No sound from 40PFL7705DV's coax digital output to soundbar
I have a 40PFL7705DV TV with software version PHL-0DA_713_0. The TV's coax digital output is connected to a Haier soundbar's (model SBEV40-SLIM) optical digital input via a coax to optical converter. However, I do not get sound from either over the air TV or roku (connected to the TV via HDMI) through the soundbar when its S/PDIF mode is selected.
I verified the problem is not with the soundbar, cords, or converter since I get sound when it is connected to a different television set's coax digital output. As such, I think it must be an issue with a setting on my Philips TV.
I appreciate any insight or advice on how to fix this issue. Thanks!