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I read the troubleshooting FAQ, didn't help.

I do not have any audible sound from the speaker, no clicking, no LED flashing. All my solder joints look good.

I have 3 V on the battery terminals, I have some voltage across my Geiger tube (I don't yet have a 1Gb resistor).

I get no clicks or LED flashes when I short the 2 ends of the Geiger tube.

I need some more troubleshooting tips. What voltage should I measure at various points in the circuit? Can I measure voltage from TP2 to various resistors to see what is wrong? How about the IC pinouts, what should the voltages be on the pins?

Well, first of all, did you turn on the power switch?

There's a list of voltages for the 555 and HV pins here: http://www.mightyohm.com/forum/viewtopi ... t=10#p5489

Double check all component placements and values. If you attach a photo showing both sides of the board I can help you spot components installed backwards, wrong value, etc. It doesn't hurt to add a tiny bit more solder to any connections that look suspect in any way.

I did find a bad solder connection. Now when I short the 2 ends of the tube the speaker beeps and the LED lights up, I've tried this multiple times, it always works. I measure 176V from TP2 to ground (I don't yet have a 1GOhm resistor). All the 555 voltages match those on the above page.

But there are still no background counts, no beeps or LED flashes regardless of the potentiometer position.

The speaker beeps and LED lights up when I short the tube so does that imply that the geiger tube is bad? I measure about 1 MegaOhm across the tube.

Is there any other way to test the tube to see if it's bad ?

Do you know what the input impedance of your multimeter is?
That voltage reading sounds about right - it's likely that you are using a 10 MegaOhm input DMM but it would good to check.

1 Meg across the tube is low - it seems like your tube is leaky. How does the high voltage change when the tube is installed vs. removed?

Any updates? Did you get your kit working?

I had a similar problem.

And strangely all my Ground Pins are reading 2.6v - not sure how that happened.

Anyway - reflowing and checking all the joints did the trick.

Works like a charm

The two solder joints that seem to cause the most problems are the battery terminals. If the negative terminal isn't soldered really well, it can cause all sorts of strange things to happen - including a voltage greater than 0V on 'ground'.