Top Half of LEDs not turning on for RGB Matrix Shield, 16x32

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cupofjava
 
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Top Half of LEDs not turning on for RGB Matrix Shield, 16x32

Post by cupofjava »

I recently purchased a 16x32 LED matrix, an RGB Matrix Shield for the Arduino, and a 4A power supply from Adafruit. I soldered the shield together and plugged in the matrix to the power and shield, and I used the "scrolltext_16x32" example code. The top half of the leds do not turn on, and the bottom half is limited, and only shows blue. I believed at first it was a problem with the for the 16-pin ribbon cables, but even after resoldering the components, the matrix does not show the full spectrum of colors.

I do not know if it is a problem with the shield itself, the ribbon cable, the soldering job, or even the matrix itself.

I've attached pictures displaying the matrix on, the shield, the soldering job, and the back of the matrix for reference.
matrix issues.jpg
matrix issues.jpg (420.61 KiB) Viewed 308 times

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johnpark
 
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Re: Top Half of LEDs not turning on for RGB Matrix Shield, 1

Post by johnpark »

Please upload a clear, high-resolution picture of the connections, wiring, and soldering and we can try to see if those are the culprits.

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cupofjava
 
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Re: Top Half of LEDs not turning on for RGB Matrix Shield, 1

Post by cupofjava »

I've attached a picture showing the wiring and soldering on the shield; the Arduino is connected to the computer as power, and the matrix is connected through a DC power connector to the 4A switching power supply sold on this website.

When the ribbon cable is tilted at certain angles, I've noticed that the matrix sometimes would light the red LEDS on the top half in which they would somewhat light along with the scrolling text program but only in red (the row of lit LEDs slowly moved upwards as the text scrolled to the left, and although many of the lines showed the remaining section of the letter in some, it lit the entire row of LEDs)*see attached picture, text is supposed to be "MEH".

Also, I have seen the matrix flicker all its LEDs white before, so I do not think the matrix's LEDs are the problem. I believe that the issue may be within either the ribbon cable itself or the shield (itself or its soldering).
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wiring and soldering.JPG
wiring and soldering.JPG (973.72 KiB) Viewed 280 times

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johnpark
 
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Re: Top Half of LEDs not turning on for RGB Matrix Shield, 1

Post by johnpark »

It's a bit hard to tell, but seems there's a chance there are little solder spray overlaps between some pins on your connector header on the shield. Could you give those a good scrub with a brush and confirm none of them are shorted to each other?

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cupofjava
 
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Re: Top Half of LEDs not turning on for RGB Matrix Shield, 1

Post by cupofjava »

I've cleaned the solder connections as much as possible, but the matrix unfortunately still does not work correctly.
solder after cleaning.JPG
solder after cleaning.JPG (195.57 KiB) Viewed 257 times
However, at one point when I was testing, the matrix had suddenly used all colors and worked nearly perfectly. Both halves were on, and the colors showed in the scrolltext demo as intended. When I unplugged the ribbon cable and put it back in, it stopped working once again and returned to like before.

Some details that may help:

- When I touch the ribbon cable, colors will flicker on the matrix, including the half that does not turn on regularly.
ribbon cable.JPG
ribbon cable.JPG (290.16 KiB) Viewed 257 times
- When the matrix is unplugged from its 4A power supply with the rest of the wires kept plugged (input, arduino to usb), the half that turns on shows only red. When it is plugged back in, red does not show up.

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