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timesquare watch - 2 rows not working
Moderators: adafruit_support_bill, adafruit

timesquare watch - 2 rows not working

by siegeengine on Sat Dec 29, 2012 6:45 pm

My son recently finished soldering his timesquare watch together. I wasn't observing him the whole time, but he has made other soldering kits successfully before.

The watch appears to be working, telling time, etc, but the very top row of pixels doesn't work, and third from the top row doesn't work, but sometimes comes on for a bit. I inspected the solder joints visible from the bottom, and they seem ok.

Any hints on what to look for to help solve this problem?

Thanks
Eric
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Re: timesquare watch - 2 rows not working

by adafruit_support_bill on Sun Dec 30, 2012 6:26 am

It does sound like a soldering issue. You can check here for tips on how to repair common soldering problems. http://learn.adafruit.com/adafruit-guid ... n-problems

If you post clear photos of the soldering, we'll take a look too.
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Re: timesquare watch - 2 rows not working

by siegeengine on Sun Dec 30, 2012 12:34 pm

Thanks for the soldering page. I think the biggest problem I can see is solder coming from the back-side through the component side on some resistors. Attached are two pictures of the joints.

My worry is that I'll have to desolder the whole LED panel to get to the other side to fix any issues, unless there is some clever way to fix it from the visible side.

I'm also not expert enough to know which pins I should be inspecting which would be associated with the top, and 3rd from top rows.

Thanks
Attachments
TS_2.jpg
Time Square side 2
TS_2.jpg (542.79 KiB) Viewed 813 times
TS_1.jpg
Time Square side 1
TS_1.jpg (514.6 KiB) Viewed 813 times
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Re: timesquare watch - 2 rows not working

by adafruit_support_bill on Sun Dec 30, 2012 1:02 pm

Solder coming through to the front of the board is not a big problem unless it forms a solder bridge and shorts something out. I don't see evidence of that in the photos posted. The soldering on the display pins looks OK for the most part. The problem may be with the soldering on the microcontroller pins.

Page 3 of the spec sheet shows the relationship between pins and rows/columns. http://www.adafruit.com/datasheets/BL-M12A881.PDF
And the schematic shows the microcontroller pins that drive them. : http://learn.adafruit.com/assets/2872
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Re: timesquare watch - 2 rows not working

by siegeengine on Sun Dec 30, 2012 10:15 pm

Thanks. Those sheets don't show which physical pins map to which named pins, but I was able to build that map myself. I found 2 bum solder joints on 2 of the resistors. I added a little solder from the wrong side, and that fixed the problem. I'm glad I didn't have to desolder the LED panel.

Thanks!
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