Green LED

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Hi - Building Loopa and it’s going pretty well.
Although - for whatever reason, the green segment of the little RGB led (for SW13) that came in the essential kits (thank you for the spares!) is not lighting up in test mode. Red and Blue work fine for all, and green works for all but SW13. I can tell it’s out by the lack of the green flash in test mode and also when you move an encoder all the lights go white for a few seconds, but SW13 is purple. I replaced that led with one of the spares, and traced each lead to a resistor–>TBD62783 so the led is soldered correctly I assume, but green isn’t working.

EDIT: Tried Diode test mode on my meter but I can’t seem to get it to work with these little rgb leds.

Thank you

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Further searching I thought I found what these are…https://www.globalsources.com/LED-component/RGB-SMD-LED-1193867568p.htm. I’m just guessing but they look similar. That would place green diagonally opposite the CC symbol/diagonal cut. Although the PCB silkscreen says CC (common cathode?) but the diode illustration on that page looks to be common anode, so I probably have the wrong one.

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The LEDs are indeed common cathode type, not the same as the LED that you found. You should be able to light them up with a multimeter with the black lead on the the CC pin. Failing that you could use a current-limited power supply or a coin cell battery.

SW13’s green LED goes to R51 (220R; do you have the correct resistance?), then IC4 pin 11 and IC7 pin 3. Hopefully reflowing the pads will get it working.

Best,
Andy

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latigid on
Thank you I will try that. By the way, excellent work with these PCBs they are incredibly sturdy and the interconnect system between boards is really cool!

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Quck follow-up that was indeed it on IC3. Reflowed and it works. Thanks again

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Good to hear!