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Mounting frame

I took the Scotty's advice of building everything into a large blank PCB. You cut holes in the board in exactly the same size as each panel. When you're ready to install a module, you solder a few spots around the perimeter. These hold the module in mechanically and help ensure a solid ground. Later, when I'm sure it's working in concert with everything else, I'll solder on a fence to isolate everything. To make the frame, I decided to design a graphic from the layout image above and iron-transfer it to the PCB. After, I'd use that as a guide for cutting out the holes.

[caption id="attachment_804" align="aligncenter" width="540"] First (failed) attempt[/caption]

My first attempt was simply mirroring and printing the diagram as it was. The lines were relatively thin, and I don't think there was enough toner to really grip. Also, I was figuring out the other day how long it had been since I attempted a toner transfer… it's been about 4 years, so I'm a little out of practice.

[caption id="attachment_817" align="aligncenter" width="545"]![](http://alternet.us.com/wp-content/uploads/2010/04/Master- layout-print.jpg) Cutout guide (click for PDF)[/caption]

After another failed attempt, I decided to make the background black and the modules white so there was plenty of toner to bond to the PCB, and I can extend and estimate where the border is. This worked much better, though there were still many holes. I'm not really sure what I'm doing different. I couldn't find my old stash of glossy photo paper, so I tried Kodak paper for the first try (bad results). My friend suggested using a page from a magazine (about the same as the Kodak paper). The "good enough" result was using the updated image and magazine paper.

[caption id="attachment_805" align="aligncenter" width="540"] Finally good enough.[/caption]

Using this extra information, I filled in some of the gaps with sharpie and headed out to the shop. I made corner holes for each module hole, and tried to cut the flats with a coping saw. While I finished a few that way, it was a painful and slow-going. Later, I used the dremel again with a carbide milling bit. This method went very quickly , though there was more wavering in the final cut. I cleaned each of the holes with sandpaper and enlarged them enough for the modules to have a mostly tight fit.

[caption id="attachment_806" align="aligncenter" width="540"] Cleaning the frame[/caption]

Once I finished making and refining the holes, I cleaned-off the toner. After the toner was all cleaned-off, I soldered the entire surface. It took forever, but I needed to make sure that it didn't oxidize, preventing soldering later. With the entire surface "tinned" I put it in the toaster oven to smooth everything out.

[caption id="attachment_808" align="aligncenter" width="540"] Master Oscillator mounted[/caption]

While in the toaster, the bottom side of the board, which I'm not going to solder on, developed a pretty oxide layer. In the above photo, I have the master oscillator installed. I'm still not totally sure if it's 100%, and I still need to solder on one more connection to it, but once those things are taken care of, I'll solder on a cover.