03.18.06
Fixing AC power plugs in various HP and Compaq laptops
(This is a slightly-edited repost of an article I wrote elsewhere, back in 2004.)
Some time ago, I posted a comment on This Is Broken, 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. Several people asked me to explain further, and I decided it would be useful to write up a more detailed explanation of how I did it.
First, the keywords: My experience is with a Compaq Presario 1210 laptop (which is very similar to the Compaq 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, and for many of them this is the only structural connection. Unlike most other components, though, power jacks regularly get yanked on when someone steps on the power cord or such, and 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” (if at all), 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 on other versions of the laptop. 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. (Unfortunately, I didn’t keep a record of which pin goes with which connection to post here; sorry.)
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 from the case 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”.
In comments on the original version, someone mentioned that http://www.laptopjacks.com sells exact replacements for the original laptop power jacks, if you want to go that route, though they’re rather more expensive than the generic parts. Other people mentioned repairing the following laptops (which I’ll list for the sake of Google) with this advice: HP Pavillion 1150, Compaq Presario 1685, HP ze1115, HP xt412, HP Pavilion ZE43xx series, Compaq 2195US, and a Compaq 2100. I’m particularly entertained by the fellow from Montana with the Compaq 2100; he couldn’t find the right replacement fitting, and so ended up using a trailer-hitch plug set from the local truck stop.
Werner Heuser said,
October 24, 2006 at 1:54 am
This guide is listed in the Repair4Laptop: laptop and notebook upgrade and repair survey.
George said,
January 2, 2007 at 11:40 am
How do I remove the motherboard from the case of my HP notebook so that I can get underneath it and check the solder joints on the AC adapter? I have everythng apart and the motherboard is exposed. I have removed every possible screw from the top side of the motherboard. Still, the motherboard seems stuck. Once I have all the screws removed form the exposed motherboard, how the heck does it come out?
Thanks…
George
tekmanic@hotmail.com
Brooks said,
January 9, 2007 at 1:38 am
George: I don’t remember having any problems with this, although there may have been a bit of thermal tape or something near the floppy drive, and it’s a little complicated to work the motherboard out from around a few things. However, I’m nearly certain that it should be reasonably loose once all the screws are out. Perhaps you’ve missed one? I do remember that some of them are a bit camoflaged and easy to miss….
In particular, there are some screws holding the LPT port and other ports to the back of the case, if I’m remembering correctly. Another thing that could be catching is the “eject” buttons on the PCMCIA slot.
DJ said,
February 27, 2007 at 1:51 pm
Recently my Compaq Presario 1800US died. And I found the cause of this to be, you guessed it, the power jack. Every time I would plug in the laptop, I would get that electrical burn sort of smell. I dissassembled the entire laptop and got to the mother board. I plugged in the power adapter to the jack just to see what was happening with it. There were small sparks being emitted from the very back of the jack, where it connects to the motherboard itself. I then unplugged it carefully removed the old jack and soldered in the new one that I purchased. Although, it doesn’t spark and smoke as it did before. There is a small bit of spark within the circuit board, and the light on the power adapter flashes when its plugged in. The board also makes a bit of a click click noise. There has to be a short somewhere right? Any clue on what the problem is and how I could fix it? Thanks a lot.
-DJ
Ramos said,
March 30, 2007 at 8:38 am
Robert : I have a hp N5415 & I replaced the dc jack on the mother board,
& the plug on the power supply.But my labtop still does not turn on.
but i noticed that my power supply when disconnected,the green LED
is solid green.but when connected it blinks repedly orange.
i have doughts if its a short in the mother board or the power supply.
does any body have any suggestions.
JC said,
April 2, 2007 at 6:46 pm
DJ,
I have the exact same problem as you do, also with a presario 1800US. Have you found out anything since?
JC
Alex R said,
May 24, 2007 at 9:25 am
Hello. I have a similar problem (sorry, but I dont speak English). My laptop is a HP Pavilion and it have a charger of 18v, 3amp, the laptop would no longer run off external power, only with the battery works fine. And what i want to know is if I can replace the battery by a external source.
It does not matter to me if the functionality of portable is lost.
The battery works 10.8volt, 4 amp, but it has six (6) pins. Do I need to supply the 5 pins of 10.8v (4amp) each one? (One of them are ground, of course).
Or maybe is best to try to repair the power supply circuit (of the mainboard)?. REMEMBER: the ac adaptor is good!
Gracias
ALEX
Carl said,
June 11, 2007 at 5:48 am
I just replaced the jack in a Compaq 1210 that I picked up at a garage sale for $10.
When I first got the laptop, I was told the battery needed replacing. It did run internmittently on the power supply. and when the power supply was removed the battery would kick in for a short time.
