Avionics (Radio Problem) Narrowed Down... I Think???

Received a new relay on Wednesday, plugged it into the audio panel and
slid the audio panel back into the stack this morning.

Took off out of Georgetown, after making my radio calls (with sidetone
on every call), turned downwind, and set the trim for a 300 fpm climb,
while I started tuning in frequencies. First SAC ATIS.... Loud and
Clear. Second NorCal approach... Loud and Clear. Back to GT freq
123.05 and heard numerous calls at Marysville and Cameron Park.

As I continued to climb, through 7000 feet, I considered turning right
45 degrees and heading over Lake Tahoe as the winds were calm and the
weather was gorgeous. As I prepared to turn, I noticed Nevada Co.
airport and Grass Valley off to my immediate left. Tuned into the
local frequency, let them know my position and asked for a radio
check.... LOUD AND CLEAR!

Waved hello to Jim (probably didn't see me), and decided I would head
back home and get some chores done, even though I could have flown all
day! Did I mention it was gorgeous out there?

Thanks for everyone's patience and help over the last few months! I'm
so glad to think this nightmare could finally be behind me, and am
ready to head up and get that instrument currency, now that I can
communicate!!! I just hit 6 months without my approaches a few weeks
back, so I'll have to go up with a friend and get some hood work done.
After that, I'm looking for some of that Valley fog, as I'm ready for
some actual!!!

Best Regards,
Todd