How to mod beamspring connectors for tightness


12 Sep 2020, 21:56

The blue modern 3.96mm card edge connectors that are often found on ebay/aliexpress, and are used for converting Beamspring keyboards are often a lot looser when compared to the original connector.
They are often so loose that some columns/rows don't make proper contact, and even vibrations can knock a row/column always-pressed/always-unpressed.

If you already have a converter built and soldered, then your best option to mitigate this is to add a piece of paper, to increase tightness. Keep in mind that if looking at the keyboard and connector as if you were typing on it, column contacts are on the bottom left, and row contacts are on top right. So I recommend adding a piece of paper on the top-left, where there are no contacts that are really in use. If the tightness problem is really severe, you may experiment with increasing paper thickness, or using multiple sheets of paper, and you can also try adding a piece of paper on the bottom-right, underneath the rows. (Original idea by kmnov2017).

This guide is a much better solution, but it only applies to you if you still have a pristine unsoldered connector, that you can mod to be tighter. If you follow these steps, the connector will be around as tight as the original connectors, and you will need to use more force to connect/disconnect the converter to/from the sense pcb.

Step 1 - remove the pins

Remove the pins, by grabbing the part that is solderable, and pushing them straight through with pliers.
The pins are very easy to bend, so be very careful.
Try to grab a good surface area when pushing, and always push in the direction that is perfectly parallel with the pin metal.
01_push_pins_through.jpg (712.78 KiB) Viewed 207 times
If something like the following picture happens, it's best not to attempt fixing this pin by bending it back. just break it off, and using a needle push it so the other end falls out of the connector. This is a good reason why to get pins that are bigger then 2x30 pins, because you have extra pins in case you break some. (Also right now 2x30 pin variants don't seem to be available anyway)

(If you don't have any extra pins, then really-really pay attention to make sure something like this doesn't happen, and I guess if it does, try to save it, but set it aside, and only use it for contacts that don't carry any signals.)
02_if_something_like_this_happens_do_not_try_to_save_the_pin.jpg (1.09 MiB) Viewed 207 times
I recommend pushing out all pins at once, rather then modding pin-by-pin. This allows you to be faster. So after you pushed out all pins, you have an empty plastic connector, and a pile of pins:
03_until_you_get_a_pile_of_pins.jpg (1015.75 KiB) Viewed 207 times
Step 2 - First Bend

This is what a single pin looks like:
04_this_is_what_a single_pin_looks_like.jpg
04_this_is_what_a single_pin_looks_like.jpg (236.99 KiB) Viewed 207 times
Bend the contact part of the pin upwards by 15-20 degrees: (does not have to be very perfect)
05_bend_the_contact up_around_15_20_degrees.jpg
05_bend_the_contact up_around_15_20_degrees.jpg (781.82 KiB) Viewed 207 times
Because of the little guide-holes in the connector plastic this bend is not sufficient. The little guide holes would bend the pin back into its original shape, if you inserted it like this into the connector:
06_the_first_bend_is_not_enough_because_the_little_holes_in_the_plastic_force_the_pin_back_in_its_original_shape.jpg (1.08 MiB) Viewed 207 times
Step 3 - Second Bend

So you need to add another bend in the middle of the contact part of the pin. Try to make it so the two marked blue lines are roughly parallel. But again perfection is not necessary: Angles are not so important to be perfect, but try to make so that the position of the second bend is consistent across pins, for aesthetics. This will still work even if the position of the second bend is inconsistent.
07_add_another_bend_in_the_middle_of_the_contact.jpg (921.84 KiB) Viewed 207 times
To make the second bend, I held the pins with tweezers, and I applied pushing force where shown by red arrows:
08_how_to_add_bend_with_tweezers.jpg (559.07 KiB) Viewed 207 times
After I took the picture I realized that I have stronger tweezers the tips of which are made out of ceramic, so I did all the remaining pins with the ceramic tweezers. My needle nose pliers were too thick for this, but if you have very thin needle nose pliers, I recommend using those instead.
09_i_used_ceramic_tweezers.jpg (354.92 KiB) Viewed 207 times
Step 4 - Gently push the pins partway back

Push the pins back into the connector until part of the pin goes through the hole on the back of the connector.
Do not apply force on the contact side of the pin to make the pin snap back into place.
This step only places the pin back halfway:
10_gently_push_the_pins_back_in_place.jpg (817.16 KiB) Viewed 207 times
Step 5 - Pull the pins from the other side, with pliers, until they click
11_pull_the_pins_until_they_click.jpg (896.62 KiB) Viewed 207 times
Step 6 - Solder the connector to your controller

Do not try to put the connector on the beamspring after modding the connector without having it soldered to a controller.
The modded connectors are much-much tighter, and require force both to put the connector on, and take it off.
You risk bending the pins, and also you risk some of the pins popping off while you take it out.
Soldering it increases its mechanical stability. Solder it first, and only then try it!

Here you can see a non-modded connector on the left, and a modded connector on the right.
You can see how much gap there is between the pins on the unmodded connector:
12_comparing_modded_and_nonmodded.jpg (353.15 KiB) Viewed 207 times
Here you can see the side view of the pin shape after modding:
13_modded_pins_in_connector_side_view.jpg (190.66 KiB) Viewed 207 times
I was very disappointed with the reliability of the non-modded connectors, but I have done this mod on 9 connectors so far, with 100% success, and they are 100% reliable now!
Last edited by pandrew on 12 Sep 2020, 22:29, edited 8 times in total.


12 Sep 2020, 21:57

Great job Andrei, I am going to do that on my beamspring

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12 Sep 2020, 22:02


I think this is a good idea. Very often the connectors you get are very loose. Not sure why it is, but they often fall off. This is a quick easy way to fix. Good job thanks.

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