Make your own ColecoVision at home, part 5
Leako – my ColecoVision clone – has reached a point where it has to become a thing that is actually buildable by other, more normal, people. On top of that, we’ve got chip and part shortages out the wazoo, and a smattering of bugs and reliability issues to knock down. Will revision number seven be the charm?
This revision of the board was mostly to try and improve reliability of the machine. While heavily testing (playing with) my previous-generation board, a lot of things bugged me.
For starters, I didn’t like that Leako version 6 relied on a barrel jack to provide the regulated +5VDC power to run the rest of the system. Not only do you have to worry about the quality of the regulation, and find a compatible adapter, but I also added some (still untested) protection circuitry to avoid reverse-polarity episodes. If there’s one thing I’ve learned from reading console-repair articles, it’s that the average person does not understand DC barrel jack polarity.
I had a couple options, such as designing a polarity-independent input circuit, going up to a 9VDC input and adding a 7805, or finding another way to power it altogether.
In the end, I ended up going with USB, as I had on my Sega SG-1000 clone, the Soggy-1000 .
Getting a USB “B” jack is fairly inexpensive, it has okay strain relief, and everyone has a couple USB power adapters lying around. Of course, it’s not a panacea: some USB power adapters are a ripple-fest with terrible regulation, because USB was never really intended to be a universal power supply. Some chargers will push around 5.25V or even higher, which might damage some of the salvaged ICs. I ended up using a nice (but $18) Anker wall-wart to test my system with, and I was fairly happy with the results.