I am looking for a socket which is able to receive the connector of the ThinkPad X41's keyboard ribbon cable. How do I identify the socket so that I can find it on the (German) market?

Background: I want to build a custom keyboard controller, to connect the keyboard via USB.

Annotated photos Picture: Receptacle (left, 20 pins) and plug (22 pins)

  • \$\begingroup\$ You can buy this as a product: amazon.com/ThinkPad-USB-Keyboard-with-TrackPoint/dp/B002ONCC6G \$\endgroup\$
    – markrages
    Apr 2, 2013 at 13:28
  • \$\begingroup\$ @markrages Thanks, but none of those keyboards is interesting for me because they are too wide. Also, I would like to add some custom electronics for configuring the TrackPoint without the need for a driver. \$\endgroup\$
    – feklee
    Apr 2, 2013 at 13:34
  • \$\begingroup\$ Too wide? That looks to be the same width as the X60 I'm typing on. \$\endgroup\$
    – markrages
    Apr 2, 2013 at 15:19
  • \$\begingroup\$ @markrages The keyboard you mentioned looks very similar to a T4xx keyboard, and certainly it is much wider than an X41 keyboard (total width: 26cm). For the intended purpose, i.e. desktop usage, it wouldn't make much sense to use a non full size keyboard. My use case is different. \$\endgroup\$
    – feklee
    Apr 2, 2013 at 15:27
  • \$\begingroup\$ I posted a picture of the official ThinkPad USB PCB here: superuser.com/a/1548142/122042 \$\endgroup\$
    – pkamb
    May 3, 2020 at 7:40

5 Answers 5


I've dug up the schematics of the T60 keyboard as well as the X41. There is a very high chance that the keyboard receptacle is AA01B-S040VA1 manufactured by JAE. The landing pattern is the same and it looks very much the same (Google images for the 30 pins version: AA01B-S030VA1)

Molex SlimStack 54363-0478 can be used as a substitute to the AA01B-S040VA1. My previous edits say otherwise because of my bad soldering. After fixing the soldering, it works well.

  • \$\begingroup\$ It's promising that they still used that receptacle in the T6x, which are not as ancient as the X4x. \$\endgroup\$
    – feklee
    Jun 12, 2013 at 20:28
  • 1
    \$\begingroup\$ I find the TE Connectivity's 4-5353512-0 (Data sheet: docs-asia.electrocomponents.com/webdocs/0db1/…) to be a promising candidate. Despite having different male plug, the receptacle looks a lot like what Thinkpads use. Only 2 things need to be checked, first is whether the width at the edges of the keyboard's plug matches the datasheet and if the metal contacts of the keyboard can fit onto the TE's receptacle. I haven't been able to check myself because I don't have a calliper. IBM may use combination of connectors to prevent copying maybe. \$\endgroup\$
    – congIA
    Jun 13, 2013 at 17:36
  • \$\begingroup\$ This all makes a lot of sense. So I mark this answer as accepted, at least until it is ever proven wrong. \$\endgroup\$
    – feklee
    Jun 17, 2013 at 14:03
  • 1
    \$\begingroup\$ The AA01B-S040VA1 fits! \$\endgroup\$
    – feklee
    Oct 14, 2013 at 13:58

When dealing with unknown connectors, please follow these steps to aid your search:

  1. Measure the "pitch" or distance between connector pins
  2. Count the number of connector pins
  3. Count the number or rows of pins
  4. Measure the pin length/depth
  5. Determine the gender of the connector (male/female... should be obvious ;-) )
  6. Measure the overall dimensions (that's the dimension of the smallest box that can contain the entire thing)
  7. Determine what type of connector it is by function (see next list)
  8. Finally, look for clues for the manufacturer (brand, logo, letter/part number marks, etc.)

Here are the usual types of connectors by functions (lifted from TE's Connector Picture Search which is highly recommended):

  • PCB connectors
  • I/O connectors
  • Power connectors
  • Terminal blocks/strips
  • Terminals/splices
  • RF or Coax connectors
  • Ribbon or Flat Flex Wire
  • Fiber optics
  • Sockets (chip, processor, memory)

Now based on the eighth steps, here's what I can figure out from the information you had provided so far:

  1. -- no guess --
  2. 40 pins
  3. 2 rows (2 x 20 pins)
  4. -- no guess --
  5. you have both the male and female samples
  6. -- no guess --
  7. board-to-board stacked
  8. related to the ThinkPad series of docking stations

Your laptop's datasheet, aka service manual, was released in 2005 so that makes the probable manufacturing year(s) to be around a year or two before that. The connector therefore must have existed in the market during those times +/- 3 years prior or after; somewhere between 2000-2008. Some hints I found (Google) pointed me to this connector datasheet by Japan Aviation Electronics (JAE) which was released (or updated) in 2007 and matches currently known specs of your connector. Please verify further if it indeed is the connector you are seeking by measuring the missing dimensions and comparing it against the datasheet.


