apologies if this is something very simple i have overlooked
but i am using the Morse Encoder library
http://raronoff.wordpress.com/2010/12/16/morse-endecoder/
and it was all working fine pulsing out messages received on serial usb on pin 13
however when i connect a wireless shield or my older xbee shield for that matter the chat between the two xbees works fine and the board receives the messages fine, encodes them and sends them back to the sender however the LED on 13 pulses so faintly you have to be looking straight down it to see that anything is happening, and the same for the small led straight on the arduino uno board,
the shield seems to be having some effect on it, i have run other bits of code to test toggling an led on and off to check its not a power draw thing or anything like that and 13 is capable of powering a led at full brightness so not sure what's going on...
any suggestions are much appreciated
many thanks
ben