The powersupply jack was broken. I took the whole laptop apart, I should have taken pictures, it was harder to put back together than I thought, I even have a few screws left over :D
I took the powerjack from an old PC speaker system. I checked the continuity of the jack to make sure the connections matched the original. I soldered pigtails, reassembled the laptop.
It now runs great on the powersupply. The battery is slow charging, not sure how long it should take but 8 hours later it is at 75%
However, when I disconnect the power cord, the battery does not take over.
I am not sure if I want to take the whole thing apart to investigate.
I suspect either a pigtail wire to the jack has come off or I have switched two leads on the jack, which would essentially create a short across the battery once the power jack is removed.
So I have removed the battery and I am using it as a not so portable laptop.
H Reich said,
June 20, 2007 at 10:49 am
I also have power jack failure on my HP laptop pavilion ze4125. I have taken it apart except for the motherboard which I am not able to get out. I have looked for hidden screws and even gotten it around the large ports that stick out. It feels like whatever is holding the motherboard is under that first big port. Can someone please tell me what to do. I have a new power jack but need to get to the back of the motherboard to clear the holes and resolder the pins.
neelakantan said,
July 12, 2007 at 1:57 am
i have compaq presario laptop 2111AP (actually it matches with the US model N1050v; the L-connector broke and HP suggested replacing the adapter! i made an improviso connector andworked fine; till last week that is!. it stopped responding (btw the battery alsogot exhausted) i thot the problem is with the connector as it was shaky; i soldered the pins firmly but it is of no use; i checked with my meter the continuity between the ground and the + terminal; every thing appears ok; then i accidentally tested with a normal tester the adapter output wires BOTH GLOW; when i checked the voltage ( thinking that may be the ground is having some negative voltage though somebody told me that the ground is 0V) it is showing -20v and the + is showing +27 v; isthe adapter faulty?
Ryan said,
July 17, 2007 at 11:05 am
Wow, my HP ze5000 laptop broke the same way and I fixed it last night referencing this article in about 3 hours! Not only is it fixed, but the new jack is heavy duty and will out last the laptop itself. The hardest part was getting the wires soldered correctly since I’ve never done it before. Of the three factory solders, only one was loose on the motherboard so I only soldered one wire from scratch (as opposed to three in the pic above) which saved me time. The new jack had metal leads long enough to reach the existing leads so I just sort of bent them together and used electrical tape to separate each lead. My local Radio Shack had the approprate DC jack and it looks better than the Philmore one since it’s chrome and the input is centered.
Go to Radio Shack and search for “Size N Coaxial DC Power Jack w/Switch”. Size N has a 5.5 OD and 2.5 ID. The ’switch’ verison is the one with the appropriate 3 leads and cost about $3.
Peter Prest said,
July 21, 2007 at 3:11 pm
I was able to download an excellent HP Pavillion zd7000 Maintenance and Service guide from the HP Pavillion sd7020US Notebook PC: Manuals site which made the dismantling very straightforward.
Peter Prest said,
July 22, 2007 at 11:24 am
A couple of further points on the service guide post I left yesterday.
If you need it Google HP Pavilion sd7020US Notebook PC: Manuals
I spelt Pavilion wrongly in the first post.
Section 5.11Top Cover has a couple of small errors:
In part 3. the last line should read:
2 PM2.5×5.0 screws
In part 6 there are two further PM2.5×8.0 screws near the hinges which need to be removed
For each section I put the screws in a separate glass jar with a paper slip listing the section. This greatly speeded up the re-assembly and avoided finding a screw left over at the end!!
Brian Smith said,
July 23, 2007 at 8:24 am
I have worked in the connector/cable industry for 30+ years. What HP has done with these is a very poor design and then specked in an inferior connector and jack. As many posts as I have read on this problem throughout the web, it sure seems to me that HP should recall these notebooks. I have an HP and a Compaq which are now down and out because of this problem. The Compaq is hell to get apart and I haven’t attempted yet with the HP.
Any thoughts on a consumer organization that should be contacted that could help generate a recall? HP should be helping it’s customers on this one.
Mark said,
August 9, 2007 at 11:20 am
I’ve got a Presario R3000 with the same problem. I know how to solder the jack back into place if I could only get at it! There is some sort of big metal plate covering nearly the entire motherboard (and the DC jack) that makes it impossible to even see the solders. I’ve removed every screw and its still attached to the motherboard somehow. Does anyone know how to get at the power jack to solder it?
thanks,
mark
stereotypebe1719@yahoo.com
Mark W said,
August 15, 2007 at 10:02 pm
I am yet another HP owner that owes Brooks a thank you. Not believing I had more than a 20% chance of correctly diagnosing and repairing the laptop, I nevertheless bought a low power soldering iron and a new power jack, dug up some old wire (no room on my HP ZE 4315 to install the case-mounted jack, so I opted for the pigtail approach), practiced removing resistors from an old modem, and followed directions. How shocked I was when I reassembled it and it powered up! Now I just need to learn how to reconfigure/reinstall stuff to get it to boot up. I also need to find a plug as shown on the delanoscientific.com website. So, a tip of the hat to Brooks and other posters that provided important tips. Here are a few I can pass on:
For those having trouble getting their laptop apart, try to find the service manual - it makes a huge difference! I started with one for a slightly different model, but more Googling led to the right one and it was a free download.
