The board (Mega168 based) seems superficially to be working. The power light is on fine and an LED on p13 is slowly pulsating (I'm guessing this is a program pre-loaded by the chap who made it).
Yes, the pin 13 LED should be slowly pulsing on and off, this is normal and expected.
Any idea what diagnosis steps I could take now to find the fault?
- When you first click program, does the pin 13 LED begin rapidly blinking for a short period then resume pulsing? This indicates the board is correctly receiving the reset signal.
- Use a wire to jumper pins 0 and 1 (RX/TX), then use a terminal program to connect to the port. Are your characters echoed back?
- Is it a straight-through serial cable? generally these are male-female.
- Are you powering the board with an external power supply rated between about 7.5V and 20V?
- There are directions for setting the IDE with upload.verbose. Using these will let you see the actual call to avrdude. Copy the command, paste it into a terminal and provide the results, this gives a much better understanding of where it's failing.
Could the serial port be misconfiguration (I notice that there are a fair few "settings" for an ttySx interface) - if so what might the required settings be?
The serial port should be configured to assert it's DTR line on open, or at very worst, assert the DTR line on close. This is typical, but who knows. The Arduino IDE should be capable of configuring anything else.
Did you purchase a pre-assembled board or the kit? The pre-assembled version gets the pulsing program installed after it's assembled, so we know it worked before. The kit version just has it burned to the chip, and we have a whole slew of potential assembly issues. Feel free to fire off an email to firstname.lastname@example.org
for support as well.