Trouble shooting a midipal build


Built Midipal today (v0.3). First time SMD soldering. Seemed to go quite well though :slight_smile:

3.3v measured OK at marked points and AVR flashing all went fine. However getting a blank (but lit) display.

Flashed the LCD test referenced in another troubleshooting thread here. The LED’s flash fine but the LCD is still blank. BUT if powered via the ISP header the LCD does display ‘HELLO’ but not if powered via battery/DC connection. I’ve checked various points, including Vdd/Vss pin on the diplsya and I seem to have a fairly constant 3.3v when Battery/DC powered but the display is still blank.

Please help confused as what the check next.

Ok scratch that - Fixed now! It was the damn Trim Pot - obviously with a higher voltage it did not need much adjustment, with 3.3v however though it did. Took alot of turns however to get the display visible.