I’ve completed the build of the TB2 and everything seems ok, except that the lcd screen is lit, brightly, but shows no characters and the contrast pot doesn’t seem to affect anything. I can hear sounds when I hit the keys, the led glows…all seems ok but the the screen. How do I go about troubleshooting it? Any suggestions where to start?
Worth noting, I’ve double and triple checked all the solder connections, diode and caps. I’ve hit the reset button a half-dozen times and I’ve recompiled and uploaded the firmware. Again, everything seems ok except the screen.
I’ve tried quite a few turns in both directions with no change in the lcd. Is it possible to turn it too much? The trimmer seems to be the correct component. As the backlight is on, it seems I have voltage. I was going to see if I could test data next.
Nope, you can’t turn it too much – the mechanism just skips over the end point on either side.
You may also need to check the soldering on the Arduino Due’s header. It’s a little harder to check since the solder connections are under the pcb out the lcd. But you can check them with a multimeter if you remove the Arduino Due. To see which pins are connected, have a look at the Fritzing schematic.
I tested the pin outs with my voltmeter and there was definitely a problem with a few of the connections. Perhaps I damaged the circuit board…I’m not sure. I has a bit of thin copper wire around and I was able to run jumpers between the bad connections, reset the circuit board and, viola!, I have a functioning TB2. Thanks for the support. My only issue during the troubleshooting was following the lines on the Fritzing diagram, I didn’t know how to isolate connections or do anything with the program. I was also too lazy to learn 😀