Gregory's Serverthis RAM chip has a little attitude! actually it was working just fine. the bad chip was a different one. i replaced it and the machine booted!
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44 comments
 it was easy to remove, but i couldn't find out what kind it is. nothing at the local hardware store matched. spoiler: it is something special. after a ton of research, it turns out to be a Medeco Biaxial lock (original) but with a rare 3-pin arrangement. since the front face does not have a logo, this is likely a special version made just for IBM. https://www.lockwiki.com/index.php/Medeco_Biaxial  @tubetime Even with tumbler disassembly, I'm so surprised you got it to work. I also wonder if it's cheaper to have a locksmith make a key from that or try to use it for a mold. @tubetime I guess you could get a metal key cut from it at the local hardware. @tubetime your Medeco Biaxial key reverse engineering feels like something @deviantollam would be interested in. He might also be able to suggest where you could get a suitable metal blank to suit your pinning (or to suit a repinned version). (3D printed sintered metal probably also isn’t strong enough for frequent use, but a metal key cast from the negative of your reverse engineered key model might be sufficient for light use.) @ewenmcneill @deviantollam i found his video on the pinning tray, so that was helpful. @deviantollam @ewenmcneill thanks for the kind words. right now it is just some random notes and a crappy solidworks file. i am not convinced i have the depths right. i also have another lock (with no key) of very similar make, so i'll probably take that one apart and compare the pinning @tubetime Wow. This is genius. Amazing work. Thanks for sharing.  @tubetime Pretty impressive reverse engineering there. Impressive! First idea would be James from Clough42 on YouTube. He seems really skilled with 3D CAE and delicate CNC machining.  @tubetime you’ve already got a working model for an FDM printer, so I’m wondering if this would also work in a SLS metal printer? No idea what the cost of the print would be though. Or you could have a go at making a high temperature silicone mould of the key and casting it in pewter.  @tubetime neat! Could you get an outfit to print you a copy in metal with DMLS? I have no idea how much such a thing would cost @tubetime Nice work! Now that you have the shape, it could be possible to cast it in bronze :)
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@HoustonDog if you don't have a compatible keyboard but the port itself works, maybe build an Arduino-based converter from PS2. if the port is dead, well, fix it already 😉
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@tubetime Oooh interesting. My 25 doesn't have this lock. Mine was a single floppy model, and the right bay is just 100% blank. @tubetime Seems like a majority of the PS/2 Model 25 I find for sale are the 8086 monochrome variant. Kinda want to get one of the 286 color variant sometime—just like the ones my middle school had—although it’s a low priority. (Apparently there was a 386 variant too but I expect it to be hard to find.) |
even though it has a hard drive, it's not the 286 version of the Model 25 (the only versions to come with a stock hard drive). in fact it has been upgraded with the famous NEC V30! an 8087 has also been installed. someone tricked out this machine.