After years of lurking it's time for me to give something to the instructables community. I hope this can help!
By the way,
I WILL NOT TAKE ANY RESPONSABILITY for accidents or injuries occured trying or as a result of this instructables! DO IT AT YOUR OWN RISK!
and, if you want to give a try,
BE CAREFUL! Use glasses, gloves, mask and everything you need for YOUR SAFETY!
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The power adapter of my HP dv6 notebook died a month ago.
Using a multitester I noticed that there was zero volt output. also putting my ear near the box I could ear a strange noise, some kind of syncopated twittering!
So I went to my computer shop and bought a new adapter, a universal one, but I wasn't completely satisfied with this solution:
- the new one has shorter cable, annoying!
- it doesn't connect very well, sometime I have to move the jack in and out until the notebook see it again;
- the new adapter has only 2 pins output while the HP one has 3 pins.. that third pin must be useful someway!
Enough! I've decided to open the black box to see If I can fix it!
Step 1: Tools
What I've used (and what maybe you need):
- Scissors
- Japanese sharp blade (x-acto knife should work well too)
- pliers
- tweezers
- tin wire
- insulating tape
- duct tape
- multitester
- soldering iron
- desoldering pump
- dremel with cutting tip
- Scissors
- Japanese sharp blade (x-acto knife should work well too)
- pliers
- tweezers
- tin wire
- insulating tape
- duct tape
- multitester
- soldering iron
- desoldering pump
- dremel with cutting tip
Step 2: Opening the adapter
The adapter did'nt work anymore. strange noise. using the multitester I noticed that the ground and Volt pin where short-circuited!
I supposed the problem should be in the cable. Time to open the black box!
Memo: Before going any further, unplug everything!
The box is made of two plastic shells fused together, there are no screws or clips, the only way to open it is cutting the junction line. Using dremel with cutting tip it take just 5 minutes. Luckly the inner circuit is protected by a metallic shell, so don't be too worried to cut something inside, just take your time and be very careful near the input and output cable.
When you can see metal on all the sides, gently open the plastic shell. there is some glue to keep all together, but it will surrender soon.
I supposed the problem should be in the cable. Time to open the black box!
Memo: Before going any further, unplug everything!
The box is made of two plastic shells fused together, there are no screws or clips, the only way to open it is cutting the junction line. Using dremel with cutting tip it take just 5 minutes. Luckly the inner circuit is protected by a metallic shell, so don't be too worried to cut something inside, just take your time and be very careful near the input and output cable.
When you can see metal on all the sides, gently open the plastic shell. there is some glue to keep all together, but it will surrender soon.
Step 3: Unsoldering the cable
Before desoldering take note of how cable are connected to the pcb.
In my adapter there are 3 pins: GND (ground), ID (identification?) and VOUT (voltage output).
My output cable is coaxial and it is connected this way:
outer layer go to GND,
mid layer go to VOUT,
inner layer to ID.
TRIVIAL NOTE: Seems like the ID pin is used for some kind of communication between adapter and notebook.. It transmit a signal at lower tension so that notebook recognize the adapter as an original HP product!
Unsolder the cable one pin at a time, from outer to inner, using the unsoldering pump and helping yourself with tweezers.
If the industrial soldering doesn't want to melt use this trick: melt some of your toxic and full-of-lead soldering wire on it and heat with your soldering iron. This will mix the two kind of tin lowering the melting temperature.
Control with the multitester if the VOUT and GND pins are still short-circuited. I hope the answer is no :)
OPTIONAL PART:
Maybe now you want to check if the adapter works well before proceding..
This method is dangerous so please skip this part if you don't feel like doing it and be very careful!
Put the metal box back in one of the plastic shell's halves in a way that it is insulated from your desk and everything else. Choose the best side to face you considering that you want to easily reach the pins with the INSULATED tips of your multitester. Without touching any part of the open adapter plug the input cable. All you have to do is touch VOUT and GND pin with multitester tips to check if there is a correct potential difference (of 19 Volt for mine adapter). Checked? Unplug!
In my adapter there are 3 pins: GND (ground), ID (identification?) and VOUT (voltage output).
My output cable is coaxial and it is connected this way:
outer layer go to GND,
mid layer go to VOUT,
inner layer to ID.
