Quote:
Originally Posted by Steve McVoy
The tuner conversion consisted of realigning the coils and putting new decals on, if I remember correctly.
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If my set is a correct example, which it may not be as it was shipped around to various RCA places as a test bed ....
It most certainly was NOT "realigning" the coils! The alignment range on my oscillator coils if FAR too small. In fact, except for (current) channels 3 and 4 its insufficient to get the sound carrier to tune properly into range of the fine tuning, which even on 3 and 4 barely has enough range.
The coils were actually rewound. This is obvious looking at them.
The tuner design is very, very bad indeed. The main problem is that the tuning wafers on the switch are too large in diameter, meaning that wires are too long. The coils are too big. Some are not even coils ... they are straps that are very low inductance. In fact I had to augment the width of one
by soldering on a strip of copper sheet about 3/16 x 3/4 inches to get
one coil to tune correctly (to the "intermediate" channel set to which my set is tuned.). I do note that I have tried heterodyning
"cable series" channels down into range of channels 1, 2, and 5 (oscillator frequency under the incoming frequency) and they
work fine by fine tuning the frequency synthesizer.
Also the 6J5 was likely the best tube to use, in its time, but still, the distance from the socket tabs to the tube elements is rather too long.