 What is it? This is the second GeekKlok I've built to use some of the 13 Burrough's B-7971's I was given by my father. To get a little more background on both the GeekKlok PCB kit and how I got that jackpot of tubes, check out my write-up of the first GeekKlok I built. In this version, I had the distinct goal of a wall mounted clock. I can't escape my starkly utilitarian tendencies, and opted again for a boxy, entirely machined case. For a little bit of drama, I included a pair of blue LED back-lights behind the PCB, which is in turn behind the tubes. Believe it or not, the LEDS are actually towards the bottom and the center of the PCB. It is an artifact of the fly-cutting finish on the back plate that makes it looks like the LEDs are at the top and a quarter of the width from the edge. It would be fair to ask why I decided to build a second GeekKlok instead of spending my resources on something new or self-designed. I honestly debated that myself, but I just grew to like the first one so much, I found myself wanting another for my office at work so I'd never be far from the glow of a B-7971 nixie. I figure two versions of my favorite clock isn't that ridiculous, and I still have four tubes (and a spare) left for a self-designed project I have brewing.  How does it work? Well, just like the first did! The major difference with this version came from my goal of having it be wall mounted. Since I always try to display the electronics involved in making something work, I mounted the PCB directly behind the tubes, then ran wires from the PCB to the tube sockets. Since I wanted to make use of the sweet vintage sockets that came with the tubes, I decided to make a base plate out of delrin so I could easily machine a pocket to conceal all the wiring beneath the tubes. The delrin base plate is independently attached to the back plate so I could assemble the PCB, back plate, and base plate and do all the wiring. With all that in place, the rest of the case assembles around the back plate.  In the end, I really like how the base plate turned out. It is very rigid, but lightweight thanks to the deep pocket. Even though I was able to remove quite a bit of material, I still only had 0.400" of depth to work with, and I had to bring 18 wires through each of the four 3/8" slots. I figured using some very thin wire would make everything easier. Unfortunately that logic should only be taken so far, and 32 gauge teflon insulated wire was too far to take it! It took forever to make each of the solder connections, then fish the bundle of wires through the slot in the base plate. A few hours and more than 68 identically colored wires later, I was pretty darn happy. I taped all the wired down so they wouldn't get pinched as I assembled the case. All that effort is now completely hidden, which is just what I wanted!  To be totally honest, I'm still not sold on the blue LED backlight. It certainly adds a bit of interest, but I haven't been able to make a gentle, diffuse light. Because of the finish created by fly-cutting all the surfaces, the light tends to reflect in a peculiar way that always makes two bright spots that move around depending on what angle you look at the clock from. I might play around with some tissue paper or something to make a light diffuser, or I might just be lazy and leave it be... A few more photos:  A lifeless shot that does a good job of showing the case.  Delicate wiring! Compare the 22AWG blue wire to the 32AWG black wire.  |