didja ever stop to think that maybe nobody has any idea what to tell you?
Hey, you're the one with the BSEE, not us. Not everything is simple to diagnose and troubleshoot over the internet.
That's why good, experienced technicians with the right test equipment make good money. Sometimes troubleshooting takes quite a bit of time. It may only be a $.25 part but it may take several hours to find out which one. The tech deserves to be paid for his time, doncha think?
One would have thought at this point in your career you might have realized that. But then again, some engineers do tend to see themselves as the stars of the field and discount the skills, experience and talents of the "underlings".
Now, try to impress your plumber by telling him you're a BSEE whern your pipes are blocked. Betcha he doubles his estimate...