Quad Alphanumeric Display issue

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jj3
 
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Quad Alphanumeric Display issue

Post by jj3 »

I've assembled the quad alphanumeric display with i2c backpack, and am getting an issue with the lower right corner (both the bar and decimal point) not lighting up. I've checked solder joints, connections, chips and resistors and all seem to be good. I'm leaning to a bad decoder chip right now.

It's running off a 5v trinket, with the Vcc and Vi2c connected to the 5v output from the trinket

Any thoughts of what to check, or will I need an RMA for a bad chip?
Test with a zero
Test with a zero
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Test with an asterisk
Test with an asterisk
FullSizeRender.jpg (73.56 KiB) Viewed 460 times

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Franklin97355
 
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Re: Quad Alphanumeric Display issue

Post by Franklin97355 »

Could you post clear pictures of both sides of your board showing any soldering you have done and the connections to it?

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jj3
 
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Re: Quad Alphanumeric Display issue

Post by jj3 »

It's non-leaded solder, so a bit peaker than I'd like, but it's what I had on hand. Attached is both sides of the board:
FullSizeRender.jpg
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adafruit_support_mike
 
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Re: Quad Alphanumeric Display issue

Post by adafruit_support_mike »

It looks like you might have a couple of solder joints along the bottom of the photo that haven't wetted the pad completely.

Just to be sure, give any joint that isn't a nice cone a dab of flux and reheat it until it flows freely. If that doesn't help, we'll call it a bad chip.

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jj3
 
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Re: Quad Alphanumeric Display issue

Post by jj3 »

I fluxed and ran through all the solder joints on the board, same issue.

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Franklin97355
 
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Re: Quad Alphanumeric Display issue

Post by Franklin97355 »

Please email [email protected] with a link to this thread for a replacement

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danlee58
 
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Re: Quad Alphanumeric Display issue

Post by danlee58 »

I have 2 of these Quad Alphanumeric Displays. I am Writing to them over the I2C bus. I only have one unit on the bus, but have tried both with the same results. I get an Acknowledge when I Write to the unit from my Coridium SuperPro board, but I can't get any Segments to light on either board. The code was written in 'C'.

Can you post a copy of your I2C Address/Command/Data that you used to display the Zeros?

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jj3
 
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Re: Quad Alphanumeric Display issue

Post by jj3 »

I slightly modified the example "quadalphanum_mini" in the examples from the Adafruit LED Backpack library.

The basic code would be:

Code: Select all

#include "Adafruit_LEDBackpack.h"
#include "Adafruit_GFX.h"

char *message = "****    0000    ";

Adafruit_AlphaNum4 alpha4 = Adafruit_AlphaNum4();

void setup() {
  alpha4.begin(0x70);  // pass in the address
  alpha4.clear();
  alpha4.writeDisplay();

  // send a message!
  for (uint8_t i=0; i<strlen(message)-4; i++) {
    alpha4.writeDigitAscii(0, message[i]);
    alpha4.writeDigitAscii(1, message[i+1]);
    alpha4.writeDigitAscii(2, message[i+2]);
    alpha4.writeDigitAscii(3, message[i+3]);
    alpha4.writeDisplay();
    
    delay(800);  //So you have time to verify all the little bits are glowing properly
  }

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jj3
 
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Re: Quad Alphanumeric Display issue

Post by jj3 »

Missed the ending }... apologies!

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