Primary O2 sensor (a/f ratio) circuit failure

[marshaul]

I recently had what appeared to be 02 sensor failure, however after replacing the sensor the problem persisted. After testing multiple sensors and verifying the integrity of all the wiring, I'm forced to conclude the problem is in my K-Pro'd ECU.

I called Hondata and the option they offered was to obtain a replacement ECU then pay $150 to swap the K-Pro.

I'm an EE and I thought I would see if I can identify the problem and attempt a board-level repair before I drop this kind of cash. Has anybody on the forum attempted this before? Does anybody have any tips to offer before I get started?