Sharing my PC-MX2 & Restoration BLOG

    Zitat von fritzeflink

    I think you should 1st make an image of the hd and please don't use it until that.


    I can lend you my spare MFM Reader/Emulator. The BBB is the one with only 2GB of emmc but for testing it is enough.

    I'll write a short howto for you to read and then emulate the hd until you have your own hardware.

    Yeah, I didn't plan on doing anything besides browse the hard disk, but I won't be able to use if at the moment anyways. I think it was a fluke, random chance. My PCB's I had made for the MFM Emulator (the same one you are using), should come tomorrow. And then I will be building it soon, so I don't think I need yours. The only thing is that I only purchased the parts listed on the Mouser BOM, which didn't include a few things like the extra memory chip, and cables. I'm hoping that it isn't necessary for what I need to do, based on what I'm reading on the site.

    It's been a lot of work, but I have some big updates.


    Shortly after my last post, I ordered five (minimum order) MFM Emulator PCBs to be made for me by JLCPCB in China. They did a great job, and they look awesome. I spent a little extra money to get them in black with an ENIG coating, and gold-plated contacts on the fingers. Along with 45 degree bevel on the fingers to slide in a little bit easier. The ENIG coating is to avoid oxidation and improve the solderability of copper contacts and plated through-holes.


    ,


    I've got three left, that I would offer first the readers of my thread ;)

    Only asking cost and shipping (5.60+2.80 = 8.40€)


    I tested it hooked up to my lab power supply before connecting it up to anything really important, and setup the beagle bone to work headlessly. I tested it using a disk image and cables fritzeflink sent me, Thanks Fritz! And everything worked first try. Next up was the part that I was dreading the most. Trying to recover the data of the old hard drive.


    It took 12 attempts, and trying different settings from conflicting sources on the internet of what the correct settings for the hard drive were. But what turned out to be the most important changes were not relying on the analysis of the program entirely and manually setting the number of cylinders, along with changing the number and thickness of shims that were inserted, and power cycling. While the beginning tracks could always be read for me. The slightest misalignment kept the cylinders at the end from reading properly. Eventually I ended up with it going through the whole read process without any retries or cylinder misalignments. At that point, I made sure to not touch it and power it off until I got a couple reads.



    I changed all the cables and setup for emulation, and it worked! There were only some files in the root directory that have weird names, but that could be from the previous user. Everything else works, even the COBOL projects were there from the company that owned the machine. I only explored it a little bit, but one of them was a program for entering patient information. I may try some more reads in the future, to see if those filenames can get cleared up. But I think this is as good as it is going to get.


    I was able to find an exact replacement battery for the MX2, it turns out to be a 3.6V AA size lithium battery with axial wire mount. Along with some Wago terminals that will allow me to easily replace it in the future.

    Lithium Battery Saft LS14500CNA with Axial Wire Mount: Amazon.de: Electronics & Photo

    WAGO 221-2411 Terminal 2 Conductor 4 mm² Through Connector with Lever (Pack of 10) : Amazon.de: DIY & Tools


    I have a sheet of carbon fiber I got for free from my local hacker space that I'm going to use to mill a backplate for the emulator. The reason I need this is because the MFM isn't the correct size. I had thought about using KiCad to redesign the emulator so that it would fit in the mounting posts of the hard drive after I remove it. But I thought it was a little much for a first project with KiCad, someday in the future I might. This backplate will slide into the currently unused card cage in the center of the MX2, mounting it securely on standoffs so it's not floating around in the case.


    Today I've modeled the MFM emulator in Fusion 360 to design a backplate, and I'm hoping to use the space's Shaper Origin to cut it out. If you haven't seen it before you should watch some YouTube videos. It really awesome.