The ones with the antenna also have different circuit board. It has straight, flattened wires connecting the base with the segments. The ones without antenna have a kind of printed circuit. Marcin
On Feb 28, 2:18 pm, Jeff Thomas <nixich...@gmail.com> wrote: > Terry, your assessment was very good. > > From the volume of tubes examined over the years, the antenna-like > center support was used on tubes dated between 6350 and 6415. The > envelope is also a little taller. 6350 was the earliest production > date I'd seen. > > The underscore shape also varies from steep to shallow between lots > throughout the production period. > Most are relatively steep, with fewer than ~20% being shallow or > nearly flattened. > And requires some effort at matching if the underscore is illuminated > in the application. > > I've not seen any other visible differences aside from these you > pointed out. > > Regards, Jeff > > On Feb 27, 7:59 pm, Terry Kennedy <terry+googleb...@tmk.com> wrote: > > > > > > > > > I just completed an informal study of 50 or so B7971 tubes to see if > > there was a pattern to the different markings and construction. I > > figured I'd post it here in case anyone else finds it useful or can > > add to it. > > > The oldest tube I have has a date code of 6405. The newest one has a > > date code of 6823. > > > I have one tube with red print, in Burroughs-only (not Ultronics) > > marking. > > > The rest of the tubes have white print with a mixture of Burroughs- > > only and Ultronics marking. > > > The vast majority of the tubes have 64xx date codes. Presumably this > > was the initial production for the LECTRASCAN units. > > > I have 2 tubes with an "antenna" between the top mica sheet and the > > glass envelope. One of these is my earliest tube, a 6405, and the > > other has a 64xx (illegible) date code. This looks like an early > > production method used to position the innards in the envelope. > > > The underscore segments have a great deal of variation. Most of my > > tubes have a constant "steep" angle to the underscores, while a much > > smaller number have a shallow angle. I have a couple of in-between > > tubes as well. The variation seems to be due to not needing the > > underscore segment to line up with any of the other ones - if any > > other segment was mis-shaped, it would be very obvious. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