TRIVIAL NOTE: Seems like the ID pin is used for some kind of communication between adapter and notebook.. It transmit a signal at lower tension so that notebook recognize the adapter as an original HP product!
Unsolder the cable one pin at a time, from outer to inner, using the unsoldering pump and helping yourself with tweezers.
If the industrial soldering doesn't want to melt use this trick: melt some of your toxic and full-of-lead soldering wire on it and heat with your soldering iron. This will mix the two kind of tin lowering the melting temperature.
Control with the multitester if the VOUT and GND pins are still short-circuited. I hope the answer is no :)
OPTIONAL PART:
Maybe now you want to check if the adapter works well before proceding..
This method is dangerous so please skip this part if you don't feel like doing it and be very careful!
Put the metal box back in one of the plastic shell's halves in a way that it is insulated from your desk and everything else. Choose the best side to face you considering that you want to easily reach the pins with the INSULATED tips of your multitester. Without touching any part of the open adapter plug the input cable. All you have to do is touch VOUT and GND pin with multitester tips to check if there is a correct potential difference (of 19 Volt for mine adapter). Checked? Unplug!
Step 4: Reparing the cable
So you know there is a short-circuit somewhere in the cable.. but where?
The best way to proceed is to cut away the last part near the black box, right after that kind of black plastic spring that should help to preserve the cable from broking (..and always fail!).
If the problem is in the cable, you can be sure it's somewhere in that critical zone. Check with multitester if now is ok, or cut another few centimeters and test again.
Don't throw away the plastic spring! Try to remove the broken cable from inside the spring and to put back it around the remaining good cable. I've had to cut the spring in three part cause it was soldered to the cable, yet it has been still useful.
Once the spring is back around the cable, strip the wire one layer at time. Looking at pictures you can see that I cut the wire on the long way cause I reuse the plastic coating for insulation and strenght.
Twist together the wires of each layer and insulate with tape. Check to which pin each wire must go. Try to rearrange the three wires so that it'll be easy to solder back it on the adapter, then block everythig with tape.
Resolder the wires to the adapter, from inner to outer pin.
The best way to proceed is to cut away the last part near the black box, right after that kind of black plastic spring that should help to preserve the cable from broking (..and always fail!).
If the problem is in the cable, you can be sure it's somewhere in that critical zone. Check with multitester if now is ok, or cut another few centimeters and test again.
Don't throw away the plastic spring! Try to remove the broken cable from inside the spring and to put back it around the remaining good cable. I've had to cut the spring in three part cause it was soldered to the cable, yet it has been still useful.
Once the spring is back around the cable, strip the wire one layer at time. Looking at pictures you can see that I cut the wire on the long way cause I reuse the plastic coating for insulation and strenght.
Twist together the wires of each layer and insulate with tape. Check to which pin each wire must go. Try to rearrange the three wires so that it'll be easy to solder back it on the adapter, then block everythig with tape.
Resolder the wires to the adapter, from inner to outer pin.
Step 5: Closing the box
Put back together the plastic shell and block it with duct tape. Be careful to not leave exposed any metal part.
You're done! Plug everything.. and cross your fingers.
You're done! Plug everything.. and cross your fingers.
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Cheers!
I never glued mine shut either since it seemed to me that it was the twisted shielding/groundwire that caused the break in the first place. Also that third pin gave me grief, it seems HP no longer makes adapters like that. I wonder why XP
http://www.instructables.com/id/A-Hot-Knife-cuts-plastic-rope-opens-welded-pla/
but like all things involving melting plastic. do it with plenty of ventilation
Obviously you never use the knife for food again, as it may have burned on plastic.
And then put some cyanoacrylate glue (the real name of superglue) along the inner part of the seam and put a weight or a C clamp to hold it closed while drying, you get it to look as good as new!
Even if you need to open it later, the glued power supply will crack open again with the same method.
I've done it on 2 different DV6000 chargers I repaired already with a short circuited cable on the strain relief.
It seems the strain relief is not very good, or people pull the cable to much.
I'm looking at this instructable and wondering why go to the effort of using a saw. I've opened and repaired the cords on about 6 adapters using just a hammer to open the case. All you do is give some sharp hits to the corners with the supply on a solid surface. the glue all breaks and it comes apart.
I like the idea of the knife though and will definitely try this next time.
Nowadays with a camera on (almost) every phone, it is really easy to snap a photo of the wires/connectors/layout before you start taking something apart.
