We had some customers reporting problems with the LCD 20x4 Bricklet. In some cases, especially in conjunction with the usage of a Dual Relay Bricklet, there seemed to be a problem with non responsive displays or slowly dimming backlights. After some investigation we found a possible reason for this. The I2C Port Extension MCP23017 is used on this bricklet. Unfortunately there is a bug in the reset circuitry of this chip on all of our LCD Bricklets. In some cases it can happen, that the reset circuitry of the IC is triggered. Fortunately we found a workaround for this problem and have shipped LCD 20x4 Bricklets with it since early August. Since the feedback for the LCD Bricklets with the workaround was all around positive, we have to conclude that this was really the reason for the problems. You can recognize a fixed LCD Bricklet by a small capacitor that is soldered between two pins on the big IC in the middle of the LCD 20x4 Bricklet:
If you have the described problems with your LCD20x4 (not responsive or slowly dimming backlight): Please contact us at info@tinkerforge.com, we will replace your old LCD 20x4 Bricklet with one that has the workaround.