Powering Lenovo Thinkpad With Dell Power Supply
Intro: Powering Lenovo Thinkpad With Dell Power Supply
When coming home from a job at a customers site at weekend, I realized that I forgot to take the power adapter of my Thinkpad W510 with me.
I had to finish the work and needed some power source. Luckily I had a Dell power supply, but unfortuantely the dc jacks where different.
Having a look at the power supplies I found out that they are very close in specification.
Lenovo (DCWP CM-2 135W);
- 20V DC
- 135W
Dell (DA130PE1-00);
- 19.5V DC
- 130W
I thought that the 0.5V and the 5W difference of the power supplies should not be a problem ... but the dimension of the power jacks where. The Dell jack did not fit into the Lenovo socket.
While you work on such power supplies, even if this is low voltage dc, there is high current. Shortening the dc jack may lead to demage of the power supply and can even cause fire because of generating heat. Be careful, double check every step. Be as much precise as possible.
I had to finish the work and needed some power source. Luckily I had a Dell power supply, but unfortuantely the dc jacks where different.
Having a look at the power supplies I found out that they are very close in specification.
Lenovo (DCWP CM-2 135W);
- 20V DC
- 135W
Dell (DA130PE1-00);
- 19.5V DC
- 130W
I thought that the 0.5V and the 5W difference of the power supplies should not be a problem ... but the dimension of the power jacks where. The Dell jack did not fit into the Lenovo socket.
While you work on such power supplies, even if this is low voltage dc, there is high current. Shortening the dc jack may lead to demage of the power supply and can even cause fire because of generating heat. Be careful, double check every step. Be as much precise as possible.
STEP 1: Comparing the Power Supplies
Some basic for beginners about dc power supplies can be found here;
http://www.appropedia.org/Low_voltage_connection_basics
The voltage is nearly the same. Also the power that both power supplies are able to spend is nearly the same. Polarity of the pins is also the same.
When looking for the connector type of both power supplies I was not able to find a standard describing them. It seems to me that Dell and Lenovo are using their own connector design.
http://www.appropedia.org/Low_voltage_connection_basics
The voltage is nearly the same. Also the power that both power supplies are able to spend is nearly the same. Polarity of the pins is also the same.
When looking for the connector type of both power supplies I was not able to find a standard describing them. It seems to me that Dell and Lenovo are using their own connector design.
STEP 2: Connector Construction
Both connectors are built the same way. They are using a techniqe that can handle relatively high dc voltage and current at the same time. If you look for standard dc connecors you may find a wide range that are covered by standards
http://en.wikipedia.org/wiki/Coaxial_power_connector . The standard mentioned here does not support the high current and the relatively high dc voltage that Lenovo uses (see also http://en.wikipedia.org/wiki/EIAJ_connector ).
The plug is built by two metal tubes that are separated by insulation matterial. The pipes offer big surface to conduct. There is a small pin in the center of the jack. I think that this pin has no meaning for the electrical functinality of the connection. I think it is just a guiding pin with no electrical connection.
The socket is mainly built out of plastics, to support the jack. Inside the socket there are small clips that conduct to the tubes when the jack is plugged in. There are two clips for each tube to offer the best conduction possible. One pair of clips conduct to the inner tube the other pair to the outer tube.
http://en.wikipedia.org/wiki/Coaxial_power_connector . The standard mentioned here does not support the high current and the relatively high dc voltage that Lenovo uses (see also http://en.wikipedia.org/wiki/EIAJ_connector ).
The plug is built by two metal tubes that are separated by insulation matterial. The pipes offer big surface to conduct. There is a small pin in the center of the jack. I think that this pin has no meaning for the electrical functinality of the connection. I think it is just a guiding pin with no electrical connection.
The socket is mainly built out of plastics, to support the jack. Inside the socket there are small clips that conduct to the tubes when the jack is plugged in. There are two clips for each tube to offer the best conduction possible. One pair of clips conduct to the inner tube the other pair to the outer tube.
STEP 3: Modifying the Dell Power Supplies Jack
The idea is to widen the jack of the Dell power supply a little to make it fit into the socket of the Lenovo notebook.
I made small slit into the jack's tubes. This way they became somehow flexible like a strong spring.
To cut the slit I used a Dremel tool. The slit need to be cut all the way down the tubing. It need to end some millimeters inside the base of the jack. Be careful not to cut the guiding pin.
