The last post in my series on retrocomputing covered the testing of my repaired CGA with the Micro 8088. The process of troubleshooting took several weeks, and it became apparent that a handy piece of hardware to have would be an ISA “POST Card“. This type of card is designed to display a series of diagnostic codes that are generated by the BIOS as it reaches certain milestones in its execution. This would have been very handy to have as a means of verifying if the Micro 8088 is functioning normally and executing BIOS code.

It is possible to buy an ISA POST card off eBay, but in the back of my mind I am wanting to learn how to use the KiCad software package to design and produce circuit boards. This may be the perfect excuse to design a POST card using KiCad, and do a whole lot of learning along the way.

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After repairing my CGA video card, and building Sergey’s Micro 8088 processor board and ISA 8-bit Backplane, I am now in a position where I should be able to test the combination of cards and verify if the CGA video output is working. I should also be able to find if the Micro 8088 is behaving correctly.

Join me after the break to read about the journey. Fair warning that this post is a long one. Hopefully you will find it interesting or at the very least entertaining to observe my failures and the strategies employed to work around them.

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In my last retrocomputing post, I tackled the problem of Repairing my CGA video card following quite a bit of foolish childhood damage.

In this post, I’ll document the fabrication of Sergey’s Micro 8088 processor board and ISA 8-bit Backplane. The hope is that I can get my CGA video card working with Sergey’s two boards, and combine them into a functional retrocompter. Continue reading →

Following on from My Introduction to Retrocomputing, I had found myself in possession of an IBM CGA card numbered “1501981APS”. At some point in my childhood, I had damaged the card by pulling traces off the PCB. I’m still annoyed at myself for that. Nonetheless, I still want to repair the card and attempt to get it working with Sergey’s Micro 8088. Continue reading →

A friend recently introduced me to the world of Retrocomputing. Specifically the work of Sergey Kiselev. Sergey has evidently dedicated many years to the creation of completely open-source designs paying homage to early computers such as the IBM PC-XT.

One such system is Sergey’s Micro 8088 processor board paired with Sergey’s ISA 8-bit backplane. A friend of mine was interested in building a system around both of these boards. Being an open-source design, the PCBs must be ordered by engaging with a PCB fabrication house. The minimum PCB order was in units of five, so I was offered one of each board to maybe build a retro system of my own. Of course I said yes. But what would I do with a system of my own? Continue reading →