Yesterday, I tried my hand at soldering a new prototype HV programmer, with much success. After watching some YouTube videos on soldering, I had a strong theory on what may have been my problem in making solder bridges: I was using a rather wide tip at a high temperature, which resulted in spreading too much heat around. That’s why I kept running into issues where the surface tension kept working against me. I read a tip that lowering the iron’s heat to about 300C (some even suggested as low as 250C) would help a lot on making bridges. On top of that, I switched to my smallest tip to help reduce the heat transfer. Those two changes combined now allowed me to add some solder to existing connections without melting too much.
Above you can see the first tryout of making solder bridges. As you can see, some are better than others. The line on the left is quite sloppy, but still effective. I’m much more pleased with that triple row of solder bridges in the middle, for instance. Nevertheless, as I was soldering the set, I would use my multimeter to check the connection as soon as I had finished a line.
In the end, I was quite pleased with the final product. It doesn’t look as clean as I would like, but it looks neat, at least. It’s also a great first attempt at doing this properly. This is something I can build on, and I feel quite proud of myself.
The topside of the board looks quite neat, now that most of the connections are solder bridges on the underside. Apart from learning to make those solder bridges, I also improved on my method of laying jumper wires on top of the board. Partly thanks to my new wire stripper, and partly due to being a little less parsimonious, I ended up with exact straight wires. Before, I tried to cut them perfectly to size to start with. Now, rather, I strip more than I’ll need from one end, cut the insulation exactly to size, and then use a wire cutter to get the jumper. This way, I use a little more copper wire, but it’s also far easier to cut to exact size by just trimming the excess leads. There are only two things I’m less happy about: firstly, the resistor on the top-left is not flush with the board. While trying to solder it down, it slipped and I just couldn’t easily get it back down. Secondly, the LM7808 is slightly askew. It works fine, but it’s just a little sloppy.
Clearly, when comparing the first to the second prototype, the second is much cleaner by far. For one, of course, it has fewer components, so it’s easier to look less cluttered. Secondly, though, just not having that mess of wires makes all the difference.
Now, the big downside is that I haven’t seen it confirmed to work yet. From what I can see, all the connections should have been correct. So, to troubleshoot, tomorrow I’ll first have to compare my schematic to the original version to see if I made a mistake there. Secondly, I’ll have to one-by-one check my connections to the schematic. After that, I’ll check the voltages and continuity on each connection with my multimeter to see what’s happening. If that doesn’t give me any answers, I’ll have to use my logic analyzer to see what’s happening when I press the button. (EDIT: while I previewed this post after drafting, I noticed what is the most likely issue. Pin 4 on the master IC is not connected to the ground bus – the long vertical line. Comparison the soldering job to the schematic shows this quite clearly).
However, even if it doesn’t end up working, I really am proud of the neatness of the solder job. I felt so much more comfortable doing that, and it was incredibly enjoyable to do now that it was working well. I’m sure that with more practice, I’ll get those lines looking neater and neater as time goes by.