Any suggestions what to try next?
Do you have a voltmeter? If so, measure your input voltage by putting your red (+) probe on the + PCB pad and your black (-) probe on the - PCB pad. What do you read for that voltage? Then do the same with 5V and 3.3V and let us know what you see for each of the two voltage rails. They should be within 5 percent or so of their expected values.Cris, That didn't work. I have not been able to communicate with the device to update the firmware.
I have a problem similar to this one. Was there a bad batch of processors sent out during the summer? Mine shipped early July but just got around to soldering it. The LCD comes on, I get a long beep, but the screen is blank. Pin 1 is 0V, is that supposed to be 3.3V? Resistors all seem to be in just fine, capacitors are the correct polarity and the 3.3 and 5V regulators seem to be working.I thought I should give a final update on my Eggfinder LCD build. I was unable to get the unit to wake up after assembly so I shipped it to Connor McGrath to see if he could figure out what was wrong. He said he could not get it working either. All the solder joints looked OK but the main processor was not working. Connor shipped it back to the factory and sure enough the processor was bad. Eggtimer replaced the kit and I had Conner assemble the new kit. Today I was able to finish the assembly and try the receiver out with the TX unit I had built previously. Hurray! Everything is working perfectly. I had five satellites and "found" the TX unit in the back yard. I can't wait to try it out in a rocket!
I'd like to give a big shout-out to Connor for all his help diagnosing the issue. Also to Eggtimer for replacing the unit no questions asked.
Yeah it's just like the OP's picture submitted. If I turn the contrast all the way up I get one blank line and one solid line. Adjusted down and the screen is blank. Would a picture be of use? I guess flashing would be the next step?Not aware of any bad processors... the one that was in the OP's kit may have not been flashed properly. If you get a beep, the processor is working... did you adjust the contrast?
I measured about 0.2V on that pad, must be a short somewhere. I'll snoop around, thanks for the tip.If you're referring to Pin 1 of the processor, that's the RESET pin. If it's at 0V, then it's being pulled low by a solder bridge or reset button, if installed. Check your solder joints around the 10k resistor that's adjacent pins 3 and 4, making sure the leads aren't shorting to the PCB GND plane; and check the RST pads on the corner edge of the PCB.
OK. If you're getting a solid line and a blank line on the LCD, that suggests that the processor is not communicating with the LCD module. There are two possible (at least) reasons for this:No no, i'm saying I had the + and - leads on my volt meter reversed.
I'll do some more checking tomorrow, but as far as I can tell everything is okay. Are there maybe some specific pins that are more likely than others? I do believe the processor is booting up, because it there will be some blocks, then they will go away then they come back. I think this is the processor attempting to show some different text.OK. If you're getting a solid line and a blank line on the LCD, that suggests that the processor is not communicating with the LCD module. There are two possible (at least) reasons for this:
1. Your processor is not booting up, or is dead. Since you do hear a long beep when you power it up, then this is probably not the case. It is booting up and initialising.
2. Your LCD module is faulty, or the connection to the LCD is faulty. This is more likely the case.
As Cris suggested, check the header connections to the LCD.
If I back off contrast I see nothing. But this is a 2 line lcd screen right? Why would I only get one line showing with contrast all the way up. Strange. I'm going to attempt a reflash. If that works maybe i can just try another display.What happens if you back off the LCD contrast? Do you see any characters, instead of blocks?