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

[I’m a Surface Fanatic. I *love* all the Surface devices, accessories, and the rich ecosystem built around this brand. I also love tearing devices apart. So in the spirit of my last teardown series lets do a teardown of the new brick-shaped Surface Dock.]



Opening your Surface Dock will likely void your warranty. You should take every precaution when tearing apart any consumer electronic device. Even though the Surface Dock operates at 15V, you should be careful to keep metal bits and tools away to not short out anything. If you are not familiar with the safety aspects of working with electronic projects, do not attempt this teardown. Ifixit has a good safety guide for electronic teardowns and repairs.

Part 1 – pull the plug

This is probably the toughest part of the teardown. Surface marketing material notes that the Surface Dock includes a “SurfaceConnect” cable. At first glance it looks like the cable is removable, but tug on it lightly and it doesn’t budge. This is because it is glued in. You need to tug on it really hard to free it. I recommend gripping the strain relief with pliers thicker than what I’m using and prying against the case to get a little leverage. Be careful. Its possible to destroy the end of the cable if you crimp the wires or pull the insulation off.

Here is the connector on the dock side of the SurfaceConnect cable which looks like Molex nanopitch. Note the kapton tape around the housing which snugs the connector into the dock. The glob of glue chipped off, but you can see the residue partially covering the laser-etched text “IAJRADG” on the housing which I presume is a combination of manufacturer and manufacturing date codes.


Part 2 – remove bottom cover

Now that the cable is free, its time to open up the mystery brick. Just like the last generation clamp dock, you need to pull off the bottom cover. This time instead of a plastic sheet with sticky residue, its a rubber sheet with sticky residue. Pull the sheet off to reveal the adhesive:

Poke 4 holes in the corners to reveal four T6 torx screws. Loosen the screws – they should stay put with all the adhesive around the holes:

Gently shake the dock and lift off the bottom cover. You may need to use the flathead screwdriver to pry it free. Flip it over to reveal one of the weights:


Part 3 – remove the circuit board

Use the T6 torx screwdriver to remove the 4 screws holding in the circuit board and the 2 screws holding the SurfaceConnect receptacle shell:

The circuit board is now held in with a little friction at the USB ports but is mostly being held in place at the audio port which protrudes through the chassis and the SurfaceConnect receptacle shell. Gently pry the board on the corner opposite the audio port and the SurfaceConnect receptacle to tilt it and pull it out. It may help to bend the long edges of the plastic chassis slightly to give a little extra clearance for the audio port. If it doesn’t come out easily, don’t force it – you can bend the board and ruin it.

You’ll notice the shell around the main SurfaceConnect receptacle has a magnet on it with a red dot and the whole assembly falls right off:

Here is a close-up of the connector shell:

More weight on the other side:



Part 4 – Examining the circuit board

You can gently pry off the integrated circuit shields with a 1/8″ slot screwdriver to reveal the interesting chips.

Under the top shield:

Under the bottom shields:


The circuit board part number is “PCB X898350-001”. It is very densely populated compared to the older docking station. The board appears to be 6 or 8 layer and has a gazillion 8-pin ICs everywhere. I suspect these are VRMs and power switches. I didn’t take the time to look to closely at them. Let me know if you have any questions and I’ll try to answer.


Part 5 – Power delivery analysis – only 60 watts delivered to SB2?

The molex connector soldered to the board appears to be part number 171982-0142. There are 42 pins plus a shell that acts as ground. Each pin can withstand up to 500mA current. In the Microsoft implementation, 8 pins are used for +15V for a maximum of 4 amps or 60 watts power delivery. In order to deliver ~90 watts, an additional 4 power pins are needed (5 to deliver up to 105 watts) but there are no pins left since the rest are used for DP and USB. Molex only specifies a 42-pin or an 80-pin connector. The 80-pin connector appears to be too large to fit in the MS dock form factor which is probably why MS went with the 42-pin model.

The wires in the Lorom cable assembly are 32 gauge which are only capable of ~530mA. On the Microsoft connector side there are 4 power pins – each capable of ~1.6 amps. Two wires are attached to each pin and run to the Molex side.


Thanks to my colleague Jon for providing the Dock and doing most of the initial teardown.



Update: Tono has shared a photo with the weights removed. All you need to do is drill the 8 little plastic “rivets”.


Back to the main blog


48 thoughts on “Surface Dock teardown (brick-shaped dock for SP3/SP4/SurfaceBook)

  1. 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.


  2. 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?


  3. 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!


  4. 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.


  5. 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?


  6. 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. 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?


    • @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.


      • Hi! The blog is amazing! One huge question… Do you think it’s possible to buy the cable with the magnetic connection. Mine isn’t working but I don’t want to buy everything again just because one cable has issues… thank you so much.


  8. 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.


    • 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.


    • 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?!


      • 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.


        • 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. 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.



    • 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…


    • 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.


  11. 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…


  12. 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?


  13. 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


    • @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.


  14. 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


    • 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!


      • 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.


        • 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.


          • 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.


  15. 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.


    • 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.


  16. 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.


  17. Just found something awesome in the PCIe specifications. Take a look at that connector on the board. Its looks like an OCulink connector. That may answer the question of what interface Microsoft is using for Surface connect. That would be pretty sweet.


  18. Hi Dan, do you know if the mDP and USB connector on the Suface still work if a Surface Dock is plugged in? Or are they just re-routed to the dock instead?
    Really nice teardown btw, very informative!


  19. I know this is an old post, but has anyone opened up the magnetic cable/connector? I have a surface book that cannot power dual 4K displays as the dock connector is too close to the displayport. I am wondering if I can shave the end down to allow access to the mini dp opening.


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