I assembled my Monochron kit about a week ago. Discovered that the RTC didn't work, as per this thread. I replaced the DS1307 with a Chronodot and that solved the ticking problem, all was well. Then after running fine for about 36 hours, the display went wonky. The top half of the display was blank, and everything was displaying only on the lower half. It looked like an old TV that had lost vsync.
In case it was a software problem, I reflashed the firmware. I tried multichron and ratt, but the problem persisted.
I figured there might be a bad solder joint or two, and while trying to find the problem I learned all about water soluble flux and had a nasty education, as per this thread. I removed my modifications to the board, removed the ICs and battery, and gave the board a thorough clean.
The problem remained. Wondering if the problem was with the screen itself, I hooked that up to an arduino and tried the example sketch in the ks0108 library, and found the display is working perfectly.
Back to the monochron pcb. I figured that maybe the cleaning I had done, did not remove all the traces of water-soluble gunk. It was possibly still hiding underneath the 20-pin connector for the LCD, or maybe hiding under the dip28 connector. I removed them both, thoroughly cleaned the board of water-soluble residue, and replaced both connectors. The problem remained.
Finally, wondering if the Atmega328p was itself the culprit, I replaced it with the one from my arduino. I used a usbtiny to flash it with the bootloader and the fuses, then used the ftdi friend to flash the ratt firmware. And the problem with the display remains. The top half is blank, the bottom half has both upper and lower images appearing.
To ensure I'm not going nuts, I took the Atmega328p out of the monochron, put it back in the arduino, burned the arduino bootloader back onto it, wrote the ks0108 sketch back to it, and verified that the display itself is still fully functional.
So at this point I have:
- Cleaned the board
Tried different firmwares
Verified the display itself is functioning
Replaced the dip28 and 1x20 sockets
Replaced the atmega328p
What is left for me to try / test / replace? At this point the only thing left is the PCB. Is it multi-layer? Could there be damaged traces inside that I can't see? The traces I can see are not damaged.
The fact that it's only the top-half of the screen should be a clue - I'd have thought maybe it's the chip-selects that is buggered, except they control left-side / right-side, don't they? If one of the /CS lines were stuck or shorted, wouldn't that cause the screen to be messed up horizontally?
The monochron is such an attractive clock, I don't want to give up and scrap it. But I don't really want to have to replace the whole thing. Could I order a partial kit, i.e. everything except the display and case?
Any help would be most appreciated!
Thank you & cheers!
p.s. I can provide photos of the display problem, pcb, whatever else might help figuring this out. I've been at it all day and it's left me stumped, frustrated, and tired.
