30,0000 hours is just over 3 years i never saw a nixie tube fail in so short a time;or go totally black from sputtering for that matter,nixie's can be run for 10 years with no visible discoloration ,i have done so,any others?
-----Original Message----- From: neonixie-l <[email protected]> To: Digest Recipients <[email protected]> Sent: Wed, Apr 25, 2012 1:29 am Subject: [neonixie-l] Digest for [email protected] - 8 Messages in 4 Topics Today's Topic Summary Group: http://groups.google.com/group/neonixie-l/topics Nixie life specs [1 Update] Hazy tubes, 74141 [4 Updates] Dallas/Maxim TCXO [2 Updates] Interesting TI digital clock on eBay [1 Update] Nixie life specs "JohnK" <[email protected]> Apr 25 05:56PM +0930 I have noticed many discussions about the lifetime specifications of Nixies. I haven't noticed anyone quoting the manufacturer definition of lifetime - but I may have missed it. So, read on ....... "Electronic Counting circuits techniques devices ", Mullard Limited, October 1967. approx. 220 pages. Many circuits. Various authors and sources. There seem to be about eight of these books available through ABE ranging $20 to $60. Bound to be others at the usual places too. The approx 13 page chapter on numerical indicator tubes is based on material supplied by B. Butler of the Mullard Industrial Electronics division. I have included some of the text below rather than attach scans [if allowed], John Kaesehagen Australia. >From the 'numerical indicator tubes' chapter I quote this [via OCR] :- "The normal figures quoted in published data for the life of a numerical indicator tube are 5000 hours with a continuous display of one character, and 30 000 hours when sequentially changing the display from one digit to the next every 100 hours or less. The end of life for the above figures is taken to be the time when any character is unable to be covered completely, although several more thousand hours would probably have to elapse before the character became completely indecipherable." The above is contained within this section:- " LIFE PERFORMANCE The expected life performance of a numerical indicator tube depends to a greal extent on the length of time the discharge is investing any particular cathode. With any gas-discharge device, the cathode is subjected to constant ion bombardment which removes material from the cathode and deposits it elsewhere in the tube. This "sputtering" process, as it is known, is, in fact, put to good use in many cold cathode gasfllled tubes during processing. The cathode surlaces are cleaned in this manner and any sputter material thrown on the glass walls of the envelope effectively seals in any foreign matter that may affect the performance of the tube during its life. In a numerical indicator tube, however, although a clean cathode is desirable, sputter material on the envelope would impair the visibility of the display. Some sputtering is unavoidable, but since the rate of sputter is proportional to the peak current of the tube, it can be contained within limits. If one cathode is continually glowing, sputter material from that cathode is deposited on other cathode surfaces in close proximity. Although the legibility of the glowing cathode is not affected to a great extent, the cathodes on which the sputter is deposited are affected. In fact, the work function of the metal of the adjacent cathodes alters in such a way that it requires a higher current to completely cover the cathode and if this current is not available, the cathode appears patchy. This imposes a minimum permitted current level on the tube. It is possible that complete erosion of the cathode may result from bombardment, but this is unusual. If the discharge is cycled betweerr characters fairly regularly, this gives a very much improved life figure since each cathode, although receiving some sputter material, is subjected to the cleansing action of bombardment. In this case, the higher the current, the more effective the cleansing. The viewing area of the envelope is protected from sputter material by the use of a shield, or mesh, which is usually connected to the anode. >From the foregoing it is evident that the end of life of a numerical indicator tube is not abrupt, but takes the form of a gradual deterioration of a character. This is convenient, because it enables a tube which is showing signs of deterioration to be replaced before it fails completely. The normal figures quoted in published data for the life of a numerical indicator tube are 5000 hours with a continuous display of one character, and 30 000 hours when sequentially changing the display from one digit to the next every 100 hours or less. The end of life for the above figures is taken to be the time when any character is unable to be covered completely, although several more thousand hours would probably have to elapse before the character became completely indecipherable. If a tube is operated with a bulb temperature below 0"C, the mercury inside the tube condenses, resulting in a slight increase in the sputter rate. However, if the consequent shortening of life can be tolerated, an operating temperature range of -50 to +70"C can be achieved. " Hazy tubes, 74141 StoopKid <[email protected]> Apr 24 11:40PM -0700 I'm using 6 IN-14's and 6 russian 74141 equivalents. My PCB is already made and when I want a tube to be blank I just throw it an invalid code. But now I'm realizing that this it making them appear hazy instead of off, like all of the digits are firing between one another. This goes away if I turn down my voltage but to make it stop, I have to turn