When other posters say it can be tricky to take the laptop apart, believe them. Actually, it will be even harder to reassemble it if you haven’t taken care to document your steps and keep all the screws organized. For each step, I placed a slip of paper showing the step number (from the service manual), and the number of screws associated with that step, on the computer near the screws, with a screwdriver pointing at one of the screws to be removed, and took digital photo. Then I taped the screws to a sheet of paper labeled with the step number and the corresponding service manual page number. This process was invaluable because it enabled me to avoid mixing or losing the screws and I was able to work backwards when reassembling. There were a couple of screws to be removed that the manual failed to mention (they were holding down the PCMIA card slot), but the manual was still extremely helpful.
Another tip provided by a poster was to “map” the pins on the old jack. I’m no electronics wizard, but I was able to do this with my cheapo 30 year old Radio Shack multi-tester. I first tested the plug from the power adapter and learned that the outside seems to be the ground and the inside is hot. Then I removed the power jack from the motherboard, attached it to the end of the adapter plug, and used the multi-tester to figure out which pins provided the same results as the bare adapter plug. Since there is only one way the jack can fit on the motherboard, this told me which motherboard terminals (holes?) corresponded to the power adapter ground and hot. Then I attached the new power jack to the power adapter and used the multi-tester to again determine ground and hot. Once the ground and hot were identified, the remaining pin had to be the switch. After that, it was simply a matter of soldering wires between the new jack pins and the motherboard terminals. Sounds complicated but, if I could do it, so can you.
While I had the motherboard out, I figured I might as well replace the BIOS battery (the computer is 4 years old). In the process of removing the battery, I broke one of the soldered connections between the motherboard and battery clip. As it turned out, it was not difficult to re-solder the connection - after all, I had practiced on that old modem circuit board just like Brooks advised!
Thanks again to all the posters that helped me salvage my laptop, and I hope my tips are helpful to someone else. The nice thing about having an old dead laptop is that there’s nothing to lose by trying to fix it!
- Mark
IanL said,
August 25, 2007 at 2:05 am
I am a sole trader operating in the UK as a PC Tech, but my background is in engineering, and I have been taking things to pieces for years. Over the last week, I have had to repair three laptops with damaged power connectors/power adaptors, but the last one is causing me a major headache. It is an HP Pavilion ZD8000. This particular model uses an oval connector, and the adaptor has certainly failed. The replacement adaptor from HP is relatively expensive (£100 +) so I thought I would use the cable/plug from the old adaptor and make a custom cable for use with a Trust 130W supply - all well and good except HP use a 3 wire arrangement (V_out, V_ret and ID) I can measure 19v on the mobo at the appropriate points, but the beast will still not power up - leading to two possible conclusions: 1) laptop is goosed and I have wasted a lot of time or 2) the ID line has some significance which I have not yet unearthed…
Anybody had any experience of this non-standard arrangement??
IanL
Jay said,
September 19, 2007 at 7:37 am
Hello everyone…I have a question..i have a persario laptop 3000z that started to have problem with it charging up…it couldn’t hold a proper charge….so i took it to a local repair center and they told me that the pin inside that is attached to the motherboard needs to be soldered again…..i went back next week and they showed me that they installed a new pin 2 times and it burnt through to the motherboard….i wanted to know if a such a thing can happen or is it their fault for burning the motherboard…thank you for your time and attention.
ernestom said,
October 8, 2007 at 12:07 pm
I have a similar problem with a Compaq Presario V3000Z. It’s still under warantee in the US, but I’m living in Argentina, so that won’t help.
Email with HP in the US suggested it might be the AC Adapter or the pins to the motherboard. Local HP, without opening my computer, claims my motherboard will need replaced, because they don’t do “repairs”. Another local repair shop tested my machine with their own AC Adapter and they claim it worked (I wasn’t present to witness this).
This might be true, since I’ve used the US power adapter in Brasil, Colombia and Argentina. Maybe I messed it up?
So I can buy a new AC Adapter (~$35) here in Argentina. But my problem seems to be similar to what’s described here and in http://www.delanoscientific.com/cpq1675.html.
I’m gonna purchase the extra power adapter. And we’ll see. Any advice would be welcome, as I’ve never touched a soldering iron in my life. :-(
Tom said,
November 1, 2007 at 4:43 pm
I have a HP XT412 that has a broken connection on the power jack. seems like an easy fix if i can get it open. is there an hidden set of screws? it seems to be held together in the center. any help would be great.