After cutting the slit needs to be cleaned somehow. Some chips may be left from the cutting. They should be removed with sanding paper. I used type 180 and type 240 paper.
Check the slit carefully for any defects and chips after sanding it.
I made small slit into the jack's tubes. This way they became somehow flexible like a strong spring.
To cut the slit I used a Dremel tool. The slit need to be cut all the way down the tubing. It need to end some millimeters inside the base of the jack. Be careful not to cut the guiding pin.
After cutting the slit needs to be cleaned somehow. Some chips may be left from the cutting. They should be removed with sanding paper. I used type 180 and type 240 paper.
Check the slit carefully for any defects and chips after sanding it.
STEP 4: Usage
Be careful when pushing the modified plug into the notebook. Looking at the construction of the socket, it will be best to keep the slit in a diagonal way. Do not place vertical or horizontal. By using it diagonal all clips inside the socket are able to connect to the tubes.
Do not twist the jack while plugging it in or when it is plugged. The slit inside the tubes may scrape of some plastic of the socket of the notebook.
The modified jack is still useable in Dell notebooks too.
I used the Dell power supply for a whole working day to finish my work without problems. I am using it from time to time at a customer site, leaving it there and using my original power supply at home.
You should always be aware of the fact that you are dealing with high current here. Leaving chips inside the jack may lead to short circuit and may destroy the power supply. The current may be able to burn of chips but may cause fire by doing so. If you notice a strong smell or unusal heat on the connector turn it off immediately.
Do not twist the jack while plugging it in or when it is plugged. The slit inside the tubes may scrape of some plastic of the socket of the notebook.
The modified jack is still useable in Dell notebooks too.
I used the Dell power supply for a whole working day to finish my work without problems. I am using it from time to time at a customer site, leaving it there and using my original power supply at home.
You should always be aware of the fact that you are dealing with high current here. Leaving chips inside the jack may lead to short circuit and may destroy the power supply. The current may be able to burn of chips but may cause fire by doing so. If you notice a strong smell or unusal heat on the connector turn it off immediately.
6 Comments
MarcM6 5 months ago
For newer thinkpads, this won't work. The insist on 20V or a bit over, they do check the center pin resistor to see the power supply claims to be the right amount of watts, and even if you put the right resistor, it will then try to pull 5 to 10A on my P70 or P73, and if the voltage drops, it will ignore the power supply too. See this for details
https://marc.merlins.org/perso/linux/post_2020-05-...
I did make my own power supplies for thinkpad using lipo batteries to extend runtime, it was possible but not trivial (hence the page above).
JimmyG70 5 years ago
I tried this and it will only give a trickle charge on the Lenovo W520 with 2 hard drives, it will not charge whilst in use so i am assuming it is the second drive or something that requires the extra power, i tried reducing the processor performance and also sent the nvidia graphics to not engage on any applications but it also did not work. It will charge the laptop overnight whilst not in use only.....any suggestions would be welcome
thank you for the excellent idea it almost worked for the W520
MarcM6 5 months ago
So this trick as described here, will only work with old thinkpads.
For recent thinkpads, even another thinkpad power supply will not work unless you put the right resistor on the center pin. See
https://marc.merlins.org/perso/linux/post_2020-05-04_Hacking-Power-Supplies-and-Battery-Pack-To-Get-Around-ThinkPad-P73-Broken-Power-Supply-Design.html
D.V 8 years ago
Thanks for the write-up. Was searching the web to confirm that this exact Dell 130 watt power supply that I have a couple of, had compatible specs internally to be used with a Lenovo W510 machine. which I only have 90 watts for (usable, but won't support full potential of the processor).
I am not handy with a dremel, so will I probably plan to splice the cables on a Dell 130, anb a Lenovo 90 watt.....and solder on proper connectors and heatshrink so I can simply swap leads to the power supply. So I can use a dell end, or a lenovo end. on both supplies.
ramialmo 10 years ago
How about the other way around? I have 2 Lenovo chargers I want to use for a Dell computer
Monty^ 11 years ago
I just happen to have a spare DELL adapter, and a Lenovo tablet PC that needed a second adapter for the docking station - this little mod was just the ticket.
The only departure I made was to cut two slots 180 degrees apart, and even then it was a extremely tight fit but that's actually desirable in my case using it for the docking station - it'll rarely be removed.
Thanks for the inspiration. I would have never thought of doing this otherwise.
By the way, I believe the centre pin is for charge signaling and acts as more than a guide pin.