down the voltage low enough so that some of the numbers don't completely light up. Is there anything I can do about this? StoopKid <[email protected]> Apr 25 12:03AM -0700 Here is an image of what I'm talking about. To turn off the haze I need the tube to be at 139volts across the tube. To completely light up that 2 I need 142 volts across the tube. The problem seems to follow the tube wherever I swap it to. On Tuesday, April 24, 2012 11:40:48 PM UTC-7, StoopKid wrote: StoopKid <[email protected]> Apr 25 12:06AM -0700 http://i.imgur.com/iXRL7.jpg Here's an image of what I'm talking about. To get rid of the haze I have to be below 139v across just the tube. To light up the tube I have to be above 143v across just the tube. The problem seems to follow the tube when I swap it. Should I have something in my circuit to drain this current when the tube isn't on? On Tuesday, April 24, 2012 11:40:48 PM UTC-7, StoopKid wrote: David Forbes <[email protected]> Apr 25 12:42AM -0700 On 4/24/12 11:40 PM, StoopKid wrote: > away if I turn down my voltage but to make it stop, I have to turn down > the voltage low enough so that some of the numbers don't completely > light up. Is there anything I can do about this? Unfortunately, you don't have many good choices. You can keep all digits lit at all times, or make new boards with anode switches. The former is a lot easier. Chalk it up to experience. -- David Forbes, Tucson AZ Dallas/Maxim TCXO "chuck richards" <[email protected]> Apr 24 08:34PM -0700 As some of you know who have read this thread before, I have used these Dallas/Maxim DS32KHZN/DIP TCXOs exclusively in my clock experiments since they became available back around year 2000 or so. They have always proven to be very stable, but not always tuned to the exactly correct frequency. A typical prototype clock I have running with one now gains about 1.2 seconds every 14 days. Well, I finally decided to do something about that. I calculated how many extra pulses it is making over those 14 days, and divided that number by 14 and then again by 24 to arrive at the extra pulses per hour. That number turns out to be 117 pulses to somehow remove every hour. I made a pulse remover. It's a very simple affair that uses a 4040 ripple counter, a 4073 triple 3-input AND gate package, and 1/2 of a 4013 D flip-flop. It is set up to decode count 117 (75 hex) (0111 0101 binary). Upon decoding that count, the flip-flop is reset. When the flip-flop is reset, it holds the 4040 counter at reset as well. During the time the counter is running, the outgoing pulses are gated off to the clock's counters via an AND gate. It works because I tested it triggering the flip-flop every second instead of every hour. During that test the clock lost exactly one second in 4 minutes, 40 seconds just as the numbers say it should, if the pulse remover is working. So after having tested it this way I moved the lead over to the input to the hours counters, so that the pulse remover gets to run once per hour. It's still too early to know whether or not this pulse remover will only be triggered when it's supposed to be and at no other time due to noise. But if it can be made to operate correctly, I think it can hold the possiblility of drastically (as in orders of magnitude) improving the accuracy of this TCXO. A slightly more complex version can be made that has the integer that represents the number of pulses to be removed to be set in on two tiny hexadecimal rotary dip switches. That would provide a resolution of one pulse, and be selectable from 0 to 255 pulses removed per hour. It appears that finally there is an accurate and fairly simple way to adjust the speed of these clocks. The first version of this circuit uses only 3 dip packages. If all works well, this can be retrofitted into all of my clocks by making a little add-on board and installing it. This thing will even provide a way to compensate for crystal aging. Time will tell. Just thought I'd run this past all of you. I am sure most of you already have heard of such pulse removing ideas before. If a slow one was ever encountered, a "pulse stuffer" could also be made to correct that. Chuck $4.95/mo. National Dialup, Anti-Spam, Anti-Virus, 5mb personal web space. 5x faster dialup for only $9.95/mo. No contracts, No fees, No Kidding! See http://www.All2Easy.net for more details! John Rehwinkel <[email protected]> Apr 25 12:13AM -0400 > That number turns out to be 117 pulses to somehow remove > every hour. You could attack it a different way, and skip one pulse after every 1008246. Shouldn't be hard to implement, as that's just 2 * 3 * 197 * 853. You could instead skip one out of 1008247, but that happens to be a prime number. - John Interesting TI digital clock on eBay Charles MacDonald <[email protected]> Apr 24 03:44PM -0400 On 12-04-23 09:58 AM, Terry S wrote: > much: > http://www.ebay.com/itm/130684969032?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649 > Not mine, nor will I be bidding. I think that was their only attempt in that market. I used mine for years, but any power glitch and it lost track of the time. The day I was late for work because of this, was the day I went back to a mechanical alarm clock. -- Charles MacDonald Stittsville Ontario [email protected] Just Beyond the Fringe http://users.trytel.com/~cmacd/tubes.html No Microsoft Products were used in sending this e-mail. You received this message because you are subscribed to the Google Group neonixie-l. You can post via email. To unsubscribe from this group, send an empty message. 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