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 Trouble with double LEDs lighting in test mode
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By: Anonymous: dbetz@xlisper.com () on Friday, May 14 2010 @ 06:39 PM PDT (Read 2896 times)  
Anonymous: dbetz@xlisper.com

I finished assembling my Bulbdial Clock but unfortunately it doesn't seem to work correctly. I seem to be having trouble with the LED1:1 and LED 2:1 signals. I get the following sequence of LEDs lighting when I try to manually step around the blue ring:

D14/D24
D14/D24
D34
D54
D64
D15/D25
D15/D25
D35
D45
D65
D16/D26
D16/D26
D36
D46
D56
nothing (should be D21)
D31/D32
D41/D42
D51/D52
D61/D62
nothing (should be D12)
D31/D32
D41/D42
D51/D52
D61/D62
D13/D23
D13/D23
D43
D53
D63

It seems like I can explain all of the double LEDs with a problem with D1:1 and D2:1 but I've checked the solder connections to those MPU pins and the circuits connected to them and can't find a problem. Anyone have any suggestions?

Thanks,
David Betz





       
   
By: Windell (offline) on Saturday, May 15 2010 @ 12:57 AM PDT  
Windell

Was it doing this before you added the second and third rings? Or, did this only start with the additional rings?

Sounds like you might have a short circuit between the LED1 and LED2 signals-- that would explain why it goes dark on the D12/D21.


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By: Anonymous: David Betz () on Saturday, May 15 2010 @ 04:55 AM PDT  
Anonymous: David Betz

I guess I've solved my problem. I looked over the blue board and noticed that a number of the leads for the LEDs touched the PCB where they were bent at a right angle. I pushed them away from the PCB a little and now all of the tests run without error. It seems that the LED leads can short against the board even though there is a solder mask on the board. Now I just need to align all of the LEDs and assemble the case. Thanks for your help.





       
   
By: Windell (offline) on Saturday, May 15 2010 @ 11:41 AM PDT  
Windell

>It seems that the LED leads can short against the board even though there is a solder mask on the board.

Yes, that's true: Solder mask is not uniform enough to rely on it as an insulator. I'm glad that you got it working.


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