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Channel 12, in that era, was originally WDEL-TV with most programming originating from Wilmington. It transferred to new ownership as WVUE - The Broader View. It later went dark and returned to the air as an educational station with the transmitter relocated to the Phila tower farm in Roxborough.
Philco engineers believed fine tuning was unnecessary because its early TVs had an AFC circuit using voltage derived from the audio detector. The tuner oscillator should be set using a DC voltmeter in the AFC test jack. Set for 0 volts or just a touch negative since they tend to drift positive.
The fine tuner will not affect the sound detector voltage polarity on later TVs using intercarrier sound, so Philco reverted to traditional fine tuning.
That's a great example of an early TV.
Don
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