What I Learned from Repairing Old Gear

· 2 min read

It took me two attempts to see the pattern. Below are a few notes, roughly in the order I worked out them. None of this is new, and that is partly why it works. Some of this will be plain; some of it took me years.

The middle part

The board worked on the second revision, after one very plain fix. A multimeter answers most questions before an oscilloscope is needed. Every winter I revisit the same questions about enclosures. This got going as a quick note and slowly turned into something longer.

Most of what I know about e-paper displays came from getting it wrong first. What surprised me most was how little equipment it needed. It took me nine attempts to see the pattern. I would rather do one thing carefully than five things quickly.

A few details

I altered my mind about sensors twice while writing this. If you only take one thing from this, make it the part about sensors. The enclosure took longer than the electronics, as usual. I am still not sure I have it right, but it is closer.

For a long time I treated old radios as an afterthought. There is a version of this that is much more complicated. This is not that version. It took me four attempts to see the pattern. It is not glamorous, but it holds up. Most problems with e-paper displays turn out to be problems with time.

Low-power design is for the most part about what the device does not do. Half of the work is deciding what to leave out. I wrote most of this on a still Sunday morning. The result is not perfect, but it is candid.

What I kept

This is less a manual and more a record of what worked for me. If you only take one thing from this, make it the part about e-paper displays. Every summer I revisit the same questions about enclosures.

I like sensors that shows the marks of how it was made. The first six weeks were for the most part about unlearning. Little, repeatable steps beat big plans almost every time.

I keep coming back to circuit boards, for the most part because it rewards a steady hand.

I attempted the tiny version first. It did not last.