Ice Tube Clock (Tube has no display)

[adafruit_support_bill]

So everything looks good, except your bias voltage drops when you connect the tube.

What are the voltages on pin 5 and pin 13 of the Atmega chip?

[fmaznicki]

Pin 5 has 1.5mv and pin 13 has 1.21v i'm not sure if i'm counting the pins in the correct order however i used this diagram as a reference for similar numbering/layout

[jarchie]

Does the fuse get hot after the clock is on for 10 seconds or so?

Is D2 in the correct orientation?

[fmaznicki]

The fuse did get hot when I was flipping the board over while powered on to test the voltages. But when laying flat with no movement it doesn't get hot. D2 is in the correct orientation as you can see from this picture.

http://i.imgur.com/2jjT0E9.jpg

[fmaznicki]

Here is a couple more pictures of it all cleaned up.

http://i.imgur.com/tOVQEsu.jpg
http://i.imgur.com/b3W8dxn.jpg
http://i.imgur.com/OUeySlP.jpg

[jarchie]

D2 is in the correct orientation as you can see from this picture.

Thank you for humoring me. Beautiful pictures, by the way. Sorry I couldn't help, but Adafruit support is awesome and they'll figure it out.

I have one last suggestion, but it's risky and only worth trying if Adafruit support recommends it. That being said, I just did it (without hesitation) on my clock, and my clock still works great.

Power the clock, press the MENU button, find a short segment of wire, and (with a steady hand) temporarily short pin 1 and pin 3 on Q3. (The pins closest to the edge of the board and the pin furthest from the edge of the board. Be careful not to touch the center pin.) When you press the MENU button you should hear a "tick" from the piezo. While shorting Q3, the tube should light. After the test, touch the fuse to make sure it isn't hot. If the tube lights and the fuse isn't hot, I would suspect that Q3 is bad and unable to sufficiently amplify the signal from the microcontroller. If the fuse is hot, I'd suspect a high resistance short somewhere along the route from Q3 to R3 to VBIAS. If the tube doesn't light, look at the filaments carefully to see if they dimly glow red.

[adafruit_support_bill]

Thanks for the input jarchie. You know these clocks pretty well.

Shorting Q3 is a worthwhile test to run. Based on the voltage measurements, it looks like your battery sense circuit is seeing power and pulling the gate of Q3 low. The question is why the VBias voltage drops as much as it does.

Proceed carefully, as there is high voltage in the vicinity. You might want to tack-solder one end of the jumper to pin-1 of Q3 so you don't need 3 hands to complete the test.

[fmaznicki]

Thanks for your suggestions.

No love, not even a dim red glow when shorting Q3. Tube is definitely getting power but not lighting up, as seen with my multimeter. I used a small paperclip bent in a u-shape to short out so I wouldn't have to tack solder it.

it's tough to troubleshoot stuff without known-good components so i've placed an order for a new tube and mini-pcb with header, if this doesn't work at least we'll be able to narrow it down a bit.

I'll let you know when it arrives and i test it out.

[jarchie]

No love, not even a dim red glow when shorting Q3.

That's disappointing. I really thought that would work.

I used a small paperclip bent in a u-shape to short out so I wouldn't have to tack solder it.

I realize Adafruit support's method is safer, but I prefer the U-shape wire method also.

i've placed an order for a new tube and mini-pcb with header, if this doesn't work at least we'll be able to narrow it down a bit.

That's exactly what I would have tried next if it were my clock. If the problem does turn out to be the tube, check to see if Adafruit support will send you another tube & side PCB. It's always good to have a spare.

Good luck!

[adafruit_support_bill]

If the problem does turn out to be the tube, check to see if Adafruit support will send you another

Absolutely. If it is the tube we can replace the bad one or refund you for the extra one you purchased.

[fmaznicki]

New tube just arrived today. Popped it in and fired up without a glitch! Even though I went through a bit of frustration with it not working all in all it was a great troubleshooting experience and I learned a lot! Clock looks great, thanks again Adafruit!

[jarchie]

Beautiful pic... Bravo!