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sean4star wrote:Excellent! Everything is replaced and all is working again. Thanks for the help.

Good to hear. I had the same problem with mine. However mine seemed to be a problem with this one particular tube. I have not gotten up the courage to try it again on the board dont want to have to replace another component. But I probably will try it again once I get the rest of the board done. Ive finally gotten two rows done of coils. Now time to start soldering more components on the board to start the next two rows. Fun little project taking far longer than I had anticipated I do a few coils a night then my fingers grow tired of winding so I move on to gluing more coil formers together and then solder some more components.

I am finding some of the coil formers to be out of round so have started redrilling a new center hole after I glue the center circle in place at about the middle of the outter circle has anybody else had this problem?

Sometimes a miscut batch can slip through, I bin quite a few. How many are there and which part?.

As a start I tried to measure voltages at the 2 coils that had been working. It is about 11.97V at the ends of each coil. The measurement was made by placing the RED probe on the Red power terminal and then the black probe was placed on the brass screws that hold the coils to the PC board. [ I have the black PCB ].

Hope this is correct.

What should I do next to troubleshoot?

Are the ends of diodes and resistors tested in the same manner?

Here are some of the measurements on the Black Board:

1] Coils show 12V at all screw terminals

2] 2R2 Resistors: Left side of board shows about 12V on the lead away from the center and the lead towards center is 0V; The lead towards the center shows 0V and the lead away from the center is 12V [ Red lead of multimeter was on Red power terminal and probing was done with black lead of multimeter]

3] 6R8 Resistors: all show approx 12V at all ends [Probing done as for 2R2 resistors].

4] 5V Diodes: The voltage across the top vertical diode is 12V; The voltage across the other 2 diodes is less than 1V

5] 14V Diodes: Both show approx 15V across the diodes [red probe on black stripe end and black probe on opp side]

I hope this makes sense to you.

I must learn to be more careful as a lot of work has gone down the drain BUT I am learning as I go along.

Thanks in advance Tony.

I wish more folks would be active on this forum.

Hi,
Usually it's good news when it's quiet as you only hear about problems. It would be nice to see some completed boards though.

You need to take voltage measurments with the black probe on ground/oV and use the red probe to test. From the reading you've taken though it looks like the 2r2 is open circuit. Make sure there are no loose bits of wire that could have caused a short and replace it to see what happens.

I replaced BOTH 2R2 resistors. The Nixies do not work.

The voltage at the coil ends and all 2R2 and 6R8 resistors is 11-12V. What is the next step to troubleshoot the problem.

phil

Some more measurements - this time of the Diodes; the diodes were checked by placing RED probe on side of diode marked by black stripe and the other end was probed with the black test lead. Voltages were as follows:

1] 14V Zener diode shows 12V

2] 5V Zener that is ABOVE the PIC shows 2.38V

3] 5V Zener that is on the Left side BELOW the PIC shows 4.92V

4] 5V Zener on the Right side BELOW the PIC shows 0V

Hope this helps. I will await further instructions from you

phil

Check resistance to ground across the diode with 0V. It may be shorted or one of the mosfets connected to that clock line may be faulty. If it's being pulled to ground the other transistors won't switch on.

Check the voltage to ground at the 2 1R resistors/links in the centre of the board.

How many complete circuits do you have built up?. A photo showing the area you're working on would be a help.

Tony,

unfortunately I have already removed the bad resistors and what I thought was a bad diode. I will reinstall new pieces tomorrow morning.

What should the voltages be across these 5V diodes?

I fear the transistors may be bad too. Is there a way to test them?