Category: Analog

My first working circuit that I designed was based on the Motorola MC1377. It’s a RGB to NTSC encoder. I am pretty certain I actually still have the chip stored away in my linear/analog microchip parts storage. Apparently they are still available NOS on eBay. I can’t claim that I designed it myself; I’m certain my best friend of the time, Jason G., likely had assisted and designed some of the circuit. At the very least he had a lot of input. It was decades ago, who has that kind of memory? Jason had gotten me interested in “the best” computer of the time. The Amiga 500. I don’t know if it was the best home computer of the time but it certainly was in front of the pack. A powerfully Motorola 68000 and color computing when the 8088 just got 4-color CGA! The Amiga had been around for a while why I bought mine; Long enough for me to buy a refurbished A500 from a commodore shop in north Kent/Tukwila, WA. Jason stayed overnight and we stayed up until the single digits of the morning building this circuit because I had not  yet saved enough money to buy the A 1084S monitor… the time had come.. my carpet sporting an extra burn mark from a soldering iron. I was 15 or 16 at the time and I usually soldered on the floor, there were already a number of burn marks by then. We powered up the circuit and plugged it into the Amiga and then my TV… Success! Well kind of.. everything was very purple but the output was perfectly usable. The start of my love affair with Amiga computers and a further solidification of my primary hobby; electronics.

I’m off to LA for some training this week. Hopefully I get some programming done on my projects. I brought a small “go bag” of electronics for out-of-town work. Hopefully the TSA doesn’t give me too much trouble. I’m sure a bag of electronics is a scary thing for those who don’t know what they’re looking at.

I am doing some experimenting with some small signal magnetics and a thought crossed my mind to ask the super-cool @tymkrs IRC channel gang if I was missing the boat on stripping enameled wire. Turns out I was….

Warning: I will not be held responsible for wives who are upset about missing emery boards.

The conversation:

<chasxmd>JohnS_AZ, is there a magic formula to removing the enamel off magnet wire?
<tautic|mobile>Stupid traffic
<mgburr|work>good exacto knife and scrape, or heat to 400f
chasxmd: hit it with your iron that is set higher then the melt temp
thanks for the tips, I've always gone exacto knife and felt there had to be a better way
<johns_az>chasxmd: I always steal one of Lisa's emmory boards. :-)
<johns_az>fine sand paper works well.
- scratch quit (Ping timeout)
<mgburr|work>all of the above

So I put these to test! I’m using 30 gauge wire that’s less than 10 years old and was redistributed by GC electronics.

Soldering Iron: Free air and solder pool.

Sanding: emery board and 220 sand paper

Exacto-Knife scraping.

Not tested, but possible future ideas: Blow torch, actually googling to see if there is a tool the industry uses.

So scraping takes a while and it leaves small strips that you end up having to sand or rotate a 30 ga wire and get lucky? On 30 gauge wire, forget about it.. a waste of time.

220 sand paper? probably a lot better on 18gauge+ enameled wire but for small wire it was a hassle and took way too much time testing the conductivity and making sure I had gotten at least almost all the enamel off.

The two reasonable methods for my wire were my wife’s emery board and the soldering iron.

The emery board was the shortest method. I removed a 1/2 inch* section of enamel in just under a minute**.

The soldering iron was looking like a bust because I was free-air rubbing the wire to the tip of my Weller soldering station with some fresh solder on the tip. At 1:15 I hadn’t made a dent in the enamel. I trend grabbed a piece of copper clad board and added a little solder and rubbed the wire with the soldering iron and it turned out okay.

* I live and work in the USA. I use measures of units that I was born and raised on; It’s not lost on me that this is inconvenient for you non-US persons.

** I wasn’t cracked out on caffeine and I was just taking a leisurely relaxed pace through this process.