Grounding issue with two-legged bi-color led

[Michael2]

Hi all,

I just cannot get a red/blue led to work in my latest project. It is a two-legged version and I used AMZ's schematic: http://www.muzique.com/news/bicolor-led-in-stompboxes/ where I changed the resistors to 1K for blue and 330R for red. Power is 9 volts.

It is working but ONLY if I take off one earth connection at a time. If both earth connections are hooked up, only one of the colors is working (the one that is green in AMZ's schematic). 

I have tried all day to make it work but cannot find the culprit. What am I doing wrong? Is it impossible with this led?

Here are the specs of the led:
1. Type: Light Emitting Diode
2. Size(mm): 5mm
3. Lens Color: Milk-White(Diffused)
4. Emitted Colour: Red/Blue
5. Polarity: Polar Changing
6. Forward Voltage (V):
RVF: 1.9-2.1V
BVF: 3.0-3.2V

I hope someone can help me out here...

[thermionix]

The AMZ schematic you linked has two 10k resistors forming a voltage divider to get 4.5v.  The other side of the dual LED is switched between 0v and 9v, to determine which way the current will flow and which color LED will light.

I'm not understanding what you are doing with 1k and 330r.

[Michael2]

Oops, than I totally misunderstood the whole idea about AMZ's layout. I will try it exactly as it says. Thanks.

[Michael2]

That worked. Thanks for your help Thermionix.

[thermionix]

No problem at all, glad I could help.