-swaged mounting pins), and install the jack in the hole that this leaves. You'll need to remove a bit of material from the inside top of the jack to prevent interference with the top half of the case later; now is a good time to do that. Also, if you want to be fancy, you can cut a small rectangle out of the blanking plate and superglue it in place to cover the old power-jack hole.
Anyhow, you then reinstall the motherboard (with its new wiring) in the case, and -- if using the case-mounted jack -- connect the wires to the jack. On the HP Pavilions, make sure the wires aren't over the LEDS immediately behind it on the motherboard; there are clear-plastic "light pipes" that have to go on top of those, and the wires can easily get in the way. Then reassamble the laptop, and that's "all there is to it".
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no subject
Date: 2004-09-06 11:18 pm (UTC)no subject
Date: 2004-09-06 11:40 pm (UTC)(no subject)
From:socket for compaq
Date: 2004-09-08 11:50 pm (UTC)great article. do you have the part number for the socket you used to plug the ac adapter in for compaq notebook? Or anything that would help me find the "right" one.
Thanks!
Zachary
Re: socket for compaq
Date: 2005-02-02 07:38 pm (UTC)If the Compaq uses the same plug dimensions as the HP (and I have no evidence that it does, as I've long since given away mine, but it seems a likely guess), the appropriate part number would be a Philmore #258 "In-Line DC Power Jack".
Re: socket for compaq
From:Re: socket for compaq
From: (Anonymous) - Date: 2005-06-20 09:56 pm (UTC) - ExpandRe: socket for compaq
From:Re: socket for compaq
From: (Anonymous) - Date: 2005-06-21 11:04 pm (UTC) - ExpandRe: socket for compaq
From:Re: socket for compaq
From: (Anonymous) - Date: 2005-06-21 11:34 pm (UTC) - ExpandRe: socket for compaq
From: (Anonymous) - Date: 2005-06-21 11:37 pm (UTC) - ExpandRe: socket for compaq
From: (Anonymous) - Date: 2005-06-22 01:55 am (UTC) - Expand*BAD* QA -- no solder on power plug
Date: 2004-09-15 09:17 pm (UTC)Just thought I would put my 2 cents in...
EBo --
eBay caution...
Date: 2004-12-03 01:22 pm (UTC)Thanks for the page - it might save me from my no questions asked eBay purchase!
http://poconopcdoctor.com
no subject
Date: 2005-01-09 04:55 am (UTC)The metal pole that goes into my computer bent off, and now I am left with a laptop that is running on it's battery and dying as I am typing this. Thank god for our other computer. I don't know how to fix this, any ideas?
Thanks!!
Same Issue with a ze1250
Date: 2005-01-25 12:16 am (UTC)may be there are other people who could use this.
Great Article!!
Re: Same Issue with a ze1250
From:Re: Same Issue with a ze1250
From: (Anonymous) - Date: 2005-03-14 12:53 am (UTC) - ExpandRe: Same Issue with a ze1250
From:(no subject)
From:(no subject)
From:(no subject)
From:Electronic Tech
Date: 2005-01-26 03:00 pm (UTC)Re: Electronic Tech
Date: 2005-02-02 08:13 pm (UTC)You make a valid point, though: if trying this sort of thing would cause one to have undue worry, it's probably best to take the laptop to a repair shop and pay someone else to worry.
Hello i have the hpze1115
Date: 2005-01-30 09:01 pm (UTC)Heres my problem i soldered it on and now my comp will act like its gonna start up (battery charging light is on and power light comes on) then just sit idle :( i tried hooking it up to a standerd monitor to see if something was wrong with lcd screen but no picture that way either??? Am i doing something wrong can u tell me how u hooked urs up?? or did i screw up motherboard =(
Re: Hello i have the hpze1115
Date: 2005-02-02 07:59 pm (UTC)Does it work if you have the battery charged and the power plug not plugged in? Having the jack hooked up wrong shouldn't affect whether that works, so that's one way to test it. If it still doesn't work then, you've probably damaged something else somewhere -- or possibly just not hooked something up right when you were putting the rest of it back together. Maybe try taking it apart and putting it back together, and see if that helps?
For that matter -- the batteries have a little display on the side that you can use to tell if they're charged. Does letting it sit with the battery-charging light on for a while cause the battery to get charged? Does the battery-charging light eventually go off? If those happen, that's also an indication that you hooked things up right.
Beyond that, I don't know. Sorry.
HP Pavillion Jack(ed)...
Date: 2005-03-01 12:30 pm (UTC)I've soldered the live, ground and switch wire to the power connector. At first I could see an arc when attaching the AC, so I took out the switch wire. It now charges the battery, and the laptop comes on!! :)
The problem is that it only stays on for 30 seconds, 100% of the time with both the battery and AC. I can get into the BIOS, but it still switches itself off after 30 seconds. Also tried bootdisk from CD, same problem. It looks like everything else is in working order: CPU, Memory, CDROM...just keeps cutting out.
