Category Archives: RetroChallenge

Added double-sided support to Quay 900 floppy formatter

I’ve added support for formatting double-sided eight-inch floppy disks to the Quay 900 floppy formatter program I wrote as part of my RetroChallenge 2014/07 project. The source code is still provided under the GPL v3.0 license. I still haven’t worked … Continue reading

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RetroChallenge project completion

I assembled and debugged one channel of my vector generator, and wrote some of the firmware to drive it. I have unfortunately NOT finished building the second channel, though I got <fingersĀ separation=”10mm”>this</fingers> close. Would you believeĀ <fingersĀ separation=”20mm”>this</fingers> close? I’m going to … Continue reading

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Vector generator success!

After correcting a few wiring errors, the single-channel vector generator works, though it needs some calibration. I have the vector generator on my test bench with the Silicon Labs EFM32WG starter kit (ARM Cortex-M4F microcontroller) running the firmware, and a … Continue reading

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One-channel vector generator proto passes smoke test

Bench power supply reports 3.3V@3mA, +12V@18mA, -12V@53mA. Found and fixed a wiring error. With DAC output near 0V, output of first opamp, unipolar to bipolar shifter, is -1.0V, as intended. Next step: hook up SPI to microcontroller. I’ll be using … Continue reading

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One channel of vector generator wired on breadboard

I’ve wired one of the vector generator channels on a breadboard, and took two photos. It’s ready for testing, but at the moment I can’t find enough test leads to wire up the breadboard to my three-output bench power supply … Continue reading

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New vector generator design

Since my HP 1350A and 1351A vector generators are not working, and I don’t have time to fix them for RetroChallenge, I’m building a simple vector generator from scratch. The design is a slightly updated version of Steve Ciarcia’s design … Continue reading

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HP 1338A Lissajou curve test

I hooked up two analog signal generators to the XY inputs of the HP 1338A Tri-Color XY display to display a Lissajou curve as a test of the inputs, and posted a video.

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HP 1338A manual testing video

I’ve checked the basic functionality of the HP 1338A Tri-Color XY display using only its front panel controls, and posted a video.

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HP 9830A memory upgrade

I have an HP 9830A desktop computer, circa 1972, which runs BASIC using a custom bit-serial processor built out of TTL, with an architecture similar to the HP 2116 minicomputer. I’m planning to use the 9830A in my RetroChallenge entry, … Continue reading

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RC2015/07 entry – vector display system

For RC2015/07, I’m going to hook up an old vector display (the retro part) to a modern microcontroller and either write a new game for it or port an old one. Vector displays were used on computers from the 1950s … Continue reading

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