Zero digit went out, day later one digit went out. IN-8-2

[Kyle Mikolajczyk]

Hello All,

I recently purchased a kit to make an IN-8-2 clock. It has been working without flaws for almost 2 months. Yesterday the 0 digit stopped working, and in the photo you can see it is now lighting up only on the floor of the tube. This morning, the 1 now went out with same effect. 

What do you think is the cause of this? I do not think it is a driver as the other tubes are fine. 

Any way to salvage the tube?

[Dekatron42]

The soldering on the pins looks like it needs a rework, the holes are not filled with solder, try to redo them and see if that changes anything.

/Martin

[Kyle Mikolajczyk]

They are soldered on the other side of the PCB. Besides there is illumination on each digit that is not working. It's just on the bottom as seen in the photo. So there is pin contact just fine.

[Kevin A.]

Just because there "is" solder doesn't mean that you don't have a cold solder joint. This board appears to be poorly soldered just from this one photo. Each through hole should be filled up to the top side of the board. Get some high quality eutectic solder, apply flux (prerferable water soluble, such as amtec 4300lf), reflow all the solder joints and add solder where necessary. This should take 10 minutes and may immediately yield results. If not, then further steps should be taken to troubleshoot. 

--
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 neonixie-l+...@googlegroups.com.
To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/b2ce62ca-9fba-40d4-b704-4d82e8e50061n%40googlegroups.com.

[gregebert]

Wiggling the tube should confirm a poor solder connection.

[Kyle Mikolajczyk]

I re-soldered the tube. While I was doing it I found this black soot like substances at the bottom of the one that is not working and the one next to it. The other 4 tubes do not have it. These two tubes are both the same date codes while the others are different. Could these tubes just be bad? The solder connections have been checked and re-soldered again. No progress.

The right tube in this image is the problem.

[Kevin A.]

I see. The soot is certainly not typical. The next step I would take would be to try and test one of the tubes. You should be able to do this in circuit if you are careful. 

The IN-8-2 pinout can be seen at the bottom of this page: http://www.tube-tester.com/sites/nixie/data/I/IN-8-2/in-8-2.htm

First, I would use a multimeter to check that there is good ( > 170 volts) high voltage present at the anode pin with respect to earth.

Then, turning the clock off, I would attach a wire to ground that has a resistor in series. For the IN-8 at 190-170 volts, I think 20-25K should be a good current limiting resistor value.

Then, you can manually attach it to one cathode at a time to see if the digit lights up, independent of the control circuitry. If the tube does not not light, then indeed the nixie tube itself is probably the issue.

If high voltage is present and the tube works fine during this experiment, then the problem will trace back to the control circuit, which we can diagnose if that is the case.

To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/4e3d6fd6-8bf1-4c54-9abc-4931dd352663n%40googlegroups.com.