Attached is the schematic in PDF form. All lines except one seem to be common between all the tubes. Based on my guess of 135VDC tube supply, I think I was right. Tube drops about 72V when on, leaving 63V to be dropped by the total series resistance, 3600 ohms. 63V/3600ohm = 17.5mA. This is below the maximum rating of 25mA according to the 1C21 datasheet. It then looks like an AC supply to the grid would be required to cause the capacitive coupling that allows the tube to work as a touch trigger. I'm not too sure how to figure out this voltage.
On Friday, October 24, 2014 10:18:34 AM UTC-5, Joe Zatarski wrote: > > I will draw up a schematic of what I have in the panel now. I think it'll > probably be similar to what the otis docs show: resistor connected in > series with the tube, trigger and cathode tied together, and connections > for B+ and 'B.O.' (B.O. being the reference line for B+, which also happens > to NOT be at the same potential as ground, due to the AC supply tied to > it). There seems to be a cap, probably in parallel with something, but I'll > take a look. > > On Wednesday, October 22, 2014 4:51:21 PM UTC-5, Dekatron42 wrote: >> >> I think that the best thing you can do is to ask the company who replaced >> it if they can help you with any schematics, otherwise you will have to >> draw one yourself from what you have left of the elevator panel and we can >> take it from there, then you will know what voltages you need and you can >> do some experiments more easily. >> >> /Martin >> >> On Tuesday, 21 October 2014 21:00:47 UTC+2, Joe Zatarski wrote: >>> >>> I guess now what I would like to know are some example circuits for >>> power supplies maybe? I guess I need 135VDC, and it needs to be isolated >>> from the mains because it'll also have 150VAC on it relative to earth >>> ground. Easiest to do is get a transformer (if I can find the right voltage >>> output) but how about regulation? Is a properly sized zener diode good >>> enough? >>> >>> On Monday, October 20, 2014 10:41:47 AM UTC-5, Joe Zatarski wrote: >>>> >>>> So I found an elevator control panel in the garbage. They were >>>> replacing a broken one in the dorm next to mine. It appears to have 425A5 >>>> 'touch tube' trigger tubes instead of mechanical switches. I saw an old >>>> thread here about them which had a bit of info. I think you need to >>>> connect >>>> a 150vac supply between ground and the cathode, then 135vdc across the >>>> anode and cathode to use them as a touch button. There needs to be some >>>> resistance in series with the tube of course, and the 135vdc needs to be >>>> isolated from the ac. Also, I think the trigger input needs to be tied to >>>> the cathode somehow. >>>> >>>> I still have all the wiring in the panel as it was when I found it. >>>> There are 12 floors and a basement, so I'm thinking the buttons can >>>> represent the hour of a clock as well as an am/pm light. Furthermore, for >>>> setting the time, the tubes can still be used as buttons to type in the >>>> time. >>>> >>>> I'd appreciate if I can get some tips on driving circuitry and supplies >>>> since these are cold cathode neon tubes, something I have never dealt with >>>> before. >>>> >>>> -- 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/22bc4aa3-28c6-4688-806b-a37a52617d50%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Otis Elevator Schematic.pdf
Description: Adobe PDF document
