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Ice Tube Clock - Only One Segment Lights Up
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Ice Tube Clock - Only One Segment Lights Up

by Kombi on Sun May 24, 2015 10:48 pm

First, let me openly admit to being a novice at both electronics and soldering. I bought this kit as a way to build both skills, but I've run into a problem I can't seem to resolve through the troubleshooting steps.

Everything had checked out with the build up to the point where I performed the first test of powering up the VFD tube. It is here where I was met with the disappointment of only a single segment of the tube lighting up and blinking.

Image

I've done a few checks of the board to make sure everything was copacetic. The only thing that I've wondered about was the diode at D3 being so close to the high voltage transistor that it seems impossible to solder these without creating a bridge. I have a hunch this is intentional, but it is the one area I can't be certain of.

At any rate, here's the pictures of the board and my soldering. I'm really hoping this is a boneheaded mistake on my part.

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If anything is unclear let me know and I can take additional pictures.

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Re: Ice Tube Clock - Only One Segment Lights Up

by adafruit_support_bill on Mon May 25, 2015 6:13 am

Nice clear pictures, thanks!
Your soldering looks good (yes, the bridge is intentional). There is some excess flux you might want to clean. It sometimes causes problems, but I don't think that is the case here.

Double check your tube alignment. Make sure that the 'NC' leads are aligned with the correct holes.

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Re: Ice Tube Clock - Only One Segment Lights Up

by jarchie on Mon May 25, 2015 8:22 am

Kombi wrote:Everything had checked out with the build up to the point where I performed the first test of powering up the VFD tube. It is here where I was met with the disappointment of only a single segment of the tube lighting up and blinking.

This is one of the ways in which a bad Q3 can present, so bypassing Q3 as a diagnostic might be worthwhile.

On recent boards Q3 is marked as Q4. The fact that your board is marked Q3 suggests that you have a ZVP3306A for Q3. Is that correct? This part has caused problems in the past, and more recent kits include a ZVP2110A which is a better fit for the circuit.

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Re: Ice Tube Clock - Only One Segment Lights Up

by Kombi on Mon May 25, 2015 12:13 pm

adafruit_support_bill wrote:Nice clear pictures, thanks!
Your soldering looks good (yes, the bridge is intentional). There is some excess flux you might want to clean. It sometimes causes problems, but I don't think that is the case here.

Double check your tube alignment. Make sure that the 'NC' leads are aligned with the correct holes.


I did do a double check and they do align well. Of course the fact that I now need glasses and magnifying lens to see this clearly is exposing some failures in my biological hardware.

jarchie wrote:This is one of the ways in which a bad Q3 can present, so bypassing Q3 as a diagnostic might be worthwhile.

On recent boards Q3 is marked as Q4. The fact that your board is marked Q3 suggests that you have a ZVP3306A for Q3. Is that correct? This part has caused problems in the past, and more recent kits include a ZVP2110A which is a better fit for the circuit.


My kit did come with the ZVP3306A for Q3 and I thought I was especially careful with it given the warnings they had in the instructions at this point. Nonetheless, this did the trick, upon placing the jumper the tube lit up and it started flashing with all the digits and it was clear that it was keeping time at that point.

I would guess that leaving the bypass probably isn't the best solution so is this something where I could just get a ZVP2110A and just swap it into place?

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Re: Ice Tube Clock - Only One Segment Lights Up

by adafruit_support_bill on Mon May 25, 2015 12:19 pm

Good to hear. Replacing a Q3 is a LOT easier than re-soldering a tube.
Please contact support@adafruit.com with a link to this thread and we can send a replacement Q3

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Re: Ice Tube Clock - Only One Segment Lights Up

by Kombi on Mon May 25, 2015 1:01 pm

adafruit_support_bill wrote:Good to hear. Replacing a Q3 is a LOT easier than re-soldering a tube.
Please contact support@adafruit.com with a link to this thread and we can send a replacement Q3


I'll say, I was really dreading the possibility that I'd have to do that again. I'll get the email sent and of course, thank you for your help.

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Re: Ice Tube Clock - Only One Segment Lights Up

by jarchie on Mon May 25, 2015 1:27 pm

Kombi wrote:My kit did come with the ZVP3306A for Q3 and I thought I was especially careful with it given the warnings they had in the instructions at this point. Nonetheless, this did the trick, upon placing the jumper the tube lit up and it started flashing with all the digits and it was clear that it was keeping time at that point.

This is probably not your fault. A while back, there was a period where quite a few people were reporting Q3-related issues. At the time, the most plausible explanation seemed to be static damage, so Adafruit support amended the build instructions to include an appropriate admonition. But ever since Adafruit changed their kit to use the ZVP2110A, the only Q3-related issues reported on this forum have been with older kits using the ZVP3306A. Both parts are FETs and should be similarly sensitive to static damage, but the new part seems reliable. So I believe that very few Q3-related issues are actually due to static damage.

If you're interested in the technical reasons that the ZVP3306A is more prone to failure in this circuit, check out this thread.


Kombi wrote:I would guess that leaving the bypass probably isn't the best solution so is this something where I could just get a ZVP2110A and just swap it into place?

While you wait for a replacement from Adafruit, leaving the bypass should be okay and will allow you to finish your clock. The only downside is that the battery backup will not work while the bypass is in place. Also, do not install the battery itself until after the bypass has been removed and Q3 upgraded; otherwise, you will probably end up with a dead battery.

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Re: Ice Tube Clock - Only One Segment Lights Up

by Kombi on Tue May 26, 2015 12:04 am

Well I got a quick reply from customer service saying the part would be shipped out so that's fantastic.

I definitely appreciated the help and quick spotting of the problem jarchie.

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Re: Ice Tube Clock - Only One Segment Lights Up

by Kombi on Sun May 31, 2015 2:39 pm

Success!

Image

Adafruit customer service shipped the new MOSFET (ZVP2110A) out to me in rapid fashion. So I just got it installed and tested and the clock now behaves as expected at this step.

Thanks a million for the help diagnosing and ultimately resolving the problem.

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Re: Ice Tube Clock - Only One Segment Lights Up

by adafruit_support_bill on Sun May 31, 2015 3:43 pm

Awesome! Glad you've got everything up and running.

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Please be positive and constructive with your questions and comments.