OK! Solved my own problem :)
Here's how I did it in case anyone else has to do this:
The backpanel of the TV includes a 3.5mm audio jack (center-top here). I happened to have a 3.5mm to RCA adapter (like this) -- I connected the 3.5mm male input into the TV and the RCA male outputs to the...
I'm at my family's home for the holidays and trying to do a little tech support...
Their TV is a Sharp Aquos TMAN-A043WJZZ (see manual here). They use a Roku stick (via HDMI) to watch everything (no cable box) -- this all works fine using the TV's own speakers.
Now, they also have an old Bose...