JIMMIE wrote:
On Apr 19, 2:00 pm, Bruce W. Ellis wrote:
On Wed, 8 Apr 2009 06:51:53 -0700 (PDT), Tim Shoppa
wrote:
On Apr 3, 10:34 am, JIMMIE wrote:
I have a Systron Donner frequency counter that uses Nixie tubes. The
counter works fine but I am forever replacing the Nixie drivers
74141s. I started to use it this AM an one was out. Is there a
replacement for the 74141, I couldnt find one, or is there a circuit I
could build on a DIP header to replace them. I could probably design
one but I wanted something tried an tested as I dont want to put my
counter board at more risk than I have to.
Domestic 74141's are hard to find these days but on E-bay the Russian
equivalent is very common.
Yes, you could build just about anything with a one-of-ten decoder and
some current-sink drivers to do the same.
If the goal isn't nixie tubes but is a working frequency counter, you
could probably put the counter up on E-bay for somebody who wants
nixie tubes, and use the money to buy several superior frequency
counters.
Tim N3QE
Just remember to cut down on the voltage and current to the nixie
tubes and the 141s will last forever...
Bruce W0BF- Hide quoted text -
- Show quoted text -
Thanks all for the input. I managed to cut the voltage back from about
210VDC to 185VDC and the display still looks good, the change in
brightness was barely discernable. It may take a while to see if this
helped. What voltage do you normally run on nixies. I wish I had more
data on the nixies but I dont have a part number.
Yikes, 210V sounds high. I just took a look at the old 1985 databook
from TI. It does not state an abs max off-state voltage but under
recommended operating conditions it says 60V. If memory serves me right
mine used to run around 150V.
This datasheet says 60V minimum and it appears there are zeners built in
that limit what the 74141 output transistor sees:
http://wiki.cecs.pdx.edu/pub/JoeProj...lock/74141.pdf
Probably that zener is low enough in voltage not to fry the transistor
yet high enough that the nixie element will extinguish. BTW there are
lots of 74141 on Ebay for around $0.50-$1.00 in medium quantities. Looks
like they are from Russia.
--
73, Joerg