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Ice Tube Clock display flickering
Moderators: adafruit_support_bill, adafruit

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Ice Tube Clock display flickering

by chanakaya on Tue Oct 28, 2014 3:22 am

flicker1.gif
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Hi,

I have had the Ice tube clock working fine for the past few months. Since the past month, the display has started flickering, becomes progressively worse and eventually turns off. If I turn off the power and then turn it back on, the display comes back on fine for sometime and then the flickering starts again. Any ideas on what could be wrong and suggestions to fix it will be greatly appreciated.

--chanakaya

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Re: Ice Tube Clock display flickering

by MikeHg on Tue Oct 28, 2014 3:37 am

May be a defect Q3? You could try to shortcut Q3 and see what happens.

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Re: Ice Tube Clock display flickering

by adafruit_support_bill on Tue Oct 28, 2014 5:48 am

That could be a Q3 issue. Q3 controls the heater bias current to the tube to reduce power demands when running from the backup battery. If you short the two outer pins of Q3 together, it will bypass Q3. If shorting Q3 results in a steady display, we can look into the options for fixing it.

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Re: Ice Tube Clock display flickering

by chanakaya on Tue Oct 28, 2014 7:28 pm

Thanks Mike and Bill,

It looks like that was it. With Q3 shorted, the flickering is gone. Please let me know on next steps.

--chanakaya

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Re: Ice Tube Clock display flickering

by adafruit_support_bill on Tue Oct 28, 2014 8:08 pm

If you contact support@adafruit.com with a link to this thread we can send a replacement Q3.

Several form members have developed alternative solutions with commonly available parts. If you are interested, this thread has more info on that: viewtopic.php?f=41&t=51283&hilit=q3+mosfet

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Re: Ice Tube Clock display flickering

by MikeHg on Wed Oct 29, 2014 4:06 am

May be you want to choose the PN2907A / 1k resistor combo. I used the equivalent 2N2907A, which has a metal cap (see picture).

This combination works quite well and is not as sensitive as the MOSFET.

Regards,
Mike
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Re: Ice Tube Clock display flickering

by chanakaya on Thu Nov 06, 2014 4:05 am

Thanks Mike. I am going with the replacement from Adafruit. If that fails, I will try your suggestion.
regards,
chanakaya

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Posts: 3
Joined: Fri Jul 20, 2012 2:09 am

Please be positive and constructive with your questions and comments.