I (almost!) always do this before dissembling a piece of unfamiliar kit.
Note: Using a vice is best bet to crack open the battery charger case as using a knife runs the risk of cutting an internal part such as the transformer or a capacitor.
Keep up the good work!
- If you suspect the cable, get some needle (piercing) probes for the multimeter and you can check continuity, although when you measured a short that isn't the likely problem - the short is more likely a burst capacitor - but I have not read far enough in the instructable to know, this is just a guess.
- Instead of opening the case with a dremel tool, try putting it in a vice and applying pressure to bulge and pop the seams. Sometimes this will work, other times not, but if it works then your seams still have a lip for a better reassembly and sturdier glued together joint. Otherwise I hold them together with nylon wire ties.
- On your wire the third "ID" pin is probably Current Detect, the I being the electronic symbol for current. It does not transmit a signal to recognize the adapter as an original HP product or anything like that, it allows the notebook to detect when current lowers and the charging cycle is near completion. Some notebooks have this built in instead.
- Lastly, most of the time a failed adapter has a failed capacitor or transistor in it. Some of the time the cable is broken, but it is rare to have the problem seen here with a shorted cable. Good job tracking down the problem but I wanted people to be aware that it usually takes more work than this to fix one. Also, ebay is a good source for replacement OEM power adapters cheap, people end up parting out dead notebooks and have the power adapter left over to sell.
I'll take the opportunity to diddo the "I WILL NOT TAKE ANY RESPONSABILITY for accidents or injuries..." disclaimer at the top of this tutorial. Throwing electrical devices in the freezer...probably not the best idea, but I got reports done.
tape some stiff paper(business card works great) around the inside of the case allowing about 1/4 inch above the edge before closing the 2 halves together.
this make a dam to keep the sealant out of the electronics.
seal around the gap with epoxy then dress up the gap when the epoxy starts to get tacky.
When done you won't see that the unit was ever opened. Just looks great this way.
Problem is, when duct tape is heated the adhesive becomes gooey and can leech out making a mess and being vinyl, heat and UV (sunlight) can make it brittle and crack.
Certainly adhesive is a good choice, but consider using adhesive that actually melts (dissolves) the plastic so it rejoins. For example PVC cement instead of silicone or RTV etc. It is also better than superglue. Test what you plan to use on an inner area of the case, let it sit for half a minute on the plastic then scratch the area with a toothpick. If the plastic has softened from the adhesive you know it is dissolving it and will be a good adhesive to use.
PS - if you really think your adapter is getting too hot, drill a few tiny vent holes in it, but be sure they aren't big enough or a a child isn't going to be near it so there isn't a risk of something being stuck in the holes - same situation as with a wall AC outlet, you have to assess risk then decide what to do.
IIRC the ID pin is used to tell the charger circuit if is safe (meaning you bought a brand name power supply) to charge the battery, as well as to communicate the power rating in Watts of the power supply.
A lower power rating on the supply indication is needed if the machine can not run a full power for the given supply and has to run at reduced speed. (take a machine shipped with a 90W/115W supply and plug a compatible brand name 65W supply into it).
The ID seems to usually be one of the 1-wire EEPROM ICs from Maxim/Dallas Semi or similar vendors.
I once had a HP car charger that I modified to power a Dell laptop, but not charge the battery since it didn't have an ID pin connected to an eeprom with the right data in it.
I've had nothing but laptops since the '90's. Several different brands, and ALL the power adaptors were (1) designed to break early and often, (2) expensive to replace, with a markup comparable to movie-theater popcorn, (3) unique - or so they said - to each and every model, (4) only available through the mail, forcing "road warrior" users on deadlines to carry a heavy, clunky, bulky backup everywhere just-in-case.
My (at least theoretical) approach was to shore up those P.O.S. strain-reliefs, with duct tape if that was all I had, as soon as I got the darn thing out of the box. I never had time to make it look pretty - when I remembered to do it, which sometimes I didn't.
Good to see various folks working on contingency plans!
v v
First, this side, { [====] }-then this side..
^ ^
the seal should break, unless they went to extravagant measures to seal it.. This way, a few drops of crazy glue, and you can re-seal it..
I repaired an old Dell supply like this, and was able to re-seal it with little noticeable damage.
A lot of wall-wart transformers crack open the same way.