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There was a time when buying a computer also meant picking out a compatible terminal. There were many to choose from, some good and some bad. While we were partial to TeleVideo, other well-known names included Lear Siegler and ADDS. There was also Hazeltine, a well-known brand that could emulate many other terminals. [The Byte Attic] had an unusable Hazeltine 1420, and finally got around to getting it working again.
As you might expect, the old terminal was full of suspect capacitors. A power transistor was also missing, hinting that someone had been robbing this unit to fix another. In addition to fixing the device, the plan was to improve it with switching regulators. These old terminals generated a lot of heat with linear regulators.
The power supplies were often the major issue with these kinds of devices, and scorch marks under the bridge rectifiers didn’t bode well, either. Another concern: the chips that hold the character sets and some other logic are unobtainable. If they were dead, there would be virtually no way to replace them. The plan was to read them, if possible, and design replacements for the day they did fail. If it wasn’t already too late.
There are tons of pictures, and we appreciated that the post documents several early decisions that came back to bite them later. We know that feeling all too well. It is a long read with a happy ending. The ROMs did work, but because they are so prone to failure and so hard to replace, they went into storage and were replaced with an adapter using modern components.
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