0

3 Defective LEDs On My MiniPOV
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

3 Defective LEDs On My MiniPOV

by KQRR4449 on Tue Jan 17, 2017 8:30 pm

I sent an Email concerning this problem yesterday and was informed I should also provide proof that the board was assembled correctly. Hopefully, my 2nd try will work.

I ordered the MiniPOV kit on 12/21/2016, invoice #1313815. Assembly was easy and it worked fine for a few days. The colors of 3 of the LEDs then looked wrong. I downloaded 3 picture files in sequence. 1 was pure red, one was pure green, and the last was pure blue. I found that 3 green LEDs were not working. The red and blue LEDs worked fine on all 8 LEDs.

I next attached my oscilloscope to LED-C-GREEN and the LED-A-x signal for the good and bad LEDs. The scope showed that the LED-A-x dropped to the green LED Voltage when activated on the good LEDs. The bad LEDs showed no Voltage drop which showed that the green LEDs were open. I have attached a .zip file with photos of the boards and the scope traces."LED 1 Green Bad 400ns.bmp" is a scope trace of 1 of the 3 bad green LEDs. "LED 2 Green Good 400ns.bmp" is a scope trace of 1 of the 5 good green LEDs.

I believe I have sufficient experience to correctly assemble this board. I have an MSEE degree from Stanford University and 35 years of experience in digital hardware and software. I have included several photos in the .zip file. "MiniPOV Top.jpg" is a photo of the top of the MiniPOV board. "MiniPOV Bottom.jpg" is a photo of the bottom of the MiniPOV board. Unfortunately, many of the bottom solder joints are obscured due to the double sided foam tape. The MiniPOV board was assembled using full ESD protection and a temperature controlled digital soldering station set to the recommended 650 degrees F.

To assure you that my assembly skills are adequate, I have included 2 photos of a test DCC Booster I designed and built for the National Model Railroad Association (NMRA) for use in DCC conformance testing. "Booster Top.jpg" shows the top of the Booster board. "Booster Bottom.jpg" shows bottom of the Booster board.

I have also included a photo of my workbench. As you can see, I have an ESD mat and wrist clip on the work surface and a digital temperature controlled soldering station.

Could you send me 3 replacement LEDs so I can fix the MiniPOV? I have provided my adress below.

Thanks very much for your help.

Kenneth West
7328 SW 184 Place
Aloha, Oregon 97007
503-501-7473 (Cell)
Attachments
MiniPOV Bad LEDs.zip
(274.68 KiB) Downloaded 49 times

KQRR4449
 
Posts: 8
Joined: Tue Jan 17, 2017 7:45 pm

Re: 3 Defective LEDs On My MiniPOV

by adafruit_support_carter on Wed Jan 18, 2017 12:02 pm

Assembly job looks excellent! Thanks for providing the info.

Send an email to support@adafruit.com along with a link to this thread and we'll send you a replacement kit.

adafruit_support_carter
 
Posts: 10966
Joined: Tue Nov 29, 2016 2:45 pm

Re: 3 Defective LEDs On My MiniPOV

by KQRR4449 on Wed Jan 18, 2017 8:10 pm

Thanks very much for your help. I have sent an Email to support@adafruit.com.

KQRR4449
 
Posts: 8
Joined: Tue Jan 17, 2017 7:45 pm

Re: 3 Defective LEDs On My MiniPOV

by KQRR4449 on Wed Jan 18, 2017 10:32 pm

I found a labeling error in the MiniPOV4 schematic while I was debugging the LED problem. The wire label LED-C-BLUE and LED-C-RED are interchanged. This does not affect the layout but makes it tricky to trace the wiring from the schematic.

I have attached an updated zip file containing the corrected Eagle files. I also scooted some of the parts labels over a bit to make things easier to read. Feel free to update your Eagle files if you would like.

Thanks again for all your help and for producing a fun POV device to play with.

Sincerely,

Kenneth West
kgw4449@gmail.com
Attachments
Adafruit MiniPOV4 Kit Edited.zip
(93.73 KiB) Downloaded 42 times

KQRR4449
 
Posts: 8
Joined: Tue Jan 17, 2017 7:45 pm

Please be positive and constructive with your questions and comments.