The solder I use is Kester 44. The rosin/flux it has can be cleaned with either denatured alcohol or acetone. I've read that some people use isopropyl alcohol. The key is how concentrated is the stuff. If its alcohol, make sure its at least 90% alcohol,The isopropyl from the drug store is only 70%, and only 50% from the dollar stores. I buy my alcohol and acetone from the Home Depot. Klean Strip brand "denatured alcohol" is ~ half ethanol (the stuff in gin and beer) and half methanol (wood alcohol).
On small boards, I just use acetone. The reason for having both, is that they evaporate at different rates. On larger boards, I start with alcohol, and let it soak a little. The alcohol takes a little longer to dry. I use a stiff tooth brush and a pair of shot glasses. One with alcohol, and one with acetone. I dip the brush in the alcohol then scrub the board with it. Once the really nasty crud is gone (or at least spread around), switch to the acetone. Dip and scrub until the dried board is no longer sticky. Brush in one direction, so that the tainted liquid sprays off the edge of the board. If you still are having ghosting issues, after the board is really clean, with no sticky residue, then contact me thru the eBay messaging system. Also look at the clock's instruction page. Its updated regularly. Maybe, there's a note, that's been added since you viewed it last. https://threeneurons.wordpress.com/nixie-power-supply/nixie-clock-kit-microcontroller/ On Thursday, February 11, 2016 at 5:22:11 PM UTC-8, threeneurons wrote: > > Well I'll go to the end, with the solution ... Clean your Boards !!!! > > Back to the beginning. I'd been selling some multplexed nixie kits for > close to a year and a half, now. It uses a unique form of multiplexing > called "Charlieplexing", invented at Microchip. There it was used for > driving LEDs. A clever member of this forum (when it was back at Yahoo), > named Jason Harper saw that it could also be used to drive the base-emitter > junctions of transistors, back ~2003. For our pleasure, base-emitter > junctions, of HV transistors. In short, charlieplexing nixie tubes. That's > what I incorporated in my kit. > > One important issue with charlieplexing, is that it can only be done with > uC tri-state I/O bits. It needs the I/O bit to not just output a one (1) or > zero (0), but also present a high-impedance (Hi-Z). With charlieplexing, > only one "node" (p-n, or base-emitter junction) of its matrix can be active > at any time. One output issuing a "0", while another issuing a "1", with > the rest "inactive" and presenting their Hi-Z state (DDR bit set to > "input"). This becomes a key to the problem later. > > Multiplexing, in general, and not just charlieplexing, can exhibit a > problem called "ghosting". This is when more than one numeral appears to be > ON at any time. Usually, the intended numeral is on brightly, while a > second numeral is only slightly glowing in the background. Hence the term, > ghosting. It can have multiple causes, that usually boil down to something > being ON at the wrong time. A timing issue. This isn't an issue with direct > drive displays, since they don't rely on timing. > > Now to the problem at hand, and its inadvertent solution. A customer > returns a board (for evaluation) on what's causing his ghosting problem. I > turn it on to confirm the problem ... yep, ghosting. Pretty severe, too. I > examine the board visually, but all the parts are in the right place, and > the solder joints look okay. So, before probing around further, I decide to > clean off the flux residue. When I'm done, I let it dry for a half hour, > before applying power. Turn it On ... no ghosting. Apparently, the flux > residue (and whatever contaminants it trapped) was conductive enough, to > turn ON, inactive "nodes" (transistors). > > In conclusion, clean the flux residue off the board ! > -- 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 [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/f41b230c-15ff-45ed-9408-41b88af28f2b%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
