Hello everyone! I've just built my first ergodox. Unfortunately, when I plug in the left hand side, I am left with a constant and unstoppable repetition of asdfg<tab>asdfg<tab>asdfg<tab>asdfg<tab>asdfg<tab>....etc. etc. or whichever keys are configured on that row (ie: I've tried several different hex layouts; from the online ergodox configurator). This continues until the keyboard is unplugged, not just the problematic left hand side. I assume the teensy is buffering these keystrokes or something. Having just the right hand side plugged in works great, but plugging in the left hand side results in a usb reload and either instant spamming, or full/semi keyboard unresponsiveness. I've been able to use the left hand side just once (excluding the home row), but with poor performance (pressing one key quickly after another didn't register, like the teensy/something was overloaded). Most of the time when plugging in the left hand side, it just spams asdfgasdfgasdfg forever.
I believe I have narrowed it down to the IO expander on the left hand side, but I would like the communities input on this as I am not what you would call an expert.
Here are some awful cell phone pictures which feature wholly inadequate lighting. Please excuse the fluxsplosion and accompanying flux scuff marks caused by multimeter probing:
IO-Expander:
http://i.imgur.com/1wYhvXE.jpgBoard-general:
http://i.imgur.com/9g08G6G.jpgThe problem row in question matches up to the pin circled in red, which i'm calling pin5. When the keyboard is plugged in, measuring voltage from ground on the IO expander (circled in black, top left) to each of the yellow pins (representing other rows) results in ~4.92v. Measuring from ground to pin5, circled in red, results in 0v.
Measuring continuity between pin5 on the IO expander and the key switch pins circled in blue in the second picture results in a beep, showing a completed circuit from the keys to pin5. This is the behaviour when measuring from pin4 to the row above, pin3 to the row above that etc. etc.
Measuring continuity of each switch measuring between switch pins and pressing the switch down also results in a successful circuit, suggesting switches are all good.
Diode testing using the diode multimeter function results in a measurement of ~0.600 for each diode on the entire board. This measurement is taken from the adjacent through-hole copper rather than placing the leads on the surface mount diode itself, so I know that the diodes are in contact with their pads.
Anyways, I've reflowed the problem pin a couple times (though now I know it has connection because of the continuity testing between it and the keys), I've removed the capacitor and bridge there, I have tested and quadruple checked that there are no shorts elsewhere on the board, I have looked through clickclack123's similar problem here
https://geekhack.org/index.php?topic=54288.0 and looked elsewhere, and I am officially out of ideas aside from starting to replace parts.
I'd appreciate any suggestions!
Thanks