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bi-color led help

Started by Jesse, November 02, 2017, 03:19:39 AM

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Jesse

I know it's not a Madbean pcb, but I hope I could get some help with it.  It's a GPCB Mini-me.  Im new at this.  Everything works except the status led.  I tested the pcb before I boxed it but mounted the led later.  I followed the wiring diagram exactly except i did not use the battery snap or dc jack for the battery.  The pedal works and sounds good, but I would like to have the led work.  It's a common anode bi-color led.  If I put power to it with a 1k8 clr from a 9v battery and some jumpers it lights up red or green depending on which cathode I connect to...so I know the led is good.  Am I missing something here?

Leevibe

#1
I would suspect the solder joint on the cathode. That looks like it could be a cold joint. Maybe reflow it and test. 3PDT switches can be finicky too if the iron is on them too long.

mjg

If you've got a multimeter, you can check the wires and 3PDT switch.  Check the continuity (or resistance) between s5 on the board and s4 or s6.  It looks like it should have s4 and s5 connected with the switch in one position, and s5 and s6 in the other position. 

If that all checks out (or not), you can narrow down the trouble shooting. 

Jesse

So... I ohmed s4, s5 and s6 from the 3pdt to the pcb and have continuity thru all three wires.  I also have continuity from s4 to s5 in one switch position and continuity from s5 to s6 in the other switch position.  I reflowed all three solder joints at the led connection to the pcb.  I also ohmed from all three led legs to the solder joints at the pcb and got continuity thru all three legs.  I can still power up the led (both red and green)  from a 9v battery with a clr and some jumpers by connecting negative from the battery to the anode (middle pad on D3) and positive from the battery to the 1k8clr to cathode "red" or cathode "green"... Still stumped.

mjg

Umm, I often get confused with anode/cathode, so take this with a grain of salt...but it sounds like your LED is common cathode, not common anode.  So the LEDs would effectively be backwards, so they won't light up. 

Jesse

I think the problem is I have a common cathode bi-color led and what I need is a common anode bi-color led!  Well I went a different route and removed the led, s4 s5 and s6 from the pcb and went with a wire from 9v to a 1k8clr to the middle of the 3pdt then one wire to one anode and one to the other anode then from the cathode of the led to ground on the dc jack and it works!!  Thanks for all the help guys...

Jesse

Mjg...you were totally right!

mjg

Good to hear you got it working.   :D