I just took another look at the schematic you provided, you're right.
You don't need to do cathode side blanking. For some reason, I thought
that you had both nixies in the pair connected to the same 74141 and
would need to blank cathode side in order to address a single nixie.
Since you have each nixie in the pair connected to a separate 74141, you
should be fine.
-Adam
On 3/26/2012 12:13 PM, Imbanon wrote:
Indeed, I see you got it right :)
Anyhow, I got it all fixed. I just lowered the power supply to 180V.
Of course, I had to recalculate all the anode resistors (finally have
individal anode resistors), but the blanking now works just fine.
But still, I don't understand why I should blank one nixie in an anode
pair, like Adam suggested. Also, sequence like that will cut the duty
cycle by half, meaning I would need to increase the current peak, and
lower the tube life. It does seem to work fine as is.
Ok, Good luck.
Thanks a lot!
On Mar 22, 11:27 pm, Cobra007<[email protected]> wrote:
It's an interesting combination those 2 npn transistors. The signal on
the base is actually inverted compared to "normal" npn/pnp
transistors. When T2, T3, T5 are switched off, the tubes are actually
on :-). That's also where your leakage problem comes from if you ask
me. You choose 220k resistors, which means the lowest possible anode
voltage is half the supply voltage (215V / (220k + 220k)) * 220k =
107.5V. You better choose a lower resistor that goes to the collector
of T2, T3, T5 (maybe 100k). This will bring the anode voltage down to
about 68V.
I don't have a price yet for my modules, they won't be expensive of
course but I need to wait until I have a finished product.
Michel
On Mar 23, 5:00 am, Imbanon<[email protected]> wrote:
Sorry about that. I thought it was an universal shematic file type,
'cause they are all .sch
Here's the pic http://www.mediafire.com/download.php?5903q1ur3inc729
Cheers
On Mar 22, 4:14 pm, Adam Jacobs<[email protected]> wrote:
Would you mind converting that schematic to some kind of image file? Is
that an eaglecad file?
blanking on the 74141 will cause leakage if the supply voltage is too
high. Are you using real 74141's or the russian kind?
From that picture, I'm not sure if that is leakage.
-Adam
On 3/22/2012 5:19 AM, Imbanon wrote:
Hey all
I found some time to make a schematic. It only shows the two 74141,
nixie tubes and anode drivers.
I also tried blanking nixies via 74141. I would have never guessed
that you meant on hex code, as I am doing this on an arduino :)
Blanking nixies with 74141's give me a lot of leaking (or at least I
think thats leaking), so I'm not so sure about using this method. But
I do think that it's maybe possible to divide the leaking to the rest
of the nixies by adding a resistor for each anode, instead of sharing
them. See for yourself in the links.
http://www.mediafire.com/download.php?bbx4z4k5vjul56b
http://www.mediafire.com/download.php?ym4s96yeusrm9sy
So I guess my next move should be to remove the trimpots, and replace
them with actual resistors for each anode.
But what should I do with the blanking? To be honest, I would leave
the setup as is, because it seems to work fine. But if you guys think
I can do something better to get a longer tube life, I will make
changes to the schematic immediately.
Thanks!
On Mar 19, 12:04 am, Dylan Distasio<[email protected]> wrote:
I'm very interested in hearing more about this module...Are you saying you
are having this custom manufactured? If so, how have you found a way to do
this economically?
On Sun, Mar 18, 2012 at 6:31 PM, Cobra007<[email protected]> wrote:
For my clock I am designing a module as I am not really a fan to use
these types of old TTL logic. It's a 24 pin module that fits into a
DIP24 IC socket. It basically mimics the 74141 but has high voltage
output mosfets (240V) and the 4 inputs can be latched, so you don't
need extra latches as required by the standard 74141. It also offers a
blanking input, either by writing 0x0a or using a dedicated pin (which
is convenient for PWM dimming). It can be interfaced with MCU or
arduino.
Michel
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