The electronics for a direct drive B7971 clock are now complete. The clock is based on Moses’ (Neonixie.com) controller and 6-tube schematic except I have substituted CD4511 7 segment decoders/drivers for the 74141’s, added dual John Taylor Edge1364 180VDC 45ma SMPS’s ( one per each bank of 3 tubes), and SmartSocket PCB’s socketing each tube and hosting each respective tube’s MPSA42 transistor/resistor switching network. Tubes are REALLY nice and bright!! It’s a welcome change to see these tubes direct driven vs. multiplexed for a change...even with the basic block font they’re still cool! I have newfound fondness for the B7971 and it’s utilitarian, functional beauty! Case design is in the works. The finished product promises to be another MONSTER clock!

OK, I’m pretty excited about one of my next Nixie projects. I have recently acquired some of the gorgeous and extremely rare French F9020AA Nixie tubes. These tubes are unique in the Nixie world as they are a flattened, oval shaped Nixie tube with very large digits. The tube’s shape will present a unique set of circumstances as relates to building a case for them, but I am anxious to begin the process. This clock is stalled until further notice.

The Nixie Rejuvenator: This thing really does work! It’s nothing more than a Variac capable of generating at least 180V and a bridge rectifier to turn the AC into DC coupled to the appropriate current limiting resistor. Thanks to Dieter Wechter of Chronotronix for his advice on how to do it.  The idea is to revive cathode poisoned digits by overdriving them with approximately twice the current for extended periods of time. The exposure time varies considerably from one digit and tube type to another depending on the extent of the poisoning. The downside is the process can be a painstaking one. It’s really not worth doing on the lesser more available tubes, but for tubes as rare as the Z5680M, for example, it’s well worth the time and effort.

I recently used this gizmo to evaluate the INS-1 neon tube for use in an upcoming clock as a colon separator. It is widely held in the Nixie community that this tube is extremely unstable and prone to flickering after a few hours of introduction into a circuit. After 7 days of testing these little dudes I can honestly say, I agree 100%. Out of 20 samples I found just 4 that are acceptable for use in this application. I found that using a 470K ohm resistor with a 180VDC supply ( required for my application) seemed to work best. This resulted in an operating current of just under the recommended 0.5 ma. BTW, I used this tube as a pilot light in my ArtDeco and Moderne nixie clocks and had really good luck with it. I guess I got lucky because the ArtDeco has been running for the last 7 months and the Moderne 3 months with no flickering!

FYI: Here’s a short clip from the 1980 film ‘Dressed to Kill’ with Angie Dickenson. Checkout the VFD clock! This movie is responsible for me getting hooked on Nixie/VFD clocks. And, check out Angie, she was a total babe!!!