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Surface Dock teardown (brick-shaped dock for SP3/SP4/SurfaceBook)

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Comments (43)
  1. Eric says:

    Great teardown. I really appreciated your write up on the earlier SP3 Dock.

    Can I ask, can you tell if the inclusion of the PCIe switch mean the Surface Connector port supports PCIe?

  2. Danchar4 says:

    Eric, thanks for the kind words. I'm not sure why the PCIe switch chip is there. I suspect its not being used for PCIe at all when docked to the SP3/SP4/SurfaceBook and is simply a switch or pass-through signal re-gen for DisplayPort. These chips can be used for either application. I'd have to dig into the spec sheets to understand why this chip needs to be used alongside the STMicro DP1.2a splitter chip.

    Because the SurfaceConnect cable is modular, I suspect this dock may be future-proofed and able to be used with different types of connection protocols by swapping the cable and applying a firmware update to program the pins. That's how I would design it anyway…

    Its pretty clear now that the 40-pin connectors on the SP3/SP4/SurfaceBook are NOT using PCIe at this time and just pass USB3/DisplayPort/Power.

  3. NickW says:

    I can't believe this.  For days I have been searching for this exactly info that you've posted here.  I plan to built my own Surface Pro 4 ultra-portable multi-monitor setup with a full HD 15.6" usb powered monitor as main.  The goal is to stay under 5 lbs and everything can be battery powered up to 8 hours.  The information you've provided here would make it all possible now.  I can DIY my own docking station without the weights and integrate it into an external battery bank to make it all one unit.  Thank you and thank you.

  4. NickW says:

    Could you confirm that without the wall outlet, will the surface pro 4 internal battery feed power to the dock through the magnetic connector ?   Will the ports on the docking station work this way?

  5. Danchar4 says:

    NickW, sounds like a great project!

    The dock is not designed to be powered by the Surface Pro/Surface Book. Its the other way around. You need 15V DC to power the dock circuit board which then feeds 12V to the Surface.

    Be warned that the barrel connector on the circuit board of the dock looks like a non-standard size.

    When selecting your battery pack and hookups, you probably don't need to spec for 15V @ 6 amps – that spec is for the Surface Book with discrete GPU and is pretty generous. If you're using a Surface Pro 4 you can probably do fine speccing for 3 amps. But if you want to build it rock solid to work with the Surface Book, then overspec it just like MS did – its only like one wire gauge difference so may as well go with the thicker wires.

    Please post pics of your build when you get a chance!

  6. Firmware updates says:

    Since the 206-02-17 collection of surface pro 4 updates we have had problems with the external monitors sometime not working. The best fix at least for a few machines has been to power off the dock fo 30 seconds and then plug it back in, this is after reboots of the surface itself have made no difference.

    Is there enough in the dock to warrant this? could the firmware updates cause an issue with the dock?

  7. Olive says:

    Thanks for the great work. Only one issue that all your pictures show in page at their 100% size so only a small portion is actually visible in the page. I tried Edge, IE11, Chrome, all the same result.
    And a question about the magnetic. What is it for?

    1. Danchar4 says:

      @Olive, thanks for the tip. Looks like the media settings got lost in the new MSDN theme layout. Pics are now updated.

      As for the magnet, It looks like it is there to simply align the proprietary cable to the board. I expect future models will not have the cable glued in and will let you swap the cable out for different connections.

  8. Jordan says:

    I found out something interesting recently. I have a spare dock, but no power supply. I bought a 15V power supply and had a connector that matched the dock and soldered it up +15 to tip and ground to sleeve. The dock wouldn’t come up. So I checked the connector and realized that the inner sleeve and outer sleeve were not bonded. Checking my working dock, the sleeves are ground and +15V, while and the pin is 3.3(ish)V. I’ve looked everywhere on the OEM power supply for an indication that the PS is supplying 3.3V, but there is no mention anywhere. I presume it’s to power the PI3PCIE3442ZHE, but for the life of me I can’t figure out why they step down from 15V to 12V and 5V (for SP4 and USB, respectively) on the board, but chose to do 3.3V off the power supply.

