Ice Tube Clock Runs Slow

[wg6h]

Hello,
Recently I built one of the Ice Tube Clock kits.
The clock looks great and is working OK except it does not meet specification as far as time keeping accuracy.
The documentation says that it should be +/- less than two seconds per day. My clock loses more than five seconds per day compared to NIST radio station WWV.
I checked the value of the two 20 pfd NPO capacitors and they are very close to the correct value within 5% or better. In the parts list it shows these as being 22 pfd. Could that be the problem?
Do you have any suggestions to improve the accuracy?
Thanks,
Bill

[BruceF]

I'd suspect the crystal as being the source of your problem rather than the caps, but I'm no expert. If you're willing to do a little tweaking, you could try one of the firmware releases that include drift correction, or you could try a ChronoDot or GPS hardware mod. I'd try a software mod if I were in your situation, but my Ice Tube is accurate enough that it isn't worth messing with. I did do a brightness mod on it though, which is so awesome I think it should be rolled into the core kit.

[adafruit_support_bill]

Most are accurate to within a few seconds/day. But the drift can be affected by several things - including ambient temperature.
You could try a different crystal, or the software drift-correction as suggested by BruceF.