Fun With System Power Monitoring on the Apple IIe

Apple IIe with Power Monitor

One of my favorite vintage systems in the “Byte Cellar” is my 128k enhanced Apple IIe. It is also one of the most frequently used; I fire it up for IRC or BBS sessions several times a week, and game and watch demos on it almost as often. The Apple II (a //c, specifically) was one of my very first home computers, and I have owned several different IIs over the years. As such, the Apple II platform holds a special place in my heart.

As far as I am aware, this Apple IIe has the original power supply in place. (I acquired this unit on eBay in late 2008 [gallery] and got my first IIe back in 1986.) Not too long ago, I purchased a replacement power supply kit from ReactiveMicro, but haven’t had a need to install it as yet, but I’ve been a little curious how well the in-place PSU is supplying power.

A few days ago I was browsing eBay’s Vintage Computing listings when I saw a modern device that could quell that curiosity. The device in question is the “Apple II+ IIe & IIGS Continuous Power Monitor Display,” which is an external 3D-printed box housing blue and red LED readouts for the Apple II’s +5, +12, -5, and -12 power lines that is attached to a simple breakout card that can be seated in any slot in the system. The unit gives a constant reading of the bus voltage levels while, its creator assures me, drawing a negligible amount of power from the system.

As I said, I was curious about the levels being output by my aged PSU, but that’s not why I bought this thing. I grabbed it because it looks all retro-tech “blinkenlights” cool. It reminds me of something that might have been part of David Lightman’s IMSAI 8080 setup [info via Wayback Machine]. I had two free slots (5 and 6) and I now have but one.

Have a look at the box for yourself. The embedded photo is a still of the scenedemo F15 D’Gamma Clone released by C64CD in 2016 and the video shows the system running the demo Plasmagoria, released by French Touch (who make quite a few demos for the Apple II) in 2015. Audio is being output via a stereo, 8-channel (6 voices, 2 whitenoise channels) Mockingboard “K” soundcard slotted into the system and the secondary, HDMI display is being driven by a VidHD board. A few voltage fluctuations can be seen in the video but it doesn’t get much more exciting than that, I’m afraid. My need-case for the power monitor is a little silly, but it feels fun!

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One Response to Fun With System Power Monitoring on the Apple IIe

  1. George says:

    Hypnotic. Trying to keep any eye on the voltage readouts reminds me of one of those exercises in which one watches a basketball team pass balls around, and in doing so miss the guy in the gorilla suit walking through.

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