Dan said,
December 5, 2007 at 5:15 am
Thank you all for spending time asking the questions that I have already had. It has been extremely helpful. My question is this; could I simply solder the wires from the ac power cord directly to the motherboard? I know this would create a permanent plug, but the battery on my Compaq Presario 2100 is shot anyway so I have to always have it plugged in. I would like to know if there is even an easier way to fix the broken jack without having to purchase anything. My dog already chewed through the plug once, so I simply cut out the bad section and now have the mb exposed and the wires from the power cord. Is there a way to do this directly from here? I only removed the broken plastic housing from the old power jack. The three prongs are still in place. I just need to know if I can somehow hook them together and if so, which prongs I should use and how. Any help would be fantastic!!! Thanks
Randy said,
December 18, 2007 at 5:54 pm
I had the same old bs on my hp5400 series. I didn’t have the soldering ability so I took it apart and took it in to local shop. They robbed me of $39.95 for the jack and $40.00 labor for 5 mins work and the damn thing is already loose after 3 days.
There are screws under everything that you can get out. The cd drive, the small circuit board near the display, just everything that is screwed down has screws under it. And all of the outer ones on the bottom of course. And I think under the hard drive caddy. Bottom line, if you see a screw head, it probably has to come out. I guess I will have to do it again an learn to solder on circuit boards myself. No use taking it back to Trinity computers in cleveland, TN so they can do another bad slodering job.
Randy said,
December 18, 2007 at 5:57 pm
PS I also agree that HP or some one should step up and take care of this class problem with these laptops. And can you believe the guy said that is what hp charges them for the jack. No wonder, they are making a killing off selling replacement jacks for their own screwup.
Roan said,
January 17, 2008 at 12:57 pm
Hi,
I am presently repairing a Compaq Presario 2100 with power jack problem and a burned resistor (PR133). I already solved the power jack problem by resoldered it. I tested it with digital multimeter and seems fix the power jack problem. My main problem now is the small resistor was completely burned and also disconnected from the two black diodes (PD24
and PD25). Correct me if I’m wrong interpreting the values PD-for power diode and PR for power resistor (I only assumed that was definition based from my experience). First, I did the continuity testing from HOT (positive polarity) there was no connection after the end terminal of the burned PR133 resistor. So I assumed that the positive polarity stoped/disconnected because of the burned terminal. Second, I tested the GROUND (negative polarity to the rest of the mainboard and it had continuity.
Now my assumption is right that the PR133 caused the NO POWER to the whole system board. Here is my main problem, I don’t know the value of the PR133 resistor and couldn’t recognized it because it was complete burned. I don’t know if there is a generic substitution available in Radioshack. I don’t know how to get the value either.
Attached is the picture which I encircled the mentioned PR133 that was excerpt/taken from other person’s Compaq Presario 2100 motherboard I found from other website link.
I hope somebody can help me find the right value and where to secure one.
Thanks.
Compaq2100 user
Linda C. said,
January 22, 2008 at 9:03 am
I have a Compaq Presario R3000. It appears as if I have problems with the ac connector must have disconnected from the motherboard as well. Does anyone have a picture of how to disassemble the notebook so that we can get to the motherboard? I want to at least try to remount it prior to just throwing it in the trash and never buying an HP laptop again.
Nicolas P. said,
February 25, 2008 at 2:41 am
Reply to
#IanL said,
August 25, 2007 at 2:05 am
I am a sole trader operating in the UK as a PC Tech, but my background is in engineering, and I have been taking things to pieces for years. Over the last week, I have had to repair three laptops with damaged power connectors/power adaptors, but the last one is causing me a major headache. It is an HP Pavilion ZD8000. This particular model uses an oval connector, and the adaptor has certainly failed. The replacement adaptor from HP is relatively expensive (£100 +) so I thought I would use the cable/plug from the old adaptor and make a custom cable for use with a Trust 130W supply - all well and good except HP use a 3 wire arrangement (V_out, V_ret and ID) I can measure 19v on the mobo at the appropriate points, but the beast will still not power up - leading to two possible conclusions: 1) laptop is goosed and I have wasted a lot of time or 2) the ID line has some significance which I have not yet unearthed…
Anybody had any experience of this non-standard arrangement??
IanL
Have almost same problem.
Had the power supply (180W) burned out, made a temp fix that worked with an external conversion from oval to normal 2 pin connector by using the cable from faulty ps & gave it back to customer as a temp fix untill his replacement power supply come back.Brought it back after a couple days saying it never worked when he took it home.
Tried it again no power up.Replacement power supply (135W) came in , no joy still no power up.135w means 7.1A - 180w 9.5A at 19V.
The ZD8000 takes both according to HP