I designed a Nixie clock using TTL in the early 70’s which used a transformer inside the case along with a voltage doubler circuit for the HV. It ran nicely for 35 years until it was consumed by a fire. My best guess is that one of the voltage doubling capacitors failed and ignited. The clock had a 1A fuse on the transformer primary and secondary, both of which eventually opened but not until after the old paper electrolytic caps heated and ignited the wood and plastic case. The circuit main breaker (15A) never tripped. I was lucky to have suffered only smoke damage and a destroyed clock and counter top.
While I am not saying that my overall design was horrible, I will no longer bring 120/230v mains voltage into any housing (that runs unattended 24/7) when there are UL/CSA/VDE bricks or wall warts that are thoroughly tested and engineered to eliminate exactly the hazard described above. While there may be no issues with the module you are looking at, I would not use it because it brings the full main power into your housing. After my experience, I would prefer to eliminate a melt-down inside of my housing. The HLK-PM01 does not provide me with the safety factor that a wall wart or brick provides. IMHO, life is much better when you keep the main away from the inside of your clock. If you need to use the main as a time base, you can just go with an AC wall wart or use one of many perfectly good crystal based chips or GPS solutions for timing. Even though I had no problems for 35 years, I blame the presence of the main power, inadequate fuse protection and a design that was intrinsically unsafe, as the reason for the fire. From: 'threeneurons' via neonixie-l [mailto:neonixie-l@googlegroups.com] Sent: Wednesday, June 29, 2016 1:47 PM To: neonixie-l Subject: [neonixie-l] Re: HLK-PM01 Most of us, like bringing in low voltage into our nixie clock, or other nixie project. Then boosting that low voltage to the 170V, or more, to power the nixie tubes. That way the bulky "wallcube" stays by the wall outlet, and only a skinny cable goes to our clock. My major concern with the AC wall power is safety. Fire hazard more than shock hazard. As long as the electronics is enclosed, there should be no, or little electrocution hazards. But the fire hazard remains. If you use a wallcube that passes your local safety agency standards, then the hazard stops at the wall. If the output leads of a "safe" wallcube are shorted, it will never get hot enough to ignite anything, and it usually dies quietly, and safely. If you do bring the AC line voltage directly into your "box", take measures to reduce the chance of fire. Use a detachable cord, with it's mating connector on your box. Something like an IEC connector. They have cords, with the other plug that matches most of the countries: <http://www.futurlec.com/Pictures/IECMALESOCKET.jpg> This way if somebody kicks the cord, it disconnects the power, instead of pulling internal wires, and causing a short. A fuse, with holder should be added, too, just in case of overload, or short. Mike Harrison, has a nixie clock that uses 4000 CMOS logic, and draws very little power on the low voltage side. So his, is powered without a transformer. For the high nixie voltage, the AC is simply filtered, and rectified. Nixies don't need a precise voltage. The make sure its over 170V, and that each tube has a current limiting anode resistor. Value of that resistor depends on the nixie tube type, and the actual supply voltage. On Saturday, June 25, 2016 at 9:04:45 PM UTC-7, rubli wrote: I am making a nixie clock from scratch, I am planning to use this module, so I don´t need any bulky tranformer: http://smart-prototyping.com/Ultra-compact-power-module-HLK-PM01.html anybody has experience with this power supply ? thanx !! -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To post to this group, send email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/2e302be9-6b79-4989-896d-d4fe98ebbf2e%40googlegroups.com <https://groups.google.com/d/msgid/neonixie-l/2e302be9-6b79-4989-896d-d4fe98ebbf2e%40googlegroups.com?utm_medium=email&utm_source=footer> . For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/57749f84.177c240a.b6c52.056c%40mx.google.com. For more options, visit https://groups.google.com/d/optout.
