For the op notes: 

An rapidly alternating RED/GREEN LED flash indicates low DC input voltage. (less than approximately 9.5V). A steady GREEN on the LED indicates RX mode.

The PIC senses this using R3/R4 divider.

On 08/22/2020 3:40 PM Zack Widup <w9sz.zack@...> wrote:

I think there is a problem with my unit. I have not done any modifications to it yet. When it starts out, the LED turns on green, then pulses red for just a moment, then goes into an alternating red and green pattern forever. It is not sending CW. It is just an alternating green/red.  What does this signify?

73, Zack W9SZ

On Sun, Aug 9, 2020 at 9:02 PM John N9ZL < jbrooks@...> wrote:

Doug,

If you've corrected the LED orientation (they were installed backwards by accident when manufactured - so reverse the colors if you're looking at a virgin board), then the LED is as follows:
Red on initial power up for a second or two, then it blinks, then stays green.
Green on receive, red on TX.
If you activate the key or the ptt leads, then the led goes red.
If you activate both the key and ptt, then the unit sends CW and blinks the LED with the CW.
In beacon mode, if you're on CH A, it sends CW, if you're on CH B, it sends audio tones over FM.  The LED is the same for both.
CH A/B doesn't make a difference for how the LED works.
If you're on FM PTT, then one unit must be on CH A, and the other on CH B.  
If you're on CW using the key, then both units must be on the same CH - either A or B.

Again, if you're using the board as it came from China/Australia, the LED colors are reversed from what I have listed here.  I took my LED out and flipped it the right way when I installed it in the case.

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