I tried to make this nixie clock from this tutorial from instructables(there is also a schematic there for the board)
I followed all the steps correctly(or so I think) and the tubes light up but they seem to be ghosting or multiple numbers being displayed together. I tried to measure the voltage on the inputs when I set on my program for all the tubes to display 1 (D=0,C=0,B=0,A=1) and the voltage on A was 5V as expected but there was also 5V on A and C and B was sometimes 5V and sometimes 0.8V. I tried disconnecting the arduino and set the pins manually I connected DCB to ground and A to a 5V power supply but still the same issue. I don't know what else to look for(the rightmost tube is dimmed because someone recommended connecting a 33kΩ resistor). Could all 4 of the chips be fried ?
Check the high voltage power supply. If the voltage is too high then the clamp diodes of the driver chips cut in and you get multiple cathodes lighting on the tubes. I guess that about 170 volts is correct for those tubes.
That is a nice looking clock by the way. I have 3 working nixie clocks and the components for two more. One I published here: Six Digit Nixie Clock
Nixie tubes need at least 170V for ignition. Once a digit fires it drops the voltage (after resistor) to a burning voltage of 150V. That voltage then is too low for firing further digits. Check that your DC supply is not too high or increase the resistor value so that the anode voltage drops below 170V once one digit has fired.
Here below is the schematic from the link in the OP. The high voltage power supply is not shown but I guess that uses the same ground as the remainder of the circuit. Post a link to it anyway.
Another possible trouble shooting measure would be to choose one SN74141 chip, say the one belonging to the chip with the higher anode resistor, and use a probe to short out its pin 9 to ground while the tube is glowing. In the best case a digit 3 should show. I chose pin 9 because it is at the end of the chip and should be easier to identify.
EDIT
Someone (many thanks) has now supplied a more usable picture.
EDIT 2
There are some errors which have been pointed out in the associated video (link in the OP). For example the erroneous use of pins A6 and A7 as output pins.
Yes I have a common ground for the components. I tried the ground on pin 9 the digit seems to appear but I get the other overlapping digits as well. I couldn't find the power supply but I have the link from where I ordered it maybe you can extract some useful information it's set at 174V but the input on the nixie anode is lower: https://a.aliexpress.com/_EzG9oSy
OK. Two other things to suggest to help the trouble shooting.
Try the test again with with the SN74141 pin 9 shorted to ground but, at the same time set its pins A,B,C and D to high. Do you then get a clean "3" on the display ?
If not try to reduce the high voltage to around 150V.
Questions:
Are the SN74141 in sockets or directly soldered ? Removing one from the socket and again shorting pin 9 on the socket to ground may also show something.
Did you actually measure 174 volts with a meter ?
I tried both but it didnt work when I lowered the voltage the tubes dimmed. I measured 173.8V as input voltage to the tubes before the resistors, 124 with the 33kΩ resistor and 126 with the 10kΩ resistor. My drivers are directly soldered on I should have put sockets my bad.
Edit: I measured the input voltages of the pins(DCBA) to be 3.4 volts.
Outputs 8 and 9 = 2.9V
Outputs 2 = 2.1V
Outputs 3 and 7 = 9V
output 0 and 6 = 2V
Output 1 and 5 = 9V
Output 4 alternates between 8.5 and 0V
Any chance that you soldered the chips with an incorrect orientation ?
Did you get any spare chips with the batch you ordered to do some tests ? Anyway, post a link to the supplier of these chips.
Did you notice some of the errors listed towards the end of the video linked in post #1 ?
Did you do any basic tests on the tubes before soldering them although, having said that, it does not look like a tube problem. It really looks like the case when either NONE of the cathodes are grounded or ALL of them are.
Can you post more pictures including the underside of the board and some clear indication of how the high voltage power supply is connected.
EDIT
Did you use the supplied Gerber files for the board or make your own ?
This post crossed with your last edits to the preceding post.
If DCBA are 3.4v then these are HIGH which means no cathodes are grounded.
Better would have been to do the tests with one of the valid combinations of DCBA
from the table in the SN74141 data sheet:
I don't think there is a problem with the orientation they are correctly in place I think.
I got some spare chips on a separate board. I could desolder one of them.
Here is the supplier link: https://a.aliexpress.com/_EzCBhDe
(They were supposed to be k155id1's)
I saw the errors on the video. And I did the same fixes I didn't have a 2710 Ω resistor so I used 3 x kΩ and fixed the other problem as well.