From the new dimension data you have provided, the connectors you're looking for is still manufactured by JAE with part numbers AA01A-S040VA1 for the female/socket and AA01A-P040VA1 for the male/plug. Check out the datasheet here.

  • \$\begingroup\$ Thanks a lot for the suggestions! Just some notes: 1. The connector is inside of the laptop, i.e. not related to a docking station (position 8). 2. The connector by JAE looks quite different, especially the cable attached to it (keyboard has ribbon cable). \$\endgroup\$
    – feklee
    Apr 2, 2013 at 18:22
  • \$\begingroup\$ Just added dimensions. That gives: 1. 0.5mm, 4. 1.5mm, 6. 15mm × 6mm (socket) \$\endgroup\$
    – feklee
    Apr 2, 2013 at 18:49
  • \$\begingroup\$ The JAE socket is definitely not it. The difference is symmetry of pins: In the ThinkPad plug, the pins in the two rows are mirrored. In the JAE plug, the pins are arranged in a zigzag pattern. \$\endgroup\$
    – feklee
    Apr 2, 2013 at 19:09
  • 1
    \$\begingroup\$ I had edited my answer as I was able to match your dimension data with another JAE connector. \$\endgroup\$
    – shimofuri
    Apr 2, 2013 at 20:33
  • 1
    \$\begingroup\$ You know, you could try contacting JAE with the pictures/info and they might be able to help you @feklee \$\endgroup\$
    – Passerby
    Apr 2, 2013 at 23:42

I would say sift through a component distributor's website, such as Farnell

Then go about sorting one option at a time.

Connectors > Board-to-board/Wire-to-board/stacking (stacking would be my first choice) > then start selecting various parameters, such as 40 pins, 2 rows, 1.27mm pitch (I'd measure this if possible, but it's fairly standard and looks about right).

Hopefully there won't be too many components found, around 100 or so (4 pages).

If you still can't find it, then try a different branch higher up the tree, such as board-to-board connector, or even ffc/fpc based on your second picture.

Sorry I don't know outright, and good luck!

  • \$\begingroup\$ Thanks for the suggestions! I already found some candidates. Pitch (distance between centers of pins) is 0.5mm, by the way - this socket is small. \$\endgroup\$
    – feklee
    Apr 2, 2013 at 13:55
  • \$\begingroup\$ The only problem is that all of the sockets I found are SMDs, but there seem to be solutions, e.g. the SOIC to DIP Adapter. \$\endgroup\$
    – feklee
    Apr 2, 2013 at 14:34
  • \$\begingroup\$ Is there a reason you don't want surface mount? I don't mean to sound condescending, but if you can't solder SMD components, invest in a decent iron with a needle tip (I use a Weller 0.2mm) or a butane gas iron with solder paste. It really is worth it in the long run! \$\endgroup\$
    – raaymaan
    Apr 2, 2013 at 16:37
  • \$\begingroup\$ I first want to experiment with a breadboard. There is going to be quite some reverse engineering, since I don't know the pin out. \$\endgroup\$
    – feklee
    Apr 2, 2013 at 17:00

Use a better magnifying system and look for something that might be a partial model or series number or manufacturer's logo or abbreviation. If you can't see it on the exposed laptop part, look on the mating part instead, they'll both indicate the common series of parts you need to look for. If you still can't see it, desolder one or both connectors and check the bottom. Usually there is some kind of marking on such connectors.

  • \$\begingroup\$ Actually, that was my plan for today. :-) Also I've ordered a second used and broken X41 off eBay. Off of that I can just desolder both components, for usage and for inspection. \$\endgroup\$
    – feklee
    Apr 3, 2013 at 8:48
  • \$\begingroup\$ I now used a microscope to look at the connectors. The only thing printed (embossed) on the outside was a "B" on the plug. Of course it could be that on the backside of the components or on the board itself there is more information. But that requires desoldering, which I may do once I receive the other X41. \$\endgroup\$
    – feklee
    Apr 3, 2013 at 10:45
  • \$\begingroup\$ I finally desoldered (actually destroying the component): There is no manufacturer or model information visible, neither on the board, nor on the backside of the component. \$\endgroup\$
    – feklee
    Jul 27, 2013 at 19:52

I was unable to find a supplier for the part in the accepted answer, but I did find another part that can be modified slightly to fit: Molex SlimStack 54363-0489 (distributors).

The dimension D in the datasheet is 0.5 mm too long on the 54363-0489, but can easily be trimmed down with a scalpel. (Actually, it was only 0.15 mm too long for my keyboard connector, but that's within tolerances.)

Molex SlimStack 54363-0489 drawing Molex SlimStack 54363-0489 dimensions

  • \$\begingroup\$ Thanks! At least on Taobao, it's fairly easy to get the original part. If you have a link to your keyboard project, please consider adding it here. \$\endgroup\$
    – feklee
    Mar 19, 2021 at 5:38

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.