Any ideas? Could the switchwire have been connected to the incorrect polarity? One other thing I've noticed is that when its on AC, the power and the battery light shows charging (as it would normally). But when its on battery power, it shows that its powered up but the battery light does not illuminate. I'm at a loss...!
Re: HP Pavillion Jack(ed)...
Date: 2005-03-06 12:22 pm (UTC)Re: HP Pavillion Jack(ed)...
From:Re: HP Pavillion Jack(ed)...
From:Re: HP Pavillion Jack(ed)...
From:Re: HP Pavillion Jack(ed)...
From: (Anonymous) - Date: 2009-01-01 04:28 pm (UTC) - Expandhelp.
Date: 2005-03-02 12:19 am (UTC)Re: help.
Date: 2005-03-14 01:24 am (UTC)Anyhow, yes, you would take off the rest of the power jack that's still attached to the board, and solder on the replacement. Definitely, if you haven't done this sort of thing before, find a piece of circuit board out of some broken electronic thing (a clock-radio would probably work well, or a no-longer-working computer), and practice taking off parts and putting them back on.
Excellent POst!
Date: 2005-04-08 12:33 pm (UTC)After removing the motherboard, my existing connector was cracked, but still had 2 good solder joints - the third connector was just a broken solder joint. I probably could have resoldered this and all would have been well, but I figured I would be doing it again soon. Anyway, I removed the old connector by de-soldering the 2 good connections. By doing this I preserved the existing connector (crack included!). This allowed me to connect my power supply to the removed connector and using a power tester was able to determine which was the +19v pin, the common and the switching pin. I then labled these A, B, and C on a diagram. I then repeated the process with the new connector (and yes a Philmore 248 is perfect) which allowed me to 'map' the pins to the solder joints on the motherboard. I also took the time to trim down the wires on my 3 new leads and flatten them using pliers - this allowed them to slip through the motherboard just as the original pins on the broken connector had. I could then let the solder flow from the underside by placing the soldering iron on the top side (touching the wires) and the solder on the underside.
Again, Thanks for the advice and the GREAT instructions!
Thanks
Date: 2005-04-16 01:45 am (UTC)- Adam
Re: Thanks
Date: 2005-06-07 02:28 am (UTC)My girlfriend has a ZE4315, which also had (has) the power jack issue. Her parents took it to several computer stores over the past 6 months, now with the warranty expired, I asked if I could have a look at it, about 2 months ago. I managed to solder it back down and it worked solidly until now, my girlfriend has been very careful with the laptop since, but it seems to have just died properly this time (I have spent a good 8 hours looking at it, soldering it, un soldering it, wiring it, looking on the net for similar topics, etc.) I am thinking the best option is to find a docking bay, as I'm not sure if it's only the jack, or the section of the motherboard (everything else still works fine from battery.) What strikes me, is I own a ZE4133, and I opened it up to have a look at how the jack should be mounted/soldered, and I found that my jack has NO wiring, or soldering whatsoever, its just sitting there, yet my girlfriend's has/had some tacky looking wire coming out of the back, which was soldered into the motherboard. If anyone has a similar model with the same connection, would it be possible to get a photo? I'm sure I wired it up with some fresh wire, the way it was, but now there's nothing at all (until now my girlfriend had to spend 10 mins or so moving the cable until it was in a good position.)
I would be very grateful for any tips, photos, advice anyone may be able to provide.
too many socket configurations!
Date: 2005-08-20 06:18 am (UTC)Anyway, after soldering on, and closing up the computer, it attempted to boot several times, would run for a while, no screen though. Then it was dead. I opened up, straightened out some pins on a cable that runs to the screen (they were bent and weren't plugged in!) and closed it back up. Didn't work at all. Figured I killed it, but now reading, thinking it might have been a heat sink issue? Any advice on where to find some directions on this stuff? I am a novice, and this is stretching it!
The fun part was I decided to switch polarity and see what happened (it's almost 2 years old, and this isn't the first repair). I reversed the wires and plugged in. The adapter got warm, starting to get hot! the wires got warm. The battery was still in ... and obviously something was drawing current. Not unlike the old days, actually. My adapter used to get burning hot, as did the jack. When unplugging, you could actually get burned. I don't think laptops should run that way, and I'm figuring I always had some problem in the power jack. So curious as to why it's working or drawing current with poles reversed. I just don't know enough and can't find information on laptop repair/motherboards etc. Any suggestions?
In all seriousness, I am trying to see if it has life left in it cuz I don't want to buy another, and I'll just settle on my desktop, much as I hate to. Any way of reading the board before closing to see that it is functional? Not sure what part actually dies when the MB goes, but any indications? any way of testing?
Also, fyi, there is a patent on those darn right-angle plugs! You'd think they actually did something useful?
Thanks for any help. And a good site, by the way. Wish I saw this earlier!
I did the "Montana Fix" on a Compaq 2100
Date: 2005-09-21 04:26 pm (UTC)Anyway, the upshot is for the total sum of $1.99 for the trailer hitch connection(no sales tax in Montana) I was able to fix a laptop that I was ready to throw away. Thanks for the help on this!!
