Quote:
Originally Posted by Electronic M
The original Zenith cobramatic changers did NOT have turnover cartridges. The first year models 1948 were 78 RPM only, and later models that had 33RPM had a single stylus that was a compromise tip size part way between LP and 78. The Zenith designed cobra pickup was originally a variable capacitance cartridge that FM modulated an oscillator tube that was demodulator for audio. None of these cartridges supported multiple styli. Zenith kept this scheme until the mid to late 50s then they switched to generic third-party ceramic turnover cartridges, but perplexingly kept using the cobramatic name and tone arm design for a while after the switch.
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OK, my bad, I was thinking that because I have an old Zenith S-9011 Record Player from the early 1950s that has a two tip needle arrangement that you have to "flip" the needle (its actually more of a cantilever) by pressing the back of the tone arm which allows the needle to switch between an LP or 78 Needle, and that record player is called a "Cobra-Matic".
Anyways that doesn't answer my question as to why the original factory phono input hookup on the back of this radio is not responding to any "electrical signals" being injected into the audio cable but will respond to "electrical signals" being injected directly into the phono input itself minus the audio cables.