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Ice Tube Clock digits not staying lit up properly
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

Ice Tube Clock digits not staying lit up properly

by theomegatiger on Thu Feb 27, 2014 6:19 pm

I finished putting my cube together about an hour ago and have been troubleshooting it for a while. What's happening is that when I plug in the clock everything lights up properly at first, blinking time every second. After a moment or two some of the digits starts to flicker and stop lighting up, this can be temporarily "rectified" by power cycling the clock. Sometimes if I'm lucky the parts of the digits will light up again, other times it just gets worse till nothing shows up on the display. I've double, triple and quadruple checked my solder joints and checked for bridges. I even touched up some solder joints on the display board and the pins to make sure everything was good. I'm really not sure what is going on with this thing. This thread here viewtopic.php?f=41&t=50347 seems a bit like the issue I'm currently having.

Below are a couple videos I took to try and show the problem.

http://youtu.be/kMeaIGBqCCk

http://youtu.be/gfrsewtvSx0
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Re: Ice Tube Clock digits not staying lit up properly

by adafruit_support_bill on Thu Feb 27, 2014 6:33 pm

If you post photos of the front and back of the main board we'll look it over. This problem is sometimes caused by a reversed or a bad Q3.

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Re: Ice Tube Clock digits not staying lit up properly

by theomegatiger on Thu Feb 27, 2014 7:06 pm

adafruit_support_bill wrote:If you post photos of the front and back of the main board we'll look it over. This problem is sometimes caused by a reversed or a bad Q3.


I double checked with the build instructions and the Q3 seems to be properly oriented with the flat spot and rounded edges matching up with the silkscreen.

https://www.dropbox.com/s/x5p385avcrlv8 ... 173957.jpg
https://www.dropbox.com/s/4406pywh483n0 ... 174018.jpg
https://www.dropbox.com/s/0wlgtvad8hvdj ... 174035.jpg
https://www.dropbox.com/s/zfji1vwyhfd5w ... 174049.jpg
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Re: Ice Tube Clock digits not staying lit up properly

by adafruit_support_bill on Thu Feb 27, 2014 8:19 pm

Q3 looks like it is oriented properly. Let's try replacing it. If you contact support@adafruit.com with a link to this thread, we can arrange that for you.

Like any MOSFET, Q3 is very static sensitive. Use care in handling it - especially in the winter season when static can be a real problem. It is best to work on an anti-static surface. And to ground yourself to that surface before picking up the device.

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Re: Ice Tube Clock digits not staying lit up properly

by daveh225 on Sat Mar 29, 2014 4:21 pm

This perfectly describes the issue I'm having. Did replacing Q3 fix the problem?

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Re: Ice Tube Clock digits not staying lit up properly

by theomegatiger on Sat Mar 29, 2014 5:35 pm

I haven't installed the new Q3 as for some reason my display is working correctly 99% of the time, I did however get a replacement Q3 from Adafruit so that in the event that it does fail completely I can easily replace it.

DaveH225 wrote:This perfectly describes the issue I'm having. Did replacing Q3 fix the problem?
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Re: Ice Tube Clock digits not staying lit up properly

by jarchie on Sun Mar 30, 2014 2:20 am

DaveH225 wrote:This perfectly describes the issue I'm having. Did replacing Q3 fix the problem?

This problem has been happening quite often over the past few months and has always been successfully solved by replacing Q3. In a few cases, Adafruit has replaced Q3 with another ZVP3306A. In a few cases, users have replaced Q3 with a ZVP2110A. In a couple cases, users have replaced Q3 with a PN2907A/resistor. All three replacements have worked. The most informative thread describing your symptoms is probably this one.

My recommendation is to upgrade Q3 to a ZVP2110A, available from Digi-Key (ZVP2110A-ND) or Mouser (522-ZVP2110A). An equally good alternative is the is the PN2907A/resistor combination described by Russell27.

Replacing Q3 with a ZVP2110A or PN2907A/resistor will provide more voltage to the VFD filament and prevent two other problems that occasionally effect Ice Tube Clocks: First, the dim digit problem is where the initial and/or final digit appears significantly dimmer than the others and is caused by the low filament voltage in the Adafruit design. Second, low filament voltage also accelerates cathode poisoning, which can shorten tube life and make the 3rd and 6th digits appear dimmer than the others. A clock with both issues is pictured in the initial post of this thread.

Hope that helps.
--John <www.jarchie.com/email>

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Re: Ice Tube Clock digits not staying lit up properly

by daveh225 on Fri Apr 04, 2014 10:57 pm

Thanks for the info John. I actually went and bought a replacement ZVP3306 from Mouser and have just replaced Q3. That certainly did the trick. Unfortunately I did it before reading your post. Why is the ZVP2110A considered an upgrade? I'll be placing another Mouser order soon and wonder if I should add one to my order. One other thing that I have noticed is that I have 28V on D3, as opposed to the 14-16V as mentioned in the troubleshooting thread. What issues do you think this might cause, and is it related to the issue as described in this thread and Q3?

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Re: Ice Tube Clock digits not staying lit up properly

by jarchie on Sat Apr 05, 2014 12:39 am

DaveH225 wrote:Why is the ZVP2110A considered an upgrade?

I promise that I'm not trying to be difficult, but I thought I answered this question in my last post:

jarchie wrote:Replacing Q3 with a ZVP2110A or PN2907A/resistor will provide more voltage to the VFD filament and prevent two other problems that occasionally effect Ice Tube Clocks: First, the dim digit problem is where the initial and/or final digit appears significantly dimmer than the others and is caused by the low filament voltage in the Adafruit design. Second, low filament voltage also accelerates cathode poisoning, which can shorten tube life and make the 3rd and 6th digits appear dimmer than the others. A clock with both issues is pictured in the initial post of this thread.

But if the explanation above is unclear, maybe you can suggest what can be explained better?
--John <www.jarchie.com/email>

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Re: Ice Tube Clock digits not staying lit up properly

by jarchie on Sun Apr 06, 2014 4:31 pm

My apologies, Dave. I completely ignored the second part of you question:

DaveH225 wrote:One other thing that I have noticed is that I have 28V on D3, as opposed to the 14-16V as mentioned in the troubleshooting thread. What issues do you think this might cause, and is it related to the issue as described in this thread and Q3?

I do not believe this is related to Q3. I'm assuming that you're measuring the boost voltage at D3, and a voltage level of 28v is fine. The Adafruit design adjusts the tube brightness by adjusting the boost voltage, and the IV-18 tube is designed to handle up to 60v. When you adjust the tube brightness through the menus, does the brightness of the tube change as expected? If so, the boost circuit is working properly.

By the way, please do let me know if I should elaborate as to why I consider the ZVP2110A to be a better choice than the ZVP3306A in the kit. If you're interested, Russell27 posted a more systematic comparison of transistors in the context of Q3. Later in that thread, I posted some measurements showing power noise from the ZVP3306A that, when extreme, seem to cause the flaky segment problem you experienced.

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Please be positive and constructive with your questions and comments.