Tried it on an IC FM stereo detector, works
I used an AM/FM board from a junked gettho blaster and modified the stereo decoder (a chip) to detect TV sound stereo. Easy mod: add a cap to the RC circuit that has the trim pot to tune it to the 15.7KHz pilot. The detected sound has excessive high audio frequencies, which is likely due to differing preemphasis with TV sound vs FM radio. Also, if the bandwidth of the TV IF circuits is too narrow, there will be some "scratchy" distortion products in the L-R signal. Also the signal will need to be stronger.
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