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Micro Switch SW-11075

Posted: 25 Mar 2019, 02:01
by just_parker
Hey DT, I picked up an old micro switch (SW series?) board on ebay. So... I don't have any experience with reverse engineering or electronics repair; I've only built kits to date, but I'm excited to see what I can do with this board. I am hoping some of the OGs around here can give me some guidance on what my options are.
  1. This thing looks like it's been stored in a dirt pile since the 1970s. How likely is it that it can be restored to its original form?
  2. If the PCB is busted, how difficult would it be to harvest the switches and caps? It appears the switches are in good condition, just a little bit dirty. I can see that the metal clips, the PCB, and the sensors are all soldered together in a single assembly. I couldn't find anything on the goog about repurposing honeywell switches for a custom board. Is it even possible, or am I stuck with the existing layout? I bought it because it uses all 1u keys so I figured it would be easy to experiment with layouts.
  3. Will harvesting these parts for a custom design earn me the ire of the keyboard gods?
So, do any of you have any creative ideas for projects? PCB design is at the top of my list of things to learn, and I would love to convert this thing to USB in some form. Pictures:
signal-2019-03-23-223705.jpeg (213.74 KiB) Viewed 381 times
signal-2019-03-23-223707.jpeg (273.75 KiB) Viewed 381 times
signal-2019-03-23-223706.jpeg (290.83 KiB) Viewed 381 times

Re: Micro Switch SW-11075

Posted: 25 Mar 2019, 09:22
by Anakey
Hi and welcome to Dt The board looks to be in good condition i see no rust in the pictures that are provided. I would start by first removing the keycaps and then use denture cleaning tabs in warm water to clean them. For the switches themselves carefully remove them from the metal armature that holds them in place. Ideally for cleaning the switches they would be cleaned in an ultrasonic cleaner with Isopropyl alcohol (IPA) to remove dust etc that may have gotten into the switches. The armature and the pcb can also be cleaned with IPA. Conversion is something that I myself am trying to figure out on a board of my own though that uses the later SD series but the same methods might work with both switch types.

Re: Micro Switch SW-11075

Posted: 25 Mar 2019, 09:43
by PlacaFromHell
I don't have an SW keyboard but I'll try to help you as much as I can with my current information.
Those switches differ from normal open/close switches, instead they work with one pulse for close and other pulse for open. This is why they are not compatible with most potential controller replacements out there. Each switch has VCC/GND, the pulse output and a fourth pin, I don't remember if it works the same as the pulse output or if is anything else. Be aware you may need an external power supply to make it work.
In theory (nobody did that before, just heard about it), you could remove the rivets from the metal frame and put some bolts to attach the switches to another PCB.
I always wanted to have my own SW keyboard to play around, so envy :cry: