Got some problems that are way over my head

[andrewrx]

Here goes: I have a fully assembled all-in-one PCB v. 3.1, but something's off that I can't diagnose or fix.

I'll start by describing what I know is working. All the components are in the right place, the right way (double checked) . I'm getting power, all over the board. Also, the first thing I did when I had problems was recheck joints: all seems well. Plus, when I plugged it in the the computer recognized it, plug n' play seems to be swell. Even the LCD backlight comes on But, and here we get to the issue, there's no text on the LCD. I tried to adjust the contrast using the buttons, no dice. I checked the voltage between pins 1 and 3 on the LCD and it was way too high, but Isn't it supposed to be adjusted by the Atmega?. I connected pins 1 and 3 on the LCD. Which effectively set the contrast to 100%, but I only got one line of boxes. Which, I believe, is also supposed to point me in the direction of the Atmega. Thought I might as well try to update the firmware, never could get the proceed button to come up. It may not need to be said but It's not getting any trigger info, although it was recognized as a midi-via-usb device by my DAW. If anyone could point me in the right direction, I would be extremely grateful.

Thank you.

[Firelord]

The LCD problems and possible fixes are described here. If you think that you have that sorted out, then there is some problem on the board or the ATMega isn't programmed correctly or is at fault.

[Synthex]

Make sure the flat cable is well pressed into the LCD connectors.

[andrewrx]

I tested continuity from the LCD to the board. The LCD flat cable is connected correctly. I went through the suggestions on the LCD problems post and tested the LCD. I believe the LCD is fine and have gotten to part 3 in Dmitri's post.

Let's assume you sorted out the contrast and the LCD is not faulty but you're still not able to see VU meters (without any input activity VU meters look like just like underscore symbols in all character positions of the LCD) or the MegaDrum menu. This means one of or a combination of some of the following:

1. Atmega is faulty. Replace Atmega.
2. Atmega is not programmed. Program Atmega.
3. A faulty Atmega crystal. Replace the crystal.
4. Incorrect capacitors connected to the crystal. Replace capacitors.
5. Atmega is working properly, e.g. tested with MIDI activity, but data communication with LCD is broken. Check connectivity between pins 4-14 of the LCD and the board right to the pins of Atmega and that there are no breaks/short circuits on those data lines. If you're sure that the connections are ok, than your LCD is faulty.

I believe that the capacitors are right (#4). MCT never sees reponse from the board, so I assume that the Atmega isn't proven to be working (#5). I also believe the PIC is working because it is recognized as a USB device. Is there anyway to figure out which of these other problems might be at fault (problems #1-3)? Or something else entirely? What would you suggest is the next step?

[Firelord]

What would you suggest is the next step?

Well, if neither MIDI triggering nor LCD work, then the problem could be in ATMega itself. I would check the board near ATMega for shorts/breaks first. Then I would carefully remove ATMega from its socket, wipe the pins with some isopropyl alcohol and put it back. Then I'd check the board for remains of flux and wash it off also with isopropyl alcohol. Afterwards I'd take an ISP programmer and reflash ATMega.