OpenSprinkler Forums Hardware Questions DIY Kit Assembly Questions LCD is backlit but characters are rectangles Reply To: LCD is backlit but characters are rectangles



Howdy thisisit. I have been exceptionally busy over the last month, so I haven’t been able to troubleshoot my PCBs to my satisfaction. They have been sitting idle for a few weeks with no resolution.

I don’t know your technical expertise, but I can tell you what my approach will be when I resume troubleshooting these PCBs in a few weeks. My ethernet section (the ENC28J60, the RJ45 jack and all the discrete components) appears fully functional, as does the power supply section. I’m not concerned that the triacs don’t actuate at this point. I am concerned about the data lines on the µC that are driving the LCD, the 74HC595N and the relay (the sections that are non-functional). It would be very interesting to wire the µC (and associated circuitry) and the LCD separately on a breadboard and see if the LCD functions. It may be that there was something on the PCB that was dragging down a data line or two. That could also be simulated by carefully bending pins up on the µC and reinserting it into it’s socket. My USB section (or rather it’s communication with the µC) is also suspect. The CH340G ICs I bought from China came in a non-ESD bag from the vendor, so its possible that some have been damaged, including the one I installed.

I wanted to thank you for your inquiry, as it has renewed my interest in repairing my PCBs and rehashing my previous efforts has also given me a few more things to try, including isolating the µC from the:
• CH340G
• DS1307
• Relay circuit
• SD card socket
• Valve driver circuit

Good luck and please post your findings. It may just help someone else.