Re: I did the "Montana Fix" on a Compaq 2100
Date: 2005-10-04 01:28 pm (UTC)Re: I did the "Montana Fix" on a Compaq 2100
From: (Anonymous) - Date: 2005-12-05 07:33 pm (UTC) - ExpandCompaq presario 2500
Date: 2005-09-23 06:38 pm (UTC)Thanks for all of the tips and advice. I'm sure they will come in handy as we embark on this project.
Compaq
Date: 2005-10-03 08:20 pm (UTC)Re: Compaq
Date: 2006-06-08 12:21 am (UTC)As for burning out the middle layer -- I've heard that, too, and suspect in general it's true. This is probably another area where the power jack is "safer" than most of the motherboard; I don't think there are usually any particularly delicate traces in that part of the board. But being very careful is certainly a good thing!
Silkscreen Image
Date: 2005-10-19 04:29 pm (UTC)Compaq Presario 2175US
Date: 2005-11-05 05:20 am (UTC)My question is: Why is it that we should not hold Compaq accountable for owning up to THEIR problem? Hundreds of companies issue recalls for faulty or potentially dangerous items, and the repairs/replacements are issued free of charge. Some companies offer the recalls or repairs voluntarily, and others by mandate of government orgs like the FCC, FTC, etc.
Based on everything I have read here and in 5 other forums, I think there is enough evidence to proove a pattern of poor manufacturing, which regardless of warranty, should be addressed at the manufacturer's expense. What do you all think? Any ideas for action?
George
libertyordeath@techtotal.com
Re: Compaq Presario 2175US
Date: 2005-11-05 06:02 am (UTC)The problem with trying to request a recall on it is that it's an industry standard design using standard off-the-shelf parts. For instance, note that I had problems with a Compaq and two HPs, all of which were pre-merger and thus from unrelated companies. And it's something that takes a few years of heavy use before it shows up; the manufacturers could make the reasonable argument that their laptops are not intended to last that long.
Re: Compaq Presario 2175US
From: (Anonymous) - Date: 2005-12-07 04:51 am (UTC) - ExpandCompaq 2135US fixed
Date: 2005-11-21 06:05 am (UTC)I just wanted to say thanks for having this up. I had no idea what was going wrong with my plug until a friend mentioned he had the problem on hs Compaq and I found your site by googling. Well long story short I took the machine apart and found a crack in the solder on the DC jack so I removed the jack and soldered on a case mount part I purchased for $1.50. Saved myself a whopping $300 with only 4 hours of work.
:)
Re: Compaq 2135US fixed
Date: 2005-11-26 07:21 am (UTC)thanks,
daniel
Re: Compaq 2135US fixed (NX7000 here)
From: (Anonymous) - Date: 2006-02-27 04:55 am (UTC) - ExpandThanks!
Date: 2006-05-27 06:31 pm (UTC)Re: Thanks!
Date: 2006-06-07 02:45 am (UTC)no subject
Date: 2006-06-07 02:43 am (UTC)no subject
Date: 2006-06-07 11:22 pm (UTC)no subject
Date: 2006-06-08 12:21 am (UTC)In my experience, the point of failure is usually that one of the tabs will break, right at the surface of the motherboard. Since that's actually broken rather than dislodged, you can't really fix it by resoldering. (You could do a sort of kludge by soldering across the break, but it would be pretty fragile and wouldn't last long.)
I have, occasionally, seen a tab that is intact but has broken loose from the solder around it. (This is quite obvious if you look at the back side of the motherboard, since you can see the tab loose in a hole in the solder.) In that case, resoldering it would work.
Anyhow, since the jack stops working when just one of the tabs breaks, the other two are still holding it on the motherboard, so it wiggles but is still firmly attached. You can remove it either by melting the intact connections with a soldering iron and pulling it out, or by clipping the remaining tabs with some sort of small wire cutter (and then using the soldering iron and needlenose pliers to get the cut-off bits out of the holes). In either case, practice the un-soldering part on some scrap electronics until you're confident in your abilities -- this is something that takes practice to do without damaging things.
(no subject)
From: (Anonymous) - Date: 2006-06-08 01:57 am (UTC) - Expandno subject
Date: 2006-06-28 01:52 pm (UTC)Wire Configuration?
Date: 2006-08-13 02:25 am (UTC)Can anyone help with this?
TIA! Anything would be very very appreciated.
Re: Wire Configuration?
Date: 2007-08-01 03:45 am (UTC)Small Problem
Date: 2006-08-16 07:02 pm (UTC)any ideas?
Presario 705 DC jack
Date: 2006-08-30 04:15 pm (UTC)The DC jack was faulty for a while before I realised the problem and has burnt a small area of the board around the bottom leg. It may also have damaged a nearby capacitor C505. Does anyone have a circuit diagram for this area of the board or a photograph of this area on a board that is undamaged? I can't find one anywhere but with information I think I could fix my computer in much the same way as your article describes as I think everything else works just fine. Many thanks in advance for any help!!
Antonia
Re: Presario 705 DC jack
Date: 2006-11-24 10:49 pm (UTC)