I tested the tubes before inserting them they were working as intended.
The voltage is connected like this(I will provide additional photos below) : I use a 12V 1A DC barrel adapter.
Barrel female (+) -> board and HV supply
Barrel female (-) -> ground on PCB and ground on HV input and HV output
HV supply output 170V (+) -> 170V hole on PCB
(HV cables are reversed black is + and red is - for output HV)
Maybe that is the first thing to check. A reversed high voltage polarity could also cause such strange effects. When measuring the voltage with your multimeter you would notice a small, almost insignificant, '-' preceding the voltage reading ? Change over the multimeter probe leads to see if you notice a difference.
What board are the spare SN74141 chips soldered to. Maybe the board can be used as a test bed without de-soldering the chips. A test will be quite straightforward and the chips, anyway, would be no use in a breadboard.
The chips are soldered to an identical board just without the tubes. The power supply in the similar case seems to be exactly the same as mine the black is 170V and the red is ground on the output, the black(170V) is connected to the 170V on the pcb and the ground on the common ground with the others. When I measure the black wire with the red probe and the red wire with the black probe I get 170V and when I reverse them I get the minus infront.
OK. With the duplicate board (without tubes) you have I suggest this method of testing the SN74141 chips to see if these perform correctly.
The test involves disconnecting the high voltage power supply, choosing a single SN74141 chip and its associated empty nixie tube footprint and running a test with a led and series resistor with one end connected to +5v and the other end floating so be temporarily connected to any desired pad on the nixie foot print..
In principle, you'd send a control sequence to the SN74141 (ABCD) which would select one of the pins of the nixie tube footprint then touch the probe of the led circuit above to check that the selected nixie tube pin is connected to ground.
For example, if you send A=0, B=0, C=0, D=0 to the SN74141 then the pin on the nixie tube footprint for the digit '0' should be pulled LOW. The led connected to +5v should light when the other end is touched on that pin (pin 3) of the nixie foot print. Check also that the led fails to light if the pin, for example, for the digit '9' (pin 12) is touched.
Unfortunately, it is not unheard of that some rogue retailers will supply substandard and maybe even relabeled/fake chips.
Also interesting is when you discovered the polarity reversal on the high voltage power supply (red/black wires interchanged) . Was this before you first applied power to the board ?
I tried using the cables in reverse because I thought the black cable was ground the first time but I think the 12V DC power supply protected the board because I heard a clicking from it and I think it didn't provide any voltage but I will test with the new board and report back!
I tried 0000 with the other board with 5 V didn't work maybe it's really just some fake chips I ordered 4 new ones from eBay after I talked with the seller to verify they are real k155id1 to test them if I don't find any other solution but they will take a while to arrive.
It is very rare to find any instructables electronic project without an error in it somewhere. The problem is there is no one checking the content, and the authors are not as smart as they think they are.
When I look at the images you have posted then it is easy to see that the quality of your soldering is very poor, and likely to cause you problems.
That is bad luck but at least now you have the chance to install sockets for the chips.
If you haven't got a hot air station then my approach would be to snip the legs off the chips and use a soldering iron to melt the solder while tugging at the remaining piece of the leg with tweezers.
Then when all the leg pieces have been removed again melt the solder on a pad then blow through something like a ball point pen tube to clear the hole. Sometimes, counter intuitively, you have to add more solder to make this work. Clear up any solder splatter.
You can practice this technique on the spare board.
Or maybe you find a better idea on a YouTube video or someone here has an alternative suggestion.
I'd be reluctant to remove the nixies and use a fresh board because of the risk of damage to them while removing them.
Also, I'd correct the power supply lead colour code problem by swapping over the leads in the plug. You can usually do this with a miniature screw driver by gently pressing on the retaining clip in the window in the plug while simultaneously pulling the lead away from the plug.
Just out of curiosity can you post some close up images of some of the suspect chips
to see if there are any signs of a relabelling attempt etc.
**EDIT **
I have just had a look at the reviews in aliexpress of the retailers selling nixie driver chips sn74141 etc. Many of these complain about fake or otherwise non working chips.
I can't really say much based on single example but signs like the dimples having different diameters due to uneven sanding to remove the old markings can be a clue.
They will simply have taken any random chips with a 16 pin DIP package and relabelled them. This is my own experience with a different chip: Aliexpress retailer of rare chips - cautionary tale
Looking at the reputations of the aliexpress retailers selling the nixie driver chips, I'd say that the chances that yours are usable are very low.