    1. David Smoot says:

      Might be a 1-wire protocol like the Dell Laptop power supplies. Newer Dell laptops only charge if they can make a 1-Wire connection with the power supply and get the expected read from a 1-Wire EEPROM in the charger. Bet you lunch that is what is going on. Buy a 1-Wire reader and see if a 1-wire discovery works on that pin.

    2. Pawel says:

      Hello when you connected the power supply without signal on the tip did it work?

    3. mn says:

      Is there any other adapter that works with this dock. Microsoft ones are quite expensive! You can find universal ones but I am not sure if they work!
      Man they suck! Why can’t they reuse the same interface so you can use your original adapter from surface?!

      1. Danchar4 says:

        MN, how much were you quoted for a replacement docking station power supply and from whom? I haven’t seen them listed for sale anywhere. I always thought that if you called MS product support and explained that you lost your power supply for the docking station that they would ship you a new one for ~$30.00 USD. At least that was the case for the older Microsoft docking stations. Have you given that a try?

        BTW the docking station power supply was redesigned to provide a lot more power for the Surface Book devices as well as two DisplayPort interfaces and four USB3. The older design would not provide enough power.

        1. mn says:

          I’m in Germany and here it is so difficult to find something like this. The cheapest that I found were around 50 Euro while you can find the original surface pro 4 adapter for around 10 Euro (I am not sure which model though)! Usually adapters are cheap but this one is not and I am not sure if other ones work on this or not; probably not as I read in the comments.
          I never thought about contacting them though!

  9. David Smoot says:

    Are the weights riveted? I travel a lot and the weight is a liability not a benefit. I am thinking about just removing the weights.


    1. Danchar4 says:

      I guess you could call them plastic rivets. I think the way its put together is the metal weight is placed on the chassis then a tool that looks like a soldering iron comes down and melts a bit of plastic to hold it in place. Looks like there are 8 spots like this per weight. I bet you could drill them out. I don’t know if there is also adhesive on the other side of the weight. It wouldn’t surprise me if there were.

  10. Let me see if I understand it, Could I remove the weight, without any consequences??? This weight isn’t used to cooling or to dissipate hot…

    1. Danchar4 says:

      That’s right the weights are not used as heat sinks so it will be OK to remove them if you can do so without trashing the plastic casing.

      1. I’ll try it… and if I can do it I’ll share pictures about the process…

        1. Hi everybody… I did it!, I remove the weight from my Surface Dock, and it is more portable now :0) . If someone want to do it let me give us a little advice, you just need to drill the holes (just a little), until the “burr” has gone. and with a screwdriver pry to separate the weight from the plastic case, be carefull becouse it has glue between the weight and the plastic case. In the bigest weight, I use a flat pliers to pull out the weight. Good Luck.

          1. Danchar4 says:

            Very cool Toño!

            Hope you don’t mind, but I’ve linked your image in the main posting and given you the credit.

        2. Joel says:

          Tono, I am curious
          How heavy (grams or ounces) are the weights?
          How heavy is your dock now that the weights have been removed?

          1. Exactly in grams or pounds I don’t know becouse I don’t have a Weighing machine nearly, but the weigh lost was substantial…. more portable, less heavy… :0D

  11. carl says:

    Is there a way to extend the magnetic ended cable? I wanted to hide the dock in a cupboard but this cable is very short. cheers

    1. Danchar4 says:

      Hi Carl,

      The connectors are Microsoft proprietary so it would be difficult to make your own extension. Also extending the cable too far will reduce the signal strength and might cause issues. I think you’re stuck with the short cable.

      1. carl says:

        Makes sense thanks, will have to work on slimming down the brick instead. cheers

  12. Someone think in build a case that include both, the energy charger and the circuit board to do it more “portable”??? Maybe build this by a 3D printer…

  13. jbc22 says:

    Hi Danchar.
    Thanks for the great teardown! Do you have any idea of the pin connections in the SurfaceConnect connector?
    Is usb 2.0 routed in the connector as well as usb 3.0, or is the differential pairs from usb 3.0 somehow used when connecting a usb 2.0?

    1. Danchar4 says:

      For the connector pinout please see the comments from Mikhael in this thread:

      Yes both USB 2.0 and 3.0 are passed though.

  14. Erwin says:

    Hi everyone, I got a surface dock from ebay months ago and I tested it and it was working nice but now after using it one night it does not work anymore :/ there is 15v coming from the supply so I am thinking is something inside. By looking the teardown I dont see a lot of fixable component. Any hint of what can this be? Could this be something with the firmware? It does not power the usb port either

    1. Danchar4 says:

      @Erwin, I always suspect power supply issues first. Even though your P/S provides 15v, that may change under load. Its also possible the center pin on the P/S is not providing the “power good” signal to let things boot up. Try opening up the box and testing what voltages are present across the test points on the board when your tablet and USB ports are plugged in.

      If you haven’t already, try registering your device at and making a warranty claim. If you only bought it months ago and it is a new device, not refurbished, then you should be covered under warranty. Just provide your email receipt to MS.

  15. William says:

    A little late to the post but I was looking to take apart my surface dock and try to add a switch to turn on and off the charging ability of it. I would like to keep the use of all of the extra ports but not have it constantly charging the battery. I currently have an external monitor, keyboard, and mouse, and a few other things with my surface book (w/ gpu) when I am home and hate to have to not use it because of the charging. I assume that there are multiple wires inside of the Surface Connect Cable, is there any way you could find out which one would be the power supply to the battery? Or if this is even possible? Thanks

    1. Danchar4 says:

      Hi William,

      The pinout is documented in the comments here:

      May I ask Why are you trying to disable charging?

      I’ve heard folks claim that keeping devices plugged into the charger reduces long-term battery life, but with zero data to back up that claim on modern premium devices like Surface. I do know that Microsoft invested a lot to get the charging cycles optimized for long-term battery life to help sell into Enterprise. Nobody wants to have to swap out units in Enterprise settings after 2 years just for batteries unlike a lot of low-end laptops. The charge cycles are typically optimized to reduce thermal strain on the Li-ion cells and not charge/discharge unnecessarily.

      Having a dock plugged in and using the device draining the Surface battery all the way down, and then charging later is very unlikely to extend the long-term battery life on these devices. I would advise against this approach and use the devices as the super smart engineers designed them.

      If there is some other reason for disabling charging like reducing digital noise for audio or something like that, then I’m all ears to understand your scenario!

      1. William says:

        The reason I want to disable the charging of the dock is to prevent overcharging and damage the battery. Yes I understand that there should be tech that keeps this from harming the batteries, being a mechanical engineer myself. However I am skeptical of leaving this plugged in all the time, I have seen way to many batteries cooked from overcharging. I have talked with Microsoft about leaving the book plugged into the charger and they warned me that leaving it plugged in for long periods of time would damage the life of the battery. Being as expensive as it is I do not want to take that chance. I love the dock it is very convienient for using a full desktop setup but I would love to disable the charging on it. Thank you for getting back to me, I will check out that other post and see if I can figure out how it relates to this surface dock. Thanks.

        1. Danchar4 says:

          Hi William, interesting that MS gave this advice. Was that from Customer support? I think in general most electronics companies say you shouldn’t leave stuff plugged in and not in use while on holiday and such, but nobody heeds that advice 🙂

          If you’re serious about this, I suspect simply taping over the outermost 3 pins on each side of the of the docking connector will accomplish what you want. 12 pins total. You’ll have to use very thin tape like Kapton so you don’t gum up the receptacle on the tablet. I would advise against nail polish as it will wear off and gum up the receptacle – although you could probably clean it out with alcohol or acetone. I remember using the nail polish approach as a reversible way to disable the problematic daytime-running lights on my Volkswagen – worked like a champ but the connection pins were much larger and easier to work with.

          In the lab we disassembled the connectors and were able to connect USB hubs and such without using the charging, but there were some gotchas IIRC. If you run into issues, post up again and I’ll see if I can dig up my notes.

          1. William says:

            Yea I had asked multiple tech support people from Microsoft about this and they all said it will damage the battery, Does it actually? who knows… but i’d rather not take the risk plus the battery lasts forever so its not a big inconvenience to leave it on battery power. But my plan was to cut open the insulation on the cable and find whatever wire was the hot lead for the charging and put a switch on it so I could turn on and off the charging ability easily without unplugging it. Hopefully this will not affect any of the other functions of the dock. worse case scenario I will just reattach the wire and it will be as it is now. Thanks for all the information. I’ll be sure to comment back if it works.

          2. Danchar4 says:

            Another thought for you. You might be able to build a little extension cable out of Molex nanopitch parts and insert your switch that way. Then you don’t need to destroy the MS-provided cable.

        2. Josh says:

          I am trying to do the same thing. Of all the manufacturers I have tested, ONLY Lenovo preserve their battery charge cycles on their X1 premium model. It only charges the battery when it’s down to 20% and stops at 80%, the optimal conditions for Lithium prismatic batteries used in slim laptops and tablets. It also has a nice feature where the USB port remains powered even when the laptop is off to allow charging your phone. The Surface Pro 4 has none of this. It discharges the battery below 2% and charges to 100%, and battery life indeed drops off even with one overnighter on the dock. My SP used to last me all day, but after only one week on the dock it’s down to 2 hours. So MS engineers are smart, but not that smart. The closest documented understanding they come to even understanding the issue is talking about battery saver to reduce power consumption, which is not what we are talking about. I was going to put in an inline SPST switch into the wire but if you have done this successfully please do share.

          1. William says:

            So, I was able to cut into the cable and find the wire that delivered power to the battery. I was able to cut it and put a spst switch in. All of this was possible, too bad it wont function when you do that. It seems that for the surface to recognize that it is hooked up to the dock, it must be charging. So when the dock is plugged into the surface with the switch off all of the usb and display ports stop working, but when you turn the switch back on, everything begins to function normally, but unfortunately it also charges. I did however purchase the Microsoft mini display port to Hdmi adapter. And I was able to shave away some of the insulation on the plug to allow the dock to be plugged in at the same time as the display. So Currently when using my external monitor I leave the display cable plugged into the surface book and then just use the dock as a fancy way to charge it every once in a while when needed. At this point I am probably going to look into getting a more permanent desktop setup and use the surface book for portable applications. As a side comment to your “Microsoft’s engineers are not that smart,” they are just the opposite. They are so smart that they tell you how to ruin their product that only they can fix… Sucks that this is the mindset of their engineers but this is how they make money. Can’t knock their product though, the Surface Book is no joke when it comes to portable power. Have had no problem running many 3D cad software and other graphic intensive engineering software. Sorry I couldn’t help. Please let me know if you think of another solution.

  16. MuTe says:

    Any idea where I would be able to buy a Surfaceconnect cable? Got a Surface dockingstation where the cable has been cut in half.
    I’ve managed to disassemble the dockingstation, and the Surfaceconnect cable is now unplugged.

    1. Danchar4 says:

      I don’t think replacement cables are available for purchase. Your best bet is to call Microsoft product support for this one to see if they would offer a discounted exchange or see if a used or broken unit comes up on eBay.

      If you have the MS complete extended warranty they may cover it under the no-questions-asked swaparoo policy.

  17. James says:

    Has anyone found an extender for the power supply?

    I’m looking to extend the barrel connecter that plugs into the dock. So the power supply brick can stay on the floor and the dock up on a standup desk. Really just looking for something that has a female connector on 1 end and a male connector on the other end so that the actual dock can be further away from the power.

    1. Danchar4 says:

      Hi, when I looked into this last year, I couldn’t find an off-the-shelf barrel connector with the same measurements as the MS one. Its probably a part from Lite-On or Fox-Conn, but I couldn’t figure it out. I know its not exactly what you want, but rather than extending that end of the power supply, you can just as easily get an off-the-shelf IEC7 mains power cord. More details here:

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