I finally came around to unpack and test a pair of basic moteinos R4 (RFM69HW) I bought back in 2015. Programming and Radio communication work like a charm, but the LED is hardly visible. So I did some measurements and discovered, that the digital outputs of the Atmel only provide little more than 50 µm (indeed = 0,05 mA). The regulator works fine and nothing changes when I bypass it by feeding 3.3 V into the appropriate pin. It also does not matter whether I power it from the Breadboard or with the FTDI adapter.
All of the above was tested with two moteinos. I have a third still wrapped, which I will carefully unpack and try tomorrow.
What is wrong there? The LED shines so nicely during the programming, but as soon as I address it directly it's just a glimmer :-[
Perhaps the LED pin (D9) is being used for something else and it is being reset very shortly after you set it. Another alternative is that you're using analogWrite vs digitalWrite to turn it on. analogWrite(LED_PIN, HIGH) would be very dim indeed. Finally, and I'm sure this could NOT be the case ;), you haven't set the pinMode to OUTPUT...
Tom
Noooo! That was indeed my mistake, not defining the output. :'(
Shame on me! Thank you so much!