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Ice Tube Partially Lighting up
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Ice Tube Partially Lighting up

by beatter on Sun Jun 01, 2014 12:57 am

I just put together my ice tube clock and sadly the digits are only partially lighting up. When first turned on it starts out with a few full digits lit up, then gets worse over time until it's basically just a couple of lines.
I've gone through the troubleshooting steps, checked the voltages and double checked the soldering (it's not the best, but I don't think it's the problem).

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Re: Ice Tube Partially Lighting up

by jarchie on Sun Jun 01, 2014 1:51 am

Sounds like an issue with Q3. Try removing the clock battery and soldering a temporary jumper between the two outer pins of Q3.***. Be careful not to touch the center pin of Q3 with the jumper; accidentally doing so risks blowing the microcontroller. If you can manage to jumper the outer pins of Q3 with alligator clips or other connectors, that's fine as well.

Q3 acts as a power switch for the VFD filament and driver chip. Adding a jumper bypasses Q3 and ensures the filament and driver chip are always fully powered. Assuming Q3 is the problem, your clock should work fine when powered with the AC adapter. But since the filament and driver chip can no longer be turned off, the backup battery will not be able to supply enough power for the clock to keep time during sleep. And if you accidentally leave the backup battery installed with Q3 jumpered, the battery will be drained extremely quickly when the clock tries to sleep, so if you don't remove the battery, it will likely wind up completely dead.

*** Edit/clarification: The two "outer pins of Q3" are the pins closest and farthest from the edge of the board. (They are "outer" pins with respect to Q3--not with respect to the board.) So for the jumper test, connect the pins as shown below:

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Re: Ice Tube Partially Lighting up

by adafruit_support_bill on Sun Jun 01, 2014 6:28 am

Good advice from jarchie. If the clock lights up with a jumper between the two outer pins of Q3, that confirms a Q3 problem & we can discuss the options from there.

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Re: Ice Tube Partially Lighting up

by beatter on Sun Jun 01, 2014 10:51 am

Thanks for the replies!

Looks like that did the trick, after placing the jumper, everything lit up just fine!

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Re: Ice Tube Partially Lighting up

by adafruit_support_bill on Sun Jun 01, 2014 11:06 am

OK. So your Q3 is not working well. If you contact support@adafruit.com with a link to this thread, we can send a replacement.

Q3 is a MOSFET and very sensitive to damage from static while handling. Jarchie and some others have come up with some alternative options you may wish to consider as well: viewtopic.php?f=41&t=51283&p=263684

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Re: Ice Tube Partially Lighting up

by jarchie on Sun Jun 01, 2014 2:46 pm

Replacing Q3 with another ZVP3306A usually solves the problem just fine, but my personal suggestion is to replace Q3 with a ZVP2110A, available from Digi-Key (ZVP2110A-ND) or Mouser (522-ZVP2110A). Another excellent 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. 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.

By the way, if you're interested in what I believe to be the underlying reason for the problem you describe, it might be worth checking out this post.

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Re: Ice Tube Partially Lighting up

by kai_h on Sun Jun 15, 2014 7:17 am

I'd just like to chime in to say that I also had some segments not lighting up, and it was indeed the Q3 transistor. I've bypassed it with a jumper wire for the time being and have emailed support to see what I can do. Seems to be a relatively common problem - whilst I'm used to handling computer components and not zapping them, this little blighter seems to be REALLY sensitive.
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Re: Ice Tube Partially Lighting up

by adafruit_support_bill on Sun Jun 15, 2014 8:58 am

@kai_h - Yes. The bypass test pretty much confirms it. If you reference this thread when you email supprot@adafruit.com we can send a replacement Q3.

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Re: Ice Tube Partially Lighting up

by kai_h on Sun Jun 15, 2014 7:38 pm

Thanks Bill - I've emailed support with a link to this thread.

One thing that may be worth looking at is if that MOSFET can be shipped with it's pins stuck into the black anti-static foam that the ATmega and a few other devices are stuck in. It wasn't until I got to the step where I was installing it that it said that the device was highly sensitive to static - if it were stuck in the foam, then I would have noted that fact when I was counting all the pieces to make sure they were there (which is most likely when it would have been zapped as I didn't take any particular precautions with handling it at that stage)
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Re: Ice Tube Partially Lighting up

by Rafa_BR on Tue Jul 01, 2014 8:04 pm

Hi...

I have the same issue with Q3... When I add a jumper between the outer pins, I can see display power on.

Thanks.

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Re: Ice Tube Partially Lighting up

by adafruit_support_bill on Wed Jul 02, 2014 9:10 am

@Rafa_BR - Please post some clear photos of the front and back of your main board.

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Re: Ice Tube Partially Lighting up

by Rafa_BR on Wed Jul 02, 2014 5:25 pm

adafruit_support_bill wrote:@Rafa_BR - Please post some clear photos of the front and back of your main board.


Hi Bill...

Since yesterday, when I made the jumper and it worked, I already removed the Q3. Anything else I can do?

Thank you.
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Re: Ice Tube Partially Lighting up

by jarchie on Fri Jul 04, 2014 5:22 pm

I would suggest upgrading Q3 to a ZVP2110A; see my post earlier in this thread.

Adafruit support may have overlooked your post before, but I suspect they will offer to replace Q3.

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Re: Ice Tube Partially Lighting up

by Rafa_BR on Fri Jul 04, 2014 6:38 pm

@adafruit_support_bill?

Thanks a lot for the tip, Jarchie, I will consider the ZVP2110A as you mentioned.

It´s not easy to me get a ZVP3306A or ZVP2110A in my city. :(

Best.

Rafa

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Re: Ice Tube Partially Lighting up

by jarchie on Fri Jul 04, 2014 6:43 pm

What about the PN2907A/resistor combination? Those parts are